Contents

• NAME
• SYNOPSIS
  • F95 INTERFACE
  • C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

     zpotrs - solve a system of linear equations A*X = B  with  a
     Hermitian positive definite matrix A using the Cholesky fac-
     torization A = U**H*U or A = L*L**H computed by CPOTRF

SYNOPSIS

     SUBