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UNIVERSITY  OF  ILLINOIS 

AT  URBANA-CHAMPAIGN 

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y^o.8l-90 


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510.81; 
U63c 
no. 90 


EnKin. 


FERENCE  ROOM 


ENGWSERING  UBRARy 
mmRsljy  OF  ILLINOIS 


ed  Computa 


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BIBLIOGRAPHIC  DATA 
SHEET 


1.  Report  No. 

UIUC-CAC-DN-T3-90 


3.  Recipient's  Accession  No. 


4.  Title  and  Subtitle 

COMPUTATIONAL  MATHEMATICS  ABSTRACTS 


7.  Author(s)  Edited  Dy:   (ieneva  Bej.rora,  jonatnan  Lermit, 
George  Purdy,  and  Ahmed  Sameh 


5.  Report  Date 

October  1973 


8.   Performing  Organization  Rept. 

No.        CAC-90 


9.   Performing  Organization  Name  and  Address 

Center  for  Advanced  Computation 
University  of  Illinois  at  Urbana-Champaign 
Urbana,  111.   618OI 


10.   Project/Task/Work  Unit  No. 


11.  Contract/Grant  No. 

DAHCOU-72-C-OOOI 


12.   Sponsoring  Organization  Name  and  Address 

U.S.  Army  Research  Office 

Duke  Station 

Durham,  North  Carolina 


13.  Type  of  Report  &  Period 
Covered 

Re search- interim 


14. 


15.  Supplementary  Notes 


16.  Abstracts 


None 


17.   Key  Words  and  Document  Analysis.     17a.   Descriptors 

Numerical  Analysis 
Graph  Theory 
Mathematical  Programming 


17b.   Identifiers/Open-Ended  Terms 


17c.  COSATI  Field/Group 


18.  Availability  Statement  ^^    restriction    On    distribution 

ft-vailable  from  the  National  Technical  Information 
Service. 


FORM    NTIS-3S    (REV.    3-72) 


19.  Security  Class  (This 
Report) 

VNCLASSIFIED 

20.  Security  Class  (This 
Page 

UNCLASSIFIED 


21.   No.  of  Paees 


^ 


22.   Price 


USCOMM-DC    14952-P72 


CAC   DocTjment   No.    90 


Computat lonal 
Matheinatics  Abstracts 


Edited  by 

Geneva  Belford 
Jonathan  Lermit 
George  Purdy 
Ahmed  Sameh 


Applied  Mathematics   Group 
Center  for  Advanced  Computation 
University  of  Illinois   at  Urban a- Champaign 
Urbana,    Illinois   618OI 


October  1973 


This  work  was  supported  in  part  by  the  Advanced  Research  Projects 
Agency  of  the  Department  of  Defense  and  was  monitored  by  the  U.S. 
Array  Research  Office-Durham  under  Contract   No.    DAHC0U-T2-C-0001. 


!^iii^^^^ 


TABLE  OF  CONTENTS 

Page 

ERROR  ANALYSIS 1 

FUNCTION  EVALUATION  AND  COMPLEXITY  THEORY  k 

APPROXIMATION 6 

LINEAR  ALGEBRA. 10 

NONLINEAR  EQUATIONS , 15 

QUADRATURE - l6 

ORDINARY  DIFFERENTIAL  EQUATIONS  l8 

PARTIAL  DIFFERENTIAL  EQUATIONS 21 

FUNCTIONAL  EQUATIONS 22 

OPTIMIZATION 22 

ROOT  FINDING , 25 

GRAPH  ALGORITHMS. 26 

MISCELLANEOUS 27 

KEY  TO  REPORT  SOURCES 29 


ERROR  MALYSIS 


An  Error  Analysis  of  a  Method  for  Solving  Matrix  Equations 
by  C.  C.  Paige 

Let  B  =  [L  0]Q  be  a  decomposition  of  the  m  by  n  matrix  B 
of  rank  m  such  that  L  is  lower  triangular  and  Q  is  orthonormal.   It 
is  possible  to  solve  Bx,  =  b  using  L  but  not  Q  in  the  following  manner: 
solve  Ly  =  b  ,  solve  L'^w  =  y  ,  and  form  x  =  B  w.   It  is  shown  that  the 
numerical  stability  of  this  method  is  comparable  to  that  of  the  method 
which  uses   Q.   This  is  important  for  some  methods  used  in  mathematical 
programming  where  B  is  very  large  and  sparse  and  Q  is  discarded  to  save 
storage. 

STAN-CS-T2-29T      June  1972 


Rundungsfehleranalyse   einiger  Verfahren  zur  Summation   endlicher  Summen 
by  Arnold  Neumaier 

Der  bei   einer  Summation  auftretende  Rundungsfehler  kann  als  Mag 
fur  die  Gute  des  verwendeten  Verfahrens   gelten.      Im  folgenden  werden  fllr 
mehrere  Suiranierungs verfahren,    unter  anderem  fur  das   "ubliche"  und  das 
Kahan-Babuska-Verfahren,    a-priori-Schranken  fur  diese  Rundungsfehler 
S'^gegeben  und  miteinander  verglichen. 

PRAK  73/1  1973  28  pages 


Fehlerabschatzung  bei  nichtlinearen  Gleichungssystemen 
by    Rudolf  Krawczyk 

Fiir  eine  Losimg  x*   eines  nichtlinearen  Gleichungssystems    f(x)   =  0 
wird  eine  Fehlerabschatzung  bezuglich   einer  Halbordn\mg  angegeben. 
Gleichzeitig  kann  auch   eine  Aussage  uber  die   Eindeutigkeit   der  Losung 
gemacht  werden.      Die  Ergebnisse  werden  auf  Differenzengleichxmgen  und  auf  ein 
algebraisches   Eigenwert problem  angewandt . 

PRAK  73/3  1973  ik  pages 


Komplexe  Kreisarithmetik 
by    Norbert   Krier 

In   dieser  Arbeit  werden  Kreise  der  Gau3schen   Zahlenebene  als   kom- 
plexe Fehlerschrankenzahlen  betrachtet.      Da  aus   arithmetischen  Verkniipfungen 
solcher  Kreise  Mengen  hervorgehen,    die  im  allgemeinen  keine  Kreise  sind, 
werden  diese  Verkniipfungsmengen  diirch   Kreise  abgeschatzt.      Es  wird  eine 
opt imal-abs chat zende  Kreisarithmetik  entwickelt   sowie  eine  auf  dem 
Permanenzprinzip  aufbauende,    zentrierte  Kreisarithmetik  angegeben. 


Um  auch  mit  Mengen  reeller  oder  imaginarer  Zahlen  rechnen  zu 
kbnnen,  wird  die  Menge  der  komplexen  Kreise  eiveitert,  indem  Intervalle 
der  reellen  sowie  der  imaginaren  Achse  als  spezielle  Kreiszahlen 
aufgefasst  werden.   Dadiorch  kann  ausserdem  eine  fiir  achsenparallele 
Rechtecke  der  komplexen  Ebene  erklarte  Intervallrechnung  mit  Kreiszahlen 
nachvollzogen  werden. 

PEAK  73/2  1973  117  pages 


Approximation  durch  Intervallfunktionen 
by  R.  Krawczyk 

Die  bekannte  Appro ximat ions aufgabe,  eine  gegebene  Funktion  f(x) 
mit  Hilfe  eines  Fimktionensystems  zu  approximleren,  wird  erweitert.   Es 
wird  eine  Intervall funktion  (Funktion  mit  Intervallkoeffizienten)  derart 
bestimmt,  dass  die  zu  appro ximierende  Funktion  in  dem  diirch  die 
Intervall funktion  definierten  Streifen  liegt.   Diese  Methode  wird 
anschliessend  auf  den  diskreten  Fall  der  Ausgleichung  von  n   gegebenen 
F-unktionswerten  angewandt,  und  zwar  1.  mit  Hilfe  eines  Intervallpolynoms , 
2.  durch  eine  trigonometrische  Intervall funktion.   Insbesondere  wird  fur 
den  Spezialfall  der  Interpolation  die  Fehlerabhangigkeit  \intersucht .   Ftir 
eine  Anzahl  von  Beispielen  wird  derjenige  Grad  der  Ausgleichs funktion 
ermittelt,  fur  welchen  der  entsprechende  Streifen  am  schmalsten  ist . 

KARL  69/7  1969  12  pages 


On  the  Computation  of  Rigorous  Boirnds  for  the  Solutions  of  Linear  Integral 
Equations  with  the  Aid  of  Interval  Arithmetic 
by  C.  W.  Cryer 

A  method  is  given  for  approximately  solving  linear  Fredholm 
integral  equations  of  the  second  kind  with  non-negative  kernels.   The  basis 
of  the  method  is  the  construction  of  piecewise-polynomial  degenerate  kernels 
which  bound  the  given  kernel.   The  method  is  a  generalization  of  a  method 
suggested  by  Gerberich.   When  implemented  on  a  computer,  interval  arithmetic 
is  used  so  that  rigorous  bounds  for  the  solution  of  the  integral  equations 
are  obtained. 

The  method  is  applied  to  two  problems:   the  equation  considered 
by  Gerberich;  and  the  equation  of  Love  which  arises  in  connection  with  the 
problem  of  determining  the  capacity  of  a  circular  plate  condenser. 

WIS  70  1969  ^0  pages 


Iterationsverfahren  in  halbgeordneten  Raumen 
by  R.  Krawczyk 

In  der  vorliegenden  Arbeit  werden  Iterationsverfahren  zur 
Berechnung  einer  Folge  von  Intervallen  in  halbgeordneten  linearen  Raumen 


"behandelt.   Es  verden  atstrakte  Satze  ziir  Einschliessung  xind  Existenz  einer 
Losung  einer  Operatorgleich-ung  imd  zur  Konvergenz  der  Intervallfolgen 
formuliert.   Im  zvelten  Tell  dieser  Arbeit  warden  diese  Satze  aui*  eine 
Anzahl  von  Beispielen:   Losung  einer  Gleichimg,  N-ullstellenbestiimnung  einer 
analytischen  F-unktion,  Eigenvert-  und  Eigenvektorbestimmung  von  Matrizen, 
Integralgleichung  angewandt. 

KARL  70/2  April  1970  30  pages 


Bibliography  on  Proving  the  Correctness  of  Computer  Programs — Addition  No.  1 
by  Ralph  L.  London 

The  continued  research  activity  in  proving  the  correctness  of 
computer  programs  and  the  widespread  interest  in  my   previous  program  proving 
bibliography  (London  1970a)  encourage  me  to  compile  these  additional  updating 
citations.   The  selection  criteria  remain  essentially  unchanged;  only  the 
form  of  the  citation  is  trivially  changed.   As  before,  I  wo"uld  be  most 
interested  in  learning  of  corrections  and  additional  citations  to  update 
matters. 

WIS-10i|  December  1970  8  pages 


FUNCTION   EVALUATION  AND   COMPLEXITY  THEORY 


Computational   Complexity  of  One-Point   and  Multipoint    Iteration 
by   H.    T.    Kung  and  J.    F.    Traub 

Let    (|)  "be   an   iteration   for    ^proximating  the   solution   of  a  problem 
f.      We   define  a  new  efficiency  measure   e((|),    f).      For  a  given  problem  f, 
we   define  the  optimal   efficiency  E(f)    and  establish  lower  and  upper  boimds 
for  E(f)  with   respect   to   different   families  of  iterations.      We  conjecture 
an  upper  bound  on   E(f)    for  any   iteration  without  memory. 

CMU  No   #  April   1973 


Fast   Evaluation   and   Interpolation 
by   H.    T.    Kung 

A  method   for   dividing  a  polynomial   of  degree    (2n   -  l)   by   a  pre- 
computed  nth   degree  polynomial   in  0(n  log  n)   arithmetic  operations    is   given, 
This    is    used  to  prove  that  the   evaluation  of  an   nth   degree   polynomial    at 
n+1   arbitrary  points    can  be   done   in  0(n  log     n)    arithmetic   operations,    and 
consequently,    its   dual  problem,    interpolation  of  an  nth   degree  polynomial 
from  n+1   arbitrary  points   can  be  performed  in  0(n  log     n)   arithmetic 
operations.      The  best   previously  known  algorithms   required  0(n  log     n) 
arithmetic   operations. 

CMU  Wo   #  January  1973 


Optimal  Order  of  One-Point   and  Multipoint   Iteration 
by   H.    T.    Kung  and  J.    F.    Traub 

The  problem  is   to   calculate   a  simple   zero   of  a  non-linear   function 
f  by   iteration.      We   exhibit    a  family  of  iterations  of  order  2  which   use 

n  evaluations   of  f  and  no   derivative   evaluations,    as  well   as   a  second  family 
of  iterations   of  order  2  based  on  n  -  1   evaluations   of  f  and  one  of  f. 

In  particular,   with   four  evaluations  we   construct   an   iteration  of  eighth 
order.      The  best   previous    result    for   four  evaluations  was   fifth  order. 

We  prove  that   the  optimal  order  of  one   general   class  of  multipoint 
iterations    is   2  and  that   an   upper  bound  on  the  order  of  a  multipoint 

iteration  based  on  n  evaluations   of  f    (no   derivatives)    is   2    . 

CONJECTURE.      A  multipoint   iteration  without   memory  based  on  n 
evaluations   has   optimal   order  2 

CMU   No    #  February   1973 


The  Computational   Complexity  of  Algebraic  Numbers 
by  H.    T.    Kung 

Let   {x.}  be  a  sequence  approximating  an   algebraic   n-umber  a   of 

degree  r,    and  let   x.  ,^    =    tf)(x.,x.    ^,...,x.     -,.,),    for  some   rational   fimction   4 
"  1+1  1      1-1  i-d+1  ^ 

with   integral   coefficients.      Let  M  denote  the  number  of  miiltipli  cat  ions   or 
divisions  needed  to   compute      (^  and  let  M  denote  the  number  of  multiplications 

or   divisions,    except  by   constants,   needed  to   compute      <^.      Define  the  multipli- 

loggP  loggP 

cation  efficiency  measure  of  {x. }  as  E({x  })=  — — — or  as  E({x. })  =  — - —  , 

1  1    '  M  1  M 

where  p   is   the  order  of  convergence  of  {x.}.      Kung   [l]   showed  that 
E({x.  })    <_  1   or  equivalently,   M  >_  log  p.      In  this   paper  we   show  that 
(i)  M  >_  log2[r([pl-l)   +  1]   -  1;    (ii)    if  E({x.})   =  1  then  a    is   a  rational 
number;    (iii)    if  E({x.})   =  1  then  a   is   a  rational  or  quadratic   irrational 
niimber.      This   settles   the  question  of  when  the  multiplication  efficiency 
E({x.})   or  E({x.})   achieves   its  optimal   value  of  unity. 

CMU  No    #  March  1973 


Diagonal  Theorems    for  Random  Access   Machines 
by  Stephen  A.    Cook  and  Robert   A.    Reckhow 

Turing  Machines  have  often  been   criticized  for  not  being  good  models 
for  real   computing  machines.      In  this   report  we   describe  the  RAM,    an   abstract 
model  of  a    (fixed-program)   random  access    computer.     A  unique   featvire  of  the 
RAM  is  that   the  execution  time  of  an  instruction  depends  on  the  size  of  the 
numbers  being  manipulated.      We  then  describe-  RAM-ALGOL,    an  ALGOL  60-like 
programming  language   for  RAM's.      This   language  helps   to   clarify   constructive 
proofs  of  theorems    involving  RAM's.      Using  RAM-ALGOL  programs  we  show  that 
the  computing  speeds   of  fixed-program  and  stored-program  random  access  machines 
and  Turing  Machines   are  not  too  widely   divergent. 

Our  main  result   states  that   if  T2(n)    is   a   function   such  that   there   is 
a  RAM  that   computers   T2(n)   in  time  0(T2(n)  j,    and  if  T-]_(n)    is   any  function 

inf  ^1^^) 
such  that  7;r-7 — r  =  0    ,      then  there  is   a  set   S  that   can  be   recognized  by 

n-x»  T2(n)  '  ?=  j' 

some  RAM  in  time  0(T2(n))  but   no  RAM  recognizes   S   in  time  0(T-j_(n)).      This    is 
a  sharper  diagonal  res\ilt   than  has  been  obtained  for  Tioring  Machines. 


TOR-1+2  J-une  1972  ll^l 


pages 


APPROXIMATION 


Korovkin  Sets    (Sets   of  Convergence) 
by    G.    G.    Lorentz 

This    report   treats    sets    of  convergence   of  positive  operators, 
and  of  contractions,    on  the   space  of  continuoTis    fiinctions,    and  on   other 
Banach   function  spaces.      Chapter   3  of  the  report    is    entirely  new,  while  the 
other  two   chapters   present   the   existing  theory   in  a  new   and  more  general 
setting. 

CNA-59  September  1972 


An  Application  of  the   Theory   of  Approximation  by  Families   with    a  Fixed  Point 
by  G.    G.    Belford 

Recently   developed  theorems   characterizing  best   uniform 
approximations    from  a  family  with   a  fixed  point   are   shown  to  be   useful   in 
the   estimation  of  errors   in  computational  techniques    for  solving  linear 
algebraic   equations.      Specifically,    a  gap   in  the  proof  of  a  published 
theorem  is    filled  in. 

CAC   TM  No.    11  May  1973  6  pages 


Simultaneous    Fitting  of  Exponential  Decay    Curves 
by   G.    G.    Belford 

This   paper   deals  with   characterization  of  best   approximations  to 
vector-valued  functions.      The  approximations    are  themselves   vector-valued 
functions   with   components   depending  nonlinearly  on  the  approximation  para- 
meters.     The  constraint   is    imposed  that    certain  of  the  parameters   should  be 
identical   for  all   components.      An  application  to   exponential   approximation 
is    discussed  in   some   detail. 

CAC   No.    6l  April  1,    1973  30   pages 


The    Cholesky  Factorization    for  Derivative-Free   Nonlinear   Least   Squares 
by  Richard  H.    Bartels 

In  a  previous  technical   report  the   author  presented  an   algorithm 
for  minimizing  sums   of  squares   of  nonlinear   functions    in   several   variables 
without   the  use  of  derivatives.      A  subsection  of  this    algorithm  required  that 
the  least-squares   solution  to   an  overdetermined  linear  system  be   found.      The 
implementation  which  was   presented  in  the  report   accomplished  this   via  the 
QR   factorization  of  the  system's  matrix.      However,    if  the  number  of  functions 
in  a  nonlinear  least-squares  problem  greatly  exceeds  the  number  of  variables 
involved,    the  matrix  Q  of  the   factorization  requires   a  disproportionate 
amount   of  storage  space.      To  overcome  this  we  present   an  alternate   imple- 


mentation   In  which  the  linear  least-squares   subproblem  is   solved  via  the 
Cholesky   factorization  of  the   normal   equation.      A  FORTRAN  program  -with  test 
results   is   included. 

CM-6i|  March  1973  Program  Incl. 


Constructive  Aspects   of  Discrete  Polynomial  Spline  Functions 
by  L.    L.    Schumaker 

Discrete  polynomial   splines   are  vectors    consisting  of  pieces  of 
polynomials   tied  together  on  knot   intervals.      They  arise  in  optimal   siammation 
formulae  and  are  expected  to  have  applications  to   approximate   solution  of 
discrete  operator  equations.      Here  ve  obtain  representations   and  local 
Support  bases    (with  recursions   for  them),    discuss  the  total   posit ivity  of  a 
fundamental   Green's   function,    and  give  certain  basic  interpolation  resiilts. 

CNA-62  January  1973  I8  pages 


On  the   Convergence  of  Cubic   Interpolating  Splines 
by   Tom  Lyche  and  L.    L.    Schumaker 

Given  a  sequence  of  partitions   A     =    (O  =  x  <x^<...<x     =  l)   and  a 

n  o     1  n 

corresponding  sequence  of  cubic   spline  projections   P    ,  we   find  properties   of 

A     which   guarantee  that        f  -  P   f     -K)   as   n->°°  for  arbitrary   continuous 
n  '  '  n    '  ' 

functions   on    [O,   l].      Results   are  obtained  for  cubic  natural   and  cubic   Type-I 
spline   interpolation. 

CNA-61  September  1972 


Computation  of  g-Splines  Via  a  Factorization  Method 
by  Harold  D.    Eidson  and  L.    L.    Schumaker 

Fortran  subroutines   are  presented  for  the  purpose  of  computing  and 
evaluating  g-splines   interpolating  Hermit e-Birkhoff  data.      The   subroutines 
are  based  on  a   factorization  method  for  computing  g-splines   discussed  by 
Munteanu  and  Schumaker   (CNA  25,    Center   for  Numerical  Analysis,   UT  Austin,   1971) 

CNA-60  September  1972  Program  Incl. 


Uber  A-usgleichs-Splines 
by  Klaus  Bohmer 

Combining  the  intrinsic  properties   of  splines   and  the  method  of 
least   squares  we   discuss   an  extremal  problem.      We-show  the  existence -of  a 


solution  and  give  the   conditions   for  the  uniqueness.      For  g  -^  0  resp.    g  ->- 

we  receive  the  usual  interpolation   spline  resp.    a  solution  of  a  problem 

minimizing  a  sum  of  squares.      We   conclude   in  characterizing  the  solutions 
for  EHB- Interpolation  problems. 

KARL  71/5  September  1971  11  pages 


On  Best   Simultaneoiis  Approximation   in  Normed  Linear   Spaces 
by   D.    S.    Goel,    A.S.B.    Holland,    C.    Nasim,    and  B.    N.    Sahney 

Let   S  be  a  non-empty   family  of  real   valued  continuous    functions   on 
[a,    3].      Diaz   and  McLaughlin    [l],    [2],    and  Dunham  [3]  have   considered  the 
problem  of  simultaneously   approximating  two   continuous   functions   f     and  f 
by   elements   of  S.      If    | |    •    | |    denotes   the  supremum  norm,   then  the  problem  is 
to   find  an   element   s*   e  S,    if  it   exists,    for  which 

max    ( I  I f     -   s* I  I ,     I  I f     -    s* I  I )    =   inf  max    ( |  | f     -   s |  | ,    |  | f     -   s  |  | ) . 

s    e    S 
The   above  problem  is   studied  in   general  normed  linear  spaces. 

CAL-186  March  1973  7  pages 


Best  Approximation  by   a  Saturation   Class  of  Polynomial   Operators 
by  D.    S.    Goel,    A.S.B.    Holland,    C.    Nasim  and  B.    N.    Sahney 

In  this   paper  we  prove  that  a  method  of  summation  involving  Norlund 
operators   is   saturated  with  the  order  Pn  and  related  resiolts. 

Pn 

CAL-191  June  1973  10  pages 


Characterisation  of  an  Element   of  Best   1   -Simultaneous  Approximation 
by  D.    S.    Goel,   A.S.B.    Holland,    C    Nasim,    and  B.    N.    Sahney 

Let   X  be  a  normed  linear  space  and  K  a  subset  of  X.      In  CAL-186 
we  have   considered  the  problem  of  best    simiiltaneous   approximation  of  two 
elements   xi,X2   e  X  from  the  elements   of  K. 

The  object   of  the  present  paper   is  to   give   a  characterisation  of 
an   element   of  best   simultaneous   approximation  under  a  more  general   definition 
of  simultaneous   approximation. 

CAL-188  May  1973  6  pages 


Splines  with   Non-Negative  B-Spline  Coefficients 
"by  C.    de  Boor  and  James   W.   Daniel 

We  consider  the  question  of  the  approximation  of  non-negative 
functions  by  non-negative  splines   of  order  k    (degree  <  k)    compared  with 
approximation  by  that   subclass  of  non-negative  splines   of  order  k   consisting 
of  all  those  whose  B-spline  coefficients   are  non-negative;   while   approximation 
by  the  former  gives   errors  of  order  h-^,    the  latter  may  yield  only  h^.      These 
results   are  related  to   certain  facts   about   quasi-interpolants. 

CNA-65  March  1973  5  pages 


The  Continuity  of  Metric  Projections    as   Functions  of  the  Data 
by  James  W.    Daniel 

Let  X  be   a  Hilbert    space,    and  consider  the  point   xq  minimizing, 
for  a  given   f  in  X,   the   distance    | |x  -   f | |    as   x  ranges  over  a  polyhedral   set 
C   defined  by  a  finite  niomber  of  real -valued  equalities   and  inequalities.      We 
w^sh  to   see  how  xq  varies  when   f  and  C   vary.      It   is    easy  to   see  that   xq   is 
Holder  continuous  with  exponent  1/2   in  its  dependence  on  these  parameters; 
this   estimate  is   in  general  sharp.      We  show,   however,   that   in  certain  cases 
XQ   is   actually  Lipschitz   continuoiis   in  its   dependence  on  the  parameters  which 
are  used  to  define  the  set  C. 

CNA-68  April  1973  9  pages 


LINEAR  ALGEBRA. 


A  Fast   Method  for  Solving  a  Class   of  Tri-Diagonal  Linear  Systems 
"by  Michael  A.    Malcolm  and  John  Palmer 

The   solution  of  linear  systems  having  real,    symmetric,    diagonally 
dominant,   tri diagonal   coefficient  matrices  vith   constant   diagonals   is 
considered.      It   is  proved  that   the   diagonals  of  the  LU  decomposition  of 
the   coefficient   matrix  rapidly   converge  to   full   floating-point  precision. 
It   is   also  proved  that  the  computed  LU  decomposition   converges  when  floating- 
point  arithmetic   is   used  and  that  the  limits   of  the  LU  diagonals   using 
floating  point   are  roughly  within  machine  precision  of  the  limits   using  real 
arithmetic.      This    fact   is   exploited  to  reduce  the  niimber  of  floating-point 
operations   required  to   solve  a  linear  system  from  8n-7  to   5n+2k-3,  where  k 
is  much  less   than  n,   the  order  of  the  matrix.      If  the   elements  of  the   sub- 
and  super  diagonals   are  1,    then  only   i+n+2k-3  operations    are  needed.      The 
entire  LU  decomposition  takes   k  words  of  storage,    and  considerable  savings 
in   array  subscripting  are  achieved.      Upper  and  lower  boxinds   on  k   are  obtained 
in  terms  of  the  ratio  of  the  coefficient  matrix  diagonal  constants   and  para- 
meters  of  the   floating-point  number  system. 

Various   generalization  of  these  results   are   discussed. 

STAU-CS-T2-323  November  1972  l6  pages 


Iterative  Solution  of  Tridi agonal   Systems  on  Parallel   or  Vector  Computers 
by  J.    F.    Traub 

We  study  the  iterative  solution  of  a  tridiagonal  linear   system  of 
size  m  on   a  parallel  or  vector  computer.      Such   systems   arise  commonly  in 
the  numerical   solution  of  partial   differential   equations. 

The  Gauss   algorithm  takes   time  linear  in  m.      We   introduce   a 
Parallel   Gauss   iteration  and  show  it   can  be  used  to   solve  a  tridiagonal 
system  in  time   independent   of  m.      Furthermore,   the  error  norm  is   reduced  at 
each    iteration   step.      A  Parallel  LP  decomposition   is   also   defined. 

Parallel   Gauss   is  based  on    "multiplicative   splitting".      We   intro- 
duce parallel   algorithms  based  on   "additive  splitting".      These   are   Jacobi, 
JOR,   Parallel   Gauss-Seidel,    and  Parallel   SOR. 

We   compare  these  parallel   algorithms   on   a  model   problem  and 
conclude  that  JOR,    Gauss-Seidel,    and  SOR  are  not   competitive.      Jacobi    is  best 
if  there   is   a  "large   amount"  of  diagonal   dominance  while  Parallel   Gauss   is 
best   if  there   is   only    "limited"    diagonal   dominance. 

CMU  No   #  January  1973  ^2  pages 


10 


Methods   for  Modifying  Matrix  Factorizations 

ty  P.    E.    Gill,    G.    H.    Golub,   ¥.    Murray,    and  M.   A.    Saunders 

In  recent     years   several   algorithms  have  appeared  for  modifying 
the   factors   of  a  matrix  following  a  rank-one  change.      These  methods  have 
always  been  given   in  the  context  of  specific   applications   and  this  has 
probably   inhibited  their  use  over  a  wider  field.      In  this   report   several 
methods   are   described  for  modifying  Cholesky   factors.      Some  of  these  have 
been  published  previously  while  others   appear  for  the   first   time.      In  addition, 
a  new  algorithm  is  presented  for  modifying  the  complete  orthogonal   factor- 
ization of  a  general  matrix,    from  which  the  conventional   QR   factors   are 
obtained  as   a  special   case.      A  uniform  notation  has  been  used  and  emphasis 
has  been  placed  on   illustrating  the   similarity  between  different   methods. 

STAN-CS-72-322  November  1972 


Modifying  Pivot   Elements   in  Gaussian  Elimination 
by   G.    ¥.    Stewart 

The   rounding-error   analysis  of  Gaussian   elimination  shows   that  the 
method  is   stable  only  when  the  elements   of  the  matrix  do  not   grow  excessively 
in  the  course  of  the  reduction.      Usually  such   growth   is  prevented  by  inter- 
changing rows   and  columns   of  the  matrix  so  that   the  pivot   element   is 
acceptably   large.      In  this  paper  the  alternative  of  simply   altering  the  pivot 
element   is   examined.      The  alteration,  which   amounts  to   a  rank  one  modification 
of  the  matrix,    is   undone   at   a  later  stage  by  means   of  the  well-known   formula 
for  the  inverse  of  a  modified  matrix.      The  technique   should  prove   useful   in 
applications    in  which  the  pivoting  strategy  has  been   fixed,    say  to  preserve 
Spars eness   in  the  reduction. 

CMU  No   #  March  1973 


The  SAC-1  Polynomial  Linear  Algebra  System 
by  G.    E.    Collins   and  M.    T.    McClellan 

This   system  is  the  tenth   in  a  series  of  subsystems    comprising 
the   SAC-1   System  for  Symbolic  and  Algebraic  Calculation.      The  present   sub- 
system consists  of  programs    implementing  modular  algorithms    for  linear 
equations   solution,   matrix  inversion,    determinant   calculation,    null   space 
basis   generation,    and  matrix  miiltipli cation,    all   for  matrices  with   integer 
or  polynomial   entries.      For  each  program  in  the  system  is   given  a  fimctional 
specification,    an  algorithm  description,    an   analytical   computing  time,    and  a 
Fortran  program  listing.      Empirically  observed  computing  times   for   some  of 
the  key  programs   are  presented.      Also,    a  test  program  is    supplied  as    an  aid 
in   implementing  the  system  and  to   illustrate  its   use. 

WIS-15^  April  1972  Program  Incl . 


11 


A  Determinant   Theorem  with  Application  to  Parallel  Algorithms 
"by   Don  Heller 

We  state  and  pix)ve  an  expansion  theorem  for  the   determinant  of  any 
Hessenherg  matrix.      The  expansion  is    expressed  as   a  vector-matrix-vector 
product  which   can  he   efficiently  evaluated  on   a  parallel  machine.      We   con- 
sider the   computation  of  the   first   N  terms   of  a  sequence  defined  by   a  general 
linear  recurrence.      On  a  sequential  machine  this  problem  is   0(N'^),  with  N 
processors   it    is   0(N),    and  with   0(N    )   processors   it   is   O(log^N)    using  our 
expansion.      Other  applications    include  locating  roots  of  analytic   functions 
and  proving   doubling   formulas   for  linear  reciorrences  with   constant   coefficients. 

CMU  No   #  March  1973 


On   a  Characterization  of  the  Best    I     Scaling  of  a  Matrix 
by  G.    H.    Golub   and  J.   M.    Varah 

This   paper  is    concerned  with  best  two-sided  scaling  of  a  general 
square  matrix,    and  in  particular  with   a  certain  characterization  of  that  best 
scaling:      namely  that  the  first   and  last   singular  vectors    (on  left   and  right) 
of  the  scaled  matrix  have  components   of  equal  modulus.      Necessity,    sufficiency, 
and  its   relation  with  other  characterizations   are   discussed.      Then  the  problem 
of  best   scaling   for  rectangular  matrices   is    introduced  and  a  conjecture  made 
regarding  a  possible  best   scaling.      The  conjectiore   is   verified  for  some 
special    cases. 

STAN-CS-T2-319  October  1972 


The  LU-Factorization  of  Totally   Positive  Matrices 
by    Colin   W.    Cryer 

An  n  X  n  real  matrix  A   is   an   STP    (strictly  totally  positive)   matrix 
if  all   its   minors    are  strictly  positive.      An  n   x  n  real  triangular  matrix  A 
is   a  ASTP  matrix  if  all   its  non-trivial  minors   are  strictly  positive.      It    is 
proved  that   A   is    an   STP  matrix  iff  A  =  LU  where  L   is   a  lower  triangular  matrix, 
U  is   an  upper  triangiolar  matrix,    and  both  L  and  U  are   ASTP  matrices.      Several 
related  results   are  proved.      These  results  lead  to   simple  proofs   of  many  of 
the   determinantal  properties   of  STP  matrices. 

WIS-131  December  1971  23  pages 


Convergent   Generalized  Monotone   Splitting  of  Matrices 
by   0.    L.    Mangasarian 

Let   B  and  T  be  n  x  n  real   matrices   and  r  an  n-vector  and  consider 
the  system  u  =   BTu  +   r.      A  new  sufficient    condition   is    given   for  the   existence 


12 


of  a  solution   and  convergence  of  a  monotone  process  to   a  solution.      The  mono- 
tone process   is   a  generalization  of  the  Collatz-Schroder  procedure. 


WIS-105 


December  1970 


11  pages 


Monotone   Splitting  of  Matrices 
hy  0.-  L.   Mangasarian 

Given  the  iterative   scheme   x         =  BT  x     +  r  where  B,    T  are   fixed 

n  X  n  real  matrices,    r  a  fixed  real  n-vector  and  x     a  real  n-vector  we 

investigate  the  convergence   and  monotonicity  of  schemes  of  the  type 


V 


i+1 


w 


i+1 


•^ 

B 

0 

0 

B 

-\ 

— •                             — < 

r      ~] 

^11 

-^12 

1 

V 

+ 

r 

^21 

S22_ 

i 
w 

r 

where  S.  ,    are  n  x  n  real  matrices   related  to  T.      The  n-vector  iterates   v   ,w 
bracket   in  a  certain  sense  solutions   x  of  x     =  BTx+r.      We  also   give  necessary 
and  sufficient   conditions    for  the  monotonicity  of  the  original    iterative 
scheme  itself  x         =  BTx     +  r.      This  leads  to   monotonicity  results    for 
classicial   Iterative  schemes    such   as  the  Jacobi,    Gauss-Seidel   and  successive 
overrelaxation  methods. 


WIS-106 


December  1970 


19  pages 


Zeros   of  X-Matrices,    A  Survey 
by  Jon  Rokne 

We  present   a   survey   of  results   for  computing  zeros   of  X-matrices 
and  matrix  polynomials.      Most   of  the   results   are  not  new,    except   for  the 
results    in   section  3.      The  results  that   are  collected  here   do   not   seem  to 
"be  known  to   a  large  audience,   however. 


CAL-181 


March  1973 


17  pages 


13 


Characterizations  of  Real  Matrices  of  Monotone  Kind 
by   0.    L.    Mangasarian 

An  m  by  n  real  matrix  A  is   said  to  be  of  monotone  kind  if 

(l)  Ax  ^  0  ■    ■>      x^O    . 

Collatz  treats   square  matrices  of  monotone  kind  and  shows  that    for   such 
matrices  the  above   implication   is   equivalent  to:      A        exists    and  A~l   >_  0. 

It    is  the  piorpose  of  this  note  to   generalize   Collatz 's   result   to 
rectangular  matrices,    and  also   to   show  that,    for  the   general   rectangular 
case,    a  matrix  of  monotone  kind  can  be   further  characterized  as  one   for 
which  the  convex  conical   hull   of  the   rows   contains  the  nonnegative  orthant. 

WIS-15  February   1968  8  pages 


A  Linear  Programming  Implementation 
by  Jonathan  Lermit 

This    document    discusses  the   implementation  of  a  recently   developed 
version  of  the   simplex  method  for  linear  programming  using  Cholesky 
factorization    (where  the  basis    is    expressed  as   a  product   of  a  lower  tri- 
angular and  an   orthogonal  matrix)    rather  than  the  more  usual  product   form  of 
the   inverse.      Storage  schemes   for  the  resulting  lower  triangular  matrix 
suitable   for  an   array  processor    (the  orthogonal  matrix  is   not   retained)   and 
necessaiy  adaptations  to  the   algorithm  when  the   constraint  matrix  is 
expressed  as    a  linear  operator  are   also   discussed. 

CAC  No.    h6  May   7,   1973  30  pages 


Fehlerabs chat z long  reeller  Eigenwerte  und  Eigenvektoren  von  Matrizen 
by  R.    Krawczyk 

Reelle   einfache   Eigenwerte  und  die   dazugehorigen  reellen  Eigen- 
vektoren einer  quadratischen  Matrix  werden  mit   Hilfe   einer  Intervallarithmetik 
\anter  Berucksichtigung  aller  Run  dungs  fehler  abgeschatzt.      Fur  diese  Fehler- 
abschatzTing  benbtigt   man   als  Daten   die   Nah  e  rungs  we  rte   eines   Eigenwertes   und 
des   entsprechenden  Eigenvektors ,   welche  man  sich   nach   irgendeinem  numerischen 
Verfahren  verschafft  hat.      Als    ergebnis    erhalt   man  ein  Intervall   und  einen 
Intervallvektor,   welche  den  exakten  Eigenwert  bzw.      den  exakten  Eigenvektor, 
enthalten.      Gleichzeitig  ergibt   sich   daraus    auch   die  Existenz   eines   reellen 
Eigenwertes . 

KARL  68/5  March   1968  15  pages 


Verbesserung  von  Schranken   fur   Eigenwerte  und  Eigenvektoren  von  Matrizen 
by  R.    Krawczyk 

Es   wird  ein  Verfahren  beschrieben,   wie  man   die  Fehlerschranken 
eines   Eigenwertes   und  des   zugeordneten  Eigenvektors   einer  Matrix  mit   Hilfe 

lU 


elner   Intervallarithmetik  verbessern  kann.      Dabei  wird  dem  komplexen  Eigen- 
wertproblem  n-ter  Ordnung  ein  reelles  nichtlineares   Gleichungssystem  der 
OrdnTong  n+2   zugeordnet,    so   dass  nur  ein   geringer  Mehraufwand  an  Rechenarbeit 
im  Vergleich   zur  Einschliessung  reeller  Eigenwerte   erforderlich   ist.      Die 
Konvergenz   der  Iterationsfolge  hangt   im  wesentllchen  von  den  Anfangs-Schranken 
des   Eigenwertes   imd  nicht   von  den  Schranken   des   Eigenvektors   ab. 

KARL  69/5  April  I969  8  pages 


Einschrankung  von  Eigenwerten  reellsymmetrischer  Matrizen 
by  Oswald  Kreg 

Im  folgenden  wird  ein  Algorithmus   angegeben,    der  ausgehend  von 
einem  Einschliegungssatz   von  Collatz    die  Einschliegung  von  Eigenwerten   einer 
reellsymmetrischen  Matrix  A  leistet. 

Ntunerische  Schwierigkeiten ,    die   auftreten  konnen,   wenn   die  vorge- 
gebene  Waherung  z   fur  einen  Eigenvektor  Komponenten  enthalt ,    die  Null  oder 
sehr  klein  sind,   werden  durch   eine  Ahnlichkeitstransformation  beseitigt. 

KARL   70/10  August   19T0  2U  pages 


NONLINEAR  EQUATIONS 


The  Convergence  of  Multipoint   Iterations   to  Multiple   Zeros 
"by  G.    W.    Stewart 

This   paper  fills   a  gap   in  the  theory  of  multipoint   iteration   func- 
tion exemplified  by  the  question:      how  does  the   secant  method  converge  to   a 
mioltiple   zero.      A  general  theory  of  the  linear  convergence  of  multipoint 
iterations    is    developed,    and  it   is   shown  that   two  broad  classes  of  iterative 
methods    fit  this   theory-      The  results   of  numerical   investigations  based  on 
the  theoiy   suggest  that  Muller's  method  applied  to   a  multiple   zero  will 
inevitably  produce   complex  iterates. 

CMU  No.#  Januaiy  1973 


Some   Iterations    for  Factoring  a  Polynomial   II.      A  Generalization  of  the 
Secant  Method 
by  G.   ¥.    Stewart 

This   paper   describes   an   iterative  method  for   factoring  a  polynomial 
that  bears  the  same   relation  to   Bairstow's   method  as  the  secant  method  in  a 


15 


single  variable  bears  to  Newton's  method.      Like  the  secant  method,   the 
generalized  secant  method  requires   only  one   function  evaluation   for  each 
iteration,    and  like  the  secant  method  it    converges  to  a  simple   factor  with 
order    (l+/5")/2. 

CMU  No.    #  February  1973 


A  Quadratically  Convergent  Lagrangian  Algorithm  for  Nonlinear  Constraints 
by  J.    B.    Rosen  and  J.    L.    Kreuser 

An   algorithm  for  the  nonlinearly   constrained  optimization  problem 
is   presented.      The  algorithm  consists   of  a  sequence  of  major  iterations 
generated  by  linearizing  each  nonlinear  constraint   about  the   current  point, 
and  adding  to  the  objective  function   a  linear  penalty   for  each  nonlinear 
constraint.      The  resulting  fimction  is   essentially  the  Lagrangian.      A 
Kantorovich-type  theorem  is   given,    showing  quadratic   convergence   in  terms   of 
major  iterations.      This   theorem  insures   quadratic   convergence   if  the  starting 
point    (or  any  subsequent  point)   satisfies   a  condition  which   can  be  tested 
using  computable  bounds  on  the  objective   and  constraint   functions. 

WIS-166  November  1972  33  pages 


QUADRATURE 


Computing  Integrals   Involving  B-Splines  by  Means   of  Specialized  Gaussian 

Quadrature  R-uLes 

by  J.    L.    Phillips   and  R.    J.    Hanson 

In  this  paper  a  technique   and  algorithm  are   given  to   efficiently 
compute   integrals   involving  products  of  splines    and  general    functions. 

Using  the  B-Splines   as  weighting  functions,   we  show  how  to   gener- 
ate  Gaussian   quadrature   rules    for   approximating  the   integrals. 

Tables   of  abscissas   and  weights,   together  with  procedures   for 
their  use,    are   given   for  the   important    special   case  in  which  the  interval 
breakpoints    of  the   B-Splines   are   equally   spaced. 

WSU-73001  1973 


16 


On  Weight  Functions  for  Chebyshev  Quadrature 
by  K.  Salkauskas 

The  Chebyshev  quadrature  problem  is  to  determine  real  k  and  real, 

distinct  t^   ,...,t    in  [0,  l]  such  that 
l,n      n,n 


(1.1)     /  w(t)f(t)dt  =  k   I     f(t.  ^),  V  f  e  P^,  n  =  1,2,...   . 
0  1=1      ' 


1 

I 
0 

Here  w  is   a  given  weight   function  that   is  normally  taken  to  be   non-negative 

on    [0,    l].      It   is  well  known  that   if  w  =   1,   the  problem  cajinot  be   solved  with 

real   {t        }^       when  n  =   8  or  n  >   9.      On  the  other  hand,    for   (l.l)  transfomied 
l,n   1=1 

to  the   Interval    [-1,   l],   Ullman   [5]   has    found  a  one-parameter  family  of  weight 
functions   of  the   form 

f^\                   1                       1  +  2at  111 

w(t)   =  2"Y72    '  2    '  1^'    -h    •> 

with  the  property  that   the  problem  has   solutions   for  all  n.      When  a  =  0, 
one   recovers  the   classical   Chebyshev  weight    function,    for  which  the  Gauss 
and  Chebyshev  quadrature   formulas   coincide. 

The  purpose  of  this  paper  is  to   show  that  weight    functions   for 
which  the  Chebyshev  problem  is   solvable  are   scarce   in  a  probabilistic   sense. 

CAL-1T5  January  1973  9  pages 


IT 


ORDINARY   DIFFERENTIAL  EQUATIONS 

Necessary   and  Sufficient   Criteria  for  A-Statility  of  Linear  Mijlti-Step 
Integration  Formulae 
by   Colin  W.    Cryer 

k  .  k 

Let   p(^)   =     2      o' .    S     and  a(5)   =      I        3 .    C     "be  the   characteristic 
j=0     ^  j=0       J 

polynomials   of  a  linear  multi-step  method  for  the  n-umerical   solution  of  an 

initial   value  problem  for  ordinary   differential   equations.      It   is   shown 

that  the  method  is  A-stable  iff  all  the   following  conditions  hold: 

(i)    &     ^  0;    (il)   Re[p(C)a(?)J    >_  0   for    |c|    =1;    (iii)    P    and  a  satisfy  the 

root   condition,   that   is,   their  zeros  lie   inside  or  on  the  unit   circle   and 

any   zeros   on  the  unit   circle   are   simple.      For  the  case  when   p   and  a  have 

integer  coefficients,    a  program  has  been  developed  which   uses  the  SAC-1 

system   (system  for  Symbolic    and  Algebraic   Calculations,    version    (l)) 

determine  whether  the  multi-step  method   (p,a)    is  A-stable. 

WIS-IUT  March  1972  36  pages 


18 


A  Proof  of  the   Instability  of  Backward-Difference  Multistep  Methods    for 
the  Numerical   Integration  of  Ordinary  Differential   Equations 
by  Colin  ¥.    Cryer 

It   is   shown  that  the  backward  difference  m\iltistep  method 

I       i  V"^  y      =  hf 
m=l     ^  P  P 

for  the  numerical   integration  of  y'(x)   =   f(x,y)   is   stable   in  the   sense  of 
Dahlquist    iff  1   <_  q  <_  6. 

WIS-llT  May  1971  52  pages 


A  Note  on  the  Non-Exist  ence  of  Mult  lvalue 
A-Stable  Methods  of  Order  Greater  than  Two 
by   C.    ¥.    Gear 

It    is   shown  that  the  Dahlquist   result  limiting  the  order  of 
A-stable  multistep  methods   also   applies  to  multivalue  methods. 

UIUC-R-73-569  March  1973  7  pages 


The  Effect   of  Variable  Mesh   Size  on  the   Stability  of  Multistep  Methods 
by   C.    W.    Gear  and  K.   W.    Tu 

The   effects   of  two   different  techniques   for   implementing  variable 
mesh   sizes   in  multistep   formiiLas   are   investigated.      It   is   proved  that   one 
is  more  stable  than  the  other   for   some   cases,  but  that  both   are   stable  when 
the  step  changes   are  small.      The  practical   implications  of  these  results 
are   discussed. 

UIUC-R- 73-570  April  1973  35  pages 


Stability   and  Convergence  of  Variable  Order  Multistep  Methods 
by  C.   W.    Gear  and  D.    S.    Watanabe 

The   variable   step  Adam's  method  is   shown  to  be  stable   for  any 
order  changing  scheme.      The  Nordsieck   form  of  Adam's  method,   however,    is 
shown  to  be  stable  only   if  the  step  size   and  order  are   fixed  for  p  steps 
following  a  change  to   an  r-step  method,   where  p  is   r  or  r+1   depending  on 
the  algorithm  used  to   interpolate  the  necessary  high   derivatives.      Finally, 
general   consistent   and  strongly   stable  multistep  and  multivalue  methods   are 
shown  to  be   stable   if  the  method  is    fixed  for  a  certain  number  of  steps 
following  each  method  change   and  step  size  changes   are   small.      This  number 
is   independent  of  the   differential   equation   and  the  step  sizes. 

UIUC-R-73-571  May  1973  31  pages 

19 


Solutions  of  a  Differential  Equation  Arising   in   Chemical   Reactor  Processes 
"by  Seymour  V.    Parter 

Consider  the  boundaiy  value  problem  y"  +  — y'   +   Bf(y)   =  0, 

y'(0)   =   0,  y(  x)   =    T  where   B   >_  0,    t   >_  0.      The   function  f(y)    satisfies    certain 

properties   which  generalize  the  properties   of  '^^(j)   =   exp    (-  -i — r) .      We  are 

concerned  with  the  number  of  solutions   in  various   regions  of  the   t,    3  plane. 

WIS-162  January  1973  5^  pages 


Zxir  numerischen  Losimg  von  gewohnlichen  Differentialgleichungen  zweiter  Ordnung 
"by  Manfred  Heidt 

In  dieser  Arbeit  wird  ein  Verfahren  zur  numerischen  Berechnving 
einer  Faherungslosving  zusammen  mit   einer  Fehlerabschatzung  fiir  das 
An f an gswert problem 

y"(x)   =   f(x,y(x),y'(x)),   y(x^)    =  y^ ,  y'(x^)   =  y '^ 

einer  gewohnlichen   expliziten  Differentialgleichung  zweiter  Ordnung 
angegeben.      Es  handelt    sich  hierbei   um  ein  Einschritt verfahren.      Die 
Differentialgleichung  wird  bei   jedem  Integrationsschritt   lokal   linearisiert , 
die  linearisierte  Differentialgleichung  analytisch   gelost ,    diese  Losung  mit 
einem  Storansatz   abgespalten  und  nur  noch   eine   relativ  "harmlose"  Rest- 
differentialgleich-ung  numerisch   gelost.      Mit   Hilfe  einer  Defektabschatzung 
werden  anschliessend  Fehlerschranken  dieser  Naherung  berechnet. 

Das   Verfahren  liefert   fur  eine  KLasse  linearer  Differential- 
gleichungen die   exakte  Losung.      Das   Phanomen   der  numerischen   Instabilitat , 
wie   es  bei    den  meisten  Faheriingsverfahren  selbst   bei   stabilen  Anfangswert- 
problemen   zu  beobachten  ist,   tritt  hierbei   kaum  mehr  auf. 

KARL   71/6  1971  122   pages 


Investigation  of  One-Step  Methods    for  Integro -Differential   Equations 
t»y   Geneva  G.    Belford  and  Surender  Kumar  Kenue 

One-step  methods    for  solving  integro-differential   equations    are 
studied  from  the  point  of  view  of  desiring  that  the  method  give   good 
accuracy  when  the  true  solution   asymptotically  goes  to   zero.      A  test   equation 
is   proposed  and  absolute   stability   is   investigated. 

CAC  No.    75  May  1973  11   pages 


20 


High  Order  Finite  Difference  Solution  of  Differential  Equations 
by  Victor  Pereyra 

These  seminar  notes  give  a  detailed  treatment  of  finite  difference 
approximations  to  smooth  nonlinear  tvo-point  "boiindary  value  problems  for 
second  order  differential  equations.   Consistency,  stability,  convergence, 
and  asymptotic  expansions  are  discussed.   Most  results  are  stated  in  such  a 
way  as  to  indicate  extensions  to  more  general  problems.   Successive  extrapolations 
and  deferred  corrections  are  described  and  their  implementations  are  explored 
thoroughly.   A  very  general  deferred  correction  generator  is  developed  and  it 
is  employed  in  the  implementation  of  a  variable  order,  variable  (uniform)  step 
method.   Complete  FORTRAN  programs  and  extensive  numerical  experiments  and 
comparisons  are  included  together  with  a  set  of  U8  references. 

STAN-CS-T3-3^8     April  1973  86  pages       Program  Incl. 


PARTIAL  DIFFERENTIAL  EQUATIONS 


A  Conjugate  Gradient  Approach  to  Nonlinear  Elliptic  Boundary  Value  Problems 

in  Irreg-ular  Regions 

by  Richard  Bart  els  and  James  W.  Daniel 

A  version  of  the  conjugate  gradient  method  is  proposed  for  solving 
'discrete  approximations  to  nonlinear  elliptic  boundary  value  problems  over 
irregular  regions.   The  convergence  rate  is  usually  independent  of  the 
discretization,  but  each  step  requires  the  solution  of  a  Poisson  equation  on 
the  region;  thus  a  fast  Poisson  solver  yields  a  fast  method  for  the  general 
problem.   Details  are  given  for  the  standard  5-point  approximation  to  the 
differential  equation,  with  the  Poisson  equations  being  solved  by  the 
Buneman  algorithm  after  some  preprocessing;  numerical  examples  are  given. 

CNA-63 


Niomerical   Studies   of  Discrete  Vibrating  Strings 
by  A.    B.    Schubert    and  D.    Greenspan 

Discrete   string  vibrations   are   studied  by  means   of  a  new  two 
dimensional  model.      Linear   and  nonlinear  wave  motions   are  constructed  with 
equal   ease.      Conditions   and  problem  in  which  horizontal  motion  is 
particularly  noticeable   are  emphasized.      A  large  variety  of   computer  examples 
are   given. 

WIS-158  November  1972  76  pages 


21 


FIMC TIONAL  EQUATIONS 


The  Nimierical  Solution  of  Boundary  Value  Problems  for  Second  Order  Functional 
Differential  Equations  by  Finite  Differences 
by  Colin  W.  Cryer 

In  the  present  paper  we  consider  numerical  methods  for  computing 
the  solution  of  the  boundaiy  value  problem 

x(t)  =  g(t,x(t))  +  (Fx)(t),  0  <  t  <  1, 

x(0)   =  x(l)   =  0, 
where,    F:C[0,   l]  ^  C[0,   l],    and  g:R     ^  R    . 
WIS-127  June  1971  57  pages  Program  Incl. 


OPTIMIZATION 


Least   Squares   Computations  with   Two  Algorithms   for  the  Two-Multiply, 
Two-Add  Givens  Rotation 
by   R.    J.    Hanson 

Two  numerically   stable  algorithms    for  the   implementation  of  the 
two-multiply,    two-add  Givens  transformation   are   discussed.      An   application 
of  the  use  of  these  algorithms    is   given   for  the   problem  of  accumulating  and 
deleting  rows  of  data  from  a  least   squares  problem  in   a  stable   manner. 

The  construction  of  either  transformation   requires    essentially 
the   same   amount   of  work.      The   first   method   (which   is   not   due  to  the  author) 
requires   no   square  roots  but   may  require  rescaling  to   avoid  underflow  and 
overflow.      The   second  method  requires   one   square  root  per  transformation 
but  will   need  rescaling  less  than  half  as   often   as  the   first   method. 

WSU-73002  1973 


Second   and  Higher  Order  Duality   in  Nonlinear  Programming 
by  0.    L.    Mangasarian 

A   d-ual  problem  associated  with   a  primal   nonlinear  programming 
problem  is   presented  that    involves   second  derivatives  of  the   functions    con- 
stituting the  primal  problem.      Duality  results   are  derived  for  this  pair 
of  problems.      More  general    dual   problems   are   also  presented,    and  duality 
results    for  these  problems   are   also   given. 

WIS-159  October  1972  20  pages 

22 


Einschliepung  des  Minimalpunktes  einer  streng  konvexen  F-unktion  auf  elnem 
n- dimensional en  Quader 
by  Rainer  Dussel 

Gegeben  sei  eine  Funktion  <^:  R  ->  R.  Sie  sei  streng  konvex  in  R 
und  es  gelte  (f)eC2(R^).  Weiterhin  sei  ein  n-dimensionaler  achsenparalleler 
Quader  QOR^  gegeben  durch  Q  :=  ( [a_  ,sr  ], .  . .  ,  [a  ,a"  ]). 

Gesucht  ist  derjenige  Punkt  xeQ,  fur  den  gilt 


(j)(x)  =  Min  (t)(x)  . 
xeQ 


Man  nennt   xeQ  den  Minimalpunkt   von   (f)  bezuglich   Q.      Existenz   und 
Eindeutigkeit   eines   solchen  Minimalpunktes   sind  unter  den  getroffenen 
Voraussetzimgen  trivial    (siehe   dazu  Satz    3). 

Anzugeben   ist   ein  Verfahren  zur  numerischen  Bestimmung  von  x  und 
damit   von   (j)(x).      Da   ein   solches  Verfahren   in   der  Praxis  nach   endlich  vielen 
Schritten  abgebrochen  verden  mu3   und  da   i.    a.    die  Komponenten  von  x  und  die 
Zaiil    ^(x)    in  einem  Computer  nicht    exakt    darstellbar  sind,    stellt   sich 
■weiterhin   die  Frage  nach  Fehlerschranken  fur  eine  mit    diesem  Verfahren 
bestimmte   Naheriing  x  zu  x.      Man  kann   damit   das   oben  genannte  Problem 
umformulieren   zu: 

Gesucht    ist   ein  numerischer  Algorithmus    zur  Angabe   eines    "mog- 
lichst  kleinen"  Quaders 

[x]    e   I^(R)   mit    [x]CQ  und  xe:[x] 


und  eines    "moglichst   kleinen"   Intervalls 

$el(R)   mit    (|)(x)e$    . 
KARL  72/2  July  1972  69   pages 


Stability  of  the  Solution  of  Definite  Quadratic  Programs 
by  James  W.    Daniel 

This   paper  studies   how  the   solution  of  the  problem  of  minimizing 
Q(x)   =  jx^Kx  -  k^x  subject  to   Gx  £  g  and  Dx  =   d  behaves  when  K,   k,    G,^g,   D, 
and  d  are  perturbed,    say  by  terms~of  size   e,    assioming  that   K  is   positive 
definite.      It   is   shown  that   in  general  the  solution  moves  by  roughly   e   if 
G,    g,    D,    and  d  are  not  perturbed;   when  G,    g,   D,    and  d  are  in   fact   perturbed, 


23 


much  stronger  hypotheses  allow  one  to  show  that  the  solution  moves  "by 
roughly  e.   Many  of  these  results  can  be  extended  to  more  general,  non- 
quadratic,  functionals. 

CNA-58  September  1972 


The  Quadratic  Assignment  Problem 
by  George  B.  Purdy 

In  this  report  we  discuss  some  seemingly  reasonable  approaches  to 
the  quadratic  assignment  problem,  and  we  give  some  evidence  from  automata 
theoiy  that  the  problem  is  insoluble. 

CAC  No.  71         February  1973  1^+  pages 


Die  Anwendung  der  Methode  "Branch  and  Bound"  auf  ein  verallgemeinertes 
Knaps ackpr obi em 
by  Rudolf  Krawczyk 

Fur  ein  verallgemeinertes  Knaps ackproblem  mit  gegebener  Zielfunktion 
und  Restriktionen,  dessen  Lbsung  durch  boolesche  Variable  dargestellt  werden 
kann,  wird  eine  Losungsmethode  nach  dem  "Branch  and  Bound" — Prinzip  angegeben. 
Diese  Methode  wird  mit  Hilfe  eines  LSsungsbaumes  veranschaulicht  und  an  einem 
Beispiel  ausprobiert.   Augerdem  wird  ein  Algorithmus  zu  diesem  Verfahren  be- 
schrieben  und  in  der  algorithmischen  Sprache  ALGOL  programmiert . 

KARL  71/1  January  1971  21  pages       Program  Incl. 


21+ 


ROOT  FINDING 


Fehlerschranken  zu  Naherixngswerten  von  Polynomwurzeln 
by  Karl  Nickel 

Gegeben  seien  ein  Polynom  n-ten  Grades   und     n     komplexe  Nahe- 
runsverte   zu  den    (unbekannten)   Polynomwurzeln.      Es  vlrd  ein  Algorithmus 
beschrieben,    der  zu  jedem  Naherungsvert'  eine  Fehlerabschatzung  liefert. 
Das   Verfahren   ist    "konvergent"  und  besitzt   eine   gevisse    (schwache) 
Optimalitat.      Es  benbtigt   keinerlei   zus'atzliche   Informationen  uber  die 
exakten  Nullstellen  und  versagt  nie,    auch  night   im  Falle   von  mehrfachen 
Nullstellen  oder  von  Wurzelhaufen.      Der  Algorithmus  wird  durch   ein  Triplex- 
ALGOL   60-Programm  verwirklicht ,   vomit   auch  noch    die  unvermeidlichen 
Runkungsfehler  berucksichtigt  "werden. 

KARL  69/6  June  1969  22  pages  Program  Incl. 


Abbruchkriterien  und  Numerishche  Konvergenz 
by  K.    Nickel   and  K.   Ritter 

Es   sei      X     ->  X     eine  von   einem  Verfahren   erzeugte   Folge   zur 

Approximation  der  reellen   Zahl   x.      Es    sei      x   (L)      ein  mit   einer  L-ziffrigen 

Maschine   gewonnener  Naherungsvert      zu  x       mit   lim  x   (L)   =  x      .      Es  wird  em 

"  n      ,    n       n 

L-x» 

Abbrechkriterium  N(L)   angegeben  derart,  da3  es  geniigt,  bei  fester  Ziffer- 

nanzahl  L  allein  die  Werte   x  (Lj,  x-^  (L) , .  .  .  ,31^/^  v  (L)   zu  berechnen  und 

da6  unter  sehr  schvachen  Voraussetzungen 

L->o° 
ist,  d.h.  da3   x^^/_s(L)   "numerisch  konvergiert ". 

KARL  70/6  May  1970  11  pages 


Abbrechkirterium  fur  Iterationsverfahren 
tiy  Rudolf  Kravczyk 

Die  unendliche  Folge  x  des  allgemeinen  Iterationsverfahrens  zur 
Losung  einer  Operatorgleichung  x  =  Tx  in  einem  metrischen  Raum  vird  haufig 
durch  eine  endliche  Folge  x  approximiert,  velche  von  der  benutzten  Rechen- 
anlage  abhangt.   Es  vird  ein  Abbrechkriterium  angegeben,  velches  die 
"numerische  Konvergenz"  im  Sinne  von  [3]  garantiert. 

Dieses  Abbrechkriteritim  wird  auf  das  NEWTONsche  Verfahren  zur 
Los-ung  einer  Gleichung  im  Reellen  und  auf  eine  Lineare  Integral gleichung 
angevandt . 

KARL  70/12  September  1970  11  pages 

25 


GRAPH  ALGORITHMS 


Two   Upper  Bounds   for  the  Weighted  Path  Length  of  Binary  Trees 
"by   Jean  Louis    Pradels 

Rooted  binary  trees  with  weighted  nodes   are  structures   encountered 
in  many  areas,    such   as   coding  theory,    searching  and  sorting,    information 
storage  and  retrieval.      The  path  length   is   a  meaningful   quantity  which   gives 
indication  about  the  expected  time  of  a  search  or  the  length  of  a  code   for 
example.      In  this   paper,    two   sharp  boimds    for  the  total  path  length   of 
general  weighted  node  trees   are  derived. 

UIUC-R- 73-565  January  1973  1^  pages 


An  Efficient   Implementation  of  Edmonds '    Maximum  Matching  Algorithm 
by   Harold  Gabow 

A  matching  in  a  graph   is   a  collection  of  edges,   no  two  of  which 
share  a  vertex.      A  maximum  matching  contains  the   greatest   number  of  edges 
possible.      This   paper  presents   an  efficient   implementation  of  Edmonds' 
algorithm  for  finding  maximum  matchings.      The   computation  time   is  proportional 
to  v3,   where  V  is  the  number  of  vertices;    previous   algorithms  have  computation 
time  proportional  to  V^.      The   implementation  avoids   Edmonds'   blossom  reduction 
by   using  pointers  to   encode  the   structure   of  alternating  paths. 

STAN-CS-72-328  June  1972  68  pages  Program  Incl. 


Finding  the  Cliques  of  a  Graph 
by  George  B.    Purdy 

Auguston   and  Minker   [l]   presented  a  version  of  the  Bierstone 
algorithm  for   finding  the   set   of  cliques  of  a   finite  undirected  graph. 
(A  clique   is   a  maximal   complete   subgraph).      However  they   gave  no  proof  that 
their  algorithm  worked,    and  indeed  Mulligan  and  Cornell    [2]   pointed  out  that 
it  was  wrong.      Mulligan   in    [3]    described  his   PL/I  implementation  of  their 
modified  version  of  the  algorithm,   but   it   is   referred  to  there  as   a 
heuristic.      For  our   algorithm  we   include  a  proof  that   it  works. 

This   algorithm  is   clearly  well   suited  for  use  on   an   array  pro- 
cessor,   or  an  array  of  processors,   which  the  other  algorithms   are  not. 

CAC    m  No.   5  December  1972  8  pages  Program  Inc. 


26 


MISCELLANEOUS 


A  Universal   Random  Number  Generator 

"by  Michael  A.   Malcolm  and  Cleve  B.   Moler 

A  subroutine   for  generating  uniformly-distrituted  floating-point 
numbers   in  the   interval   [O,   l)   is  presented  in  ANSI  standard  Fortran. 
The   subroutine ,   URAND,    is   designed  to  be  relatively  machine  independent. 
URAND  has  undergone  minimal  testing  on  various   machines   and  is  thought  to 
work  properly  on  any  machine  having  binary   integer  number  representation, 
integer  multiplication  modulo     m     and  integer  addition   either  modulo     m 
or  yielding  at  least      £og    (m)      significant  bits,   where     m     is   some  integral 
power  of     2    . 

Upon  the   first   call  of  UMND,   the  value  of     m     is    automatically 
determined  and  appropriate  constants    for  a  linear   congruential   generator  are 
computed  following  the   suggestions  of  D.    E.    Knuth,   Volume  2.      URAND   is 
guaranteed  to  have  a  full-length   cycle.      Readers   are   invited  to   apply  their 
favorite  statistical  tests  to  URAND,   using  any  binary  machine,    and  report 
the  results  to  the   authors. 

STAN-CS-T3-33^  January  1973  Program  Incl. 

Computation  of  the   Stationary  Distribution  of  an   Infinite  Markov  Matrix 
by   G.    Golub    and  E.    Seneta 

An  algorithm  is  presented  for  computing  the  -unique   stationary 
distribution  of  an   infinite  stochastic  matrix  possessing  at   least   one 
coliimn  whose   elements    are  bounded  away   from  zero.      Elementwise   convergence 
rate   is    discussed  by  means   of  two   examples. 

STAN-CS-73-335  Januaiy  1973 


Calc\iIation  of  GFSR  Pseudorandom  Number  Binary  Starting  Matrix 
by  W.    H.    Payne 

The   generalized  feedback  shift   register  pseudorandom  niimber 
algorithm  produces  the  same  floating-point   sequence  of  pseudorandom  numbers 
on   any   computer.      The   algorithm  requires   a  binary  initialization  matrix. 
A  matrix,    given  both   in  octal   and  hexadecimal,    for  primitive  polynomial, 
modulo   2,    x98  +  x27  +  i   is  listed. 

UIUC-R-73-567  March  1973  1^+  pages  Program  Incl. 


27 


The  SAC-1  Modular  Arithmetic   System 

by  G.    E.    Collins,    L.    E.    Heindel,    E.    Horowitz,   M.    T.   McClellan   and  D.    R.    Musser 

This    is   a  reprinting  of  the  original   report   of  June  I969,  with 
correction  of  a  few  minor  errors.      The  SAC-1  Modular  Arithmetic   System  is 
the  fifth  of  the  ten  SAC-1   subsystems  which  are  now  available.      It  provides 
subprograms    for  the   arithmetic  operations   in  a  prime   finite   field  GF(p), 
for  any  single-precision  prime  p,   and  for  various   operations  on  polynomials 
in  several   variables  with   coefficients   in  GF(p).      Besides  the   arithmetic 
operations  on  such  polynomials  there   are   included  subprograms    for  the 
Chinese  remainder  theorem,    evaluation   and  interpolation.      For  invariate 
polynomials,    subprograms   are  included  for  greatest   common   divisor  calculation 
and  Berlekamp's   factorization  algorithm. 

¥IS-l65  November  1972  50  pages  Program  Incl. 


Gleichungen   in  halbgeordneten  Raumen 
"by  R.    Krawczyk 

Im  ersten  Teil   dieser  Arbeit  wird  eine  Operatorgleichung  Tx  =   9 
in  eine  Operatorgleichung  x  =  Sx  transformiert .      Darauf  werden  Fixpunksatze 
angewendet   und  Fehlerabschatzungen   fiir  eine  Losung  durchgefuhrt .      Das 
allgemeine   Iterationsverfahren  entspricht  bei  variablem  S   dem  WEWTONschen 
Verfahren  in  normierten  Raumen,   ohne   da3      eine  Norm  benotigt  wird.     Anstelle 
der  Frechet-Ableitung  des  Operators   T  tritt   eine  allgemeine  Lips  chit  zbeding\mg 
mit   linearen  Operatoren.      Im  zweiten  Teil  werden   die   abstrakten  SStze   des 
ersten  Teils   auf  einfache  Beispiele:      Gleichungen,    nichtlineare 
Gleichungssysteme,    algebraische  Eigenwertprobleme  angewendet. 

KARL  TO/3  April   1970  16  pages 


Das   Prae-Euler'sche  Limit ierungs verfahren 
by   Karl   Nickel 

Es    sei    {a   }   eine   vollmonoton   fallende  Nullfolge.      Es  wird  ein 
n 
Limit ierungs verfahren   zur  Kbnvergenzverbesserimg  der  alternierenden  Reihe 


I      (-1)   a     angegeben  und  durch   ein  Triplex-ALGOL  60-Programm  realisiert. 


v=o 


Es  werden   apriori-Fehlerschranken   angegeben,    die  Stabilitat  wird  untersucht, 
die  Rundungsfehler  fvor  eine   Klasse   "idealer"  Komputer  werden   abgeschatzt   \md 
es  wird  gezeigt,    dass   das  Verfahren   in   dieser  Klasse   sogar   "n-umerisch 
konvergiert" .      Beispiele   zeigen  die  praktische  Brauchbarkeit    der  Methode. 

KARL  70/7  July  1970  ill  pages  Program  Incl. 


28 


KEY  TO  REPORT  SOURCES 


ANL   -   Argonne  National  Laboratory 
Argonne,  Illinois   60^39 

BTL   -   Bell  Telephone  Laboratories,  Inc. 
Murray  Hill,  New  Jersey   079 71 


CAC 


Center  for  Advanced  Computation 

University  of  Illinois,   Urbana,    Illinois        618OI 


CAL       -       Department   of  Mathematics 

Statistics   and  Computing  Science 
University  of  Calgary,    Calgary 


Alberta,    Canada 


CMU 


CNA 


Carnegie-Mellon  University 
Computer  Science  Department 
Pittsbiorgh,    Pennsylvania        15213 

Center   for  Numerical  Analysis 

University  of  Texas,   Austin,    Texas        78712 


KARL     -        Inst i tut   Fiir  Informatik 
Universitat   Karlsruhe 
Englerstrasse  2,    Postfach      638O 
D  75      Karlsriohe  1,    Germany 


MAC 


MRC 


Massachusetts  Institute  of  Technology 

Project  MAC 

Cambridge,   Massachusetts        02139 

Mathematics  Research  Center 

University  of  Wisconsin,   Madison,    Wisconsin        53706 


PRAK     -        Institut   fur  Praktische  Mathematik 
Universitat   Karlsruhe 
Englerstrasse  2,    Postfach      638O 
D   75      Karlsruhe  1,    Germany 

STAN     -        Computer  Science  Department 

Stanford  University,    Stanford,    California       9^305 


TOR 


Department  of  Computer  Science 
University  of  Toronto,  Ontario,  Canada 


UAE   -   Department  of  Computing  Science 

University  of  Alberta,  Edmonton,  Alberta,  Canada 


UBC 


Department  of  Computer  Science 

University  of  British  Coliombia,  Vancouver,  B.  C,  Canada 


29 


UMINF  - 


UIUC   - 


WIS 


Department  of  Information  Processing 
University  of  Umea,  Umea,  Sweden 

Department  of  Computer  Science 
University  of  Illinois,  Urbana,  Illinois 

Computer  Sciences  Department 
The  University  of  Wisconsin 
1210  West  Dayton  Street 
Madison,  Wisconsin   53T06 


61801 


WSU  -  Computer  Science  Department 
Washington  State  University 
Pullman,  Washington   99l63 

YORK  -   T.  J.  Watson  Research  Center 

Yorktown  Heights,  New  York   IO598 


30 


UNCLASSIFIED 


SECURITY   CL  ASSinCATIOhi   OF    THIS  PAGE   (i*'hrn   Data 

Fnfer^d) 

REPORT  DOCUMENTATION  PAGE 

RliAD  INSTRUCTIONS 
BEFORE  COMPLETING  FORM 

1.     REPORT   NUMQER 

CAC   Document    No,    90 

2.   GOVT    ACCESSION   NO. 

3.      RECIPIENT'S   CATALOG   NUMBER 

4.     TITLE  (end  Subtllle) 

Computational  Mathematics   Abstracts 

5.     TYPE  OF   REPORT  &   PERIOD  COVERED 

Bibliographical  Abstracts 

6.     PERFORMING  ORG.    REPORT  NUMBER 

7.     AUTHORCs; 

Edited  "by:      Geneva   Belford,    Jonathan  Lermit, 
George   Purdy,    and  Ahmed  Sameh 

8.     CONTRACT   OR   GRANT   NUMBER(-»; 
DAHCOJ+-72-C-OOOI 

9.     PERFORMING  ORGANIZATION   NAME   AND  ADDRESS 

Center   for  Advanced  Computation 
University  of  Illinois    at   Urhana-Champaign 
Urhana,    Illinois      618OI 

10.     PROGRAM   ELEMENT.  PROJECT,   TASK 
AREA   4   WORK   UNIT   NUMBERS 

AEPA  Order   No.    l899 

»l.     CONTROLLING  OFFICE   NAME   AND   ADDRESS 

U.S.    Army  Research   Office-Durham 
Duke   Station,    Durham,    North   Carolina 

12.     REPORT   DATE 

October  1973 

13.     NUMBER  OF  PAGES 

32 

U.     MONITORING  AGENCY   NAME  A    ADDRESSf//  dlllerent  from  Controlling  Oflice) 

15.     SECURITY  CLASS,   (oi  thia  report) 

UNCLASSIFIED 

15«.     DECLASSIFICATION/ DOWNGRADING 
SCHEDULE 

16.     DISTRIBUTION   ST  ATEM  EN  T  Co/ <h<s  Repor  (; 

Copies  may  be  requested  from  the  i\[ational  Technical  Information  Service, 
Springfield,  Virginia  22151 


17.     DISTRIBUTION  STATEMENT  (ol  the  abstract  entered  In  Block  20,  II  dlllerent  Irom  Report) 


t8.     SUPPLEMENTARY   NOTES 


19.     KEY  WORDS  (Continue  on  reverse  aide  II  necessary  and  Identlly  by  block  number) 


Numerical  Analysis 
Graph  Theory 
Mathematical  Programming 


20.      ABSTRACT  (Continue  on  reverse   side   II  necessary  and  Idenlily  by  block  number) 


NONE 


DD     1   JAN   73     1473  EDITION  OF    1   NOV  65  IS  OBSOLETE 


UNCLASSIFIED 


SECURITY   CLASSIFICATION  OF   THIS  PAGE  fWTien  Data  Entered) 


m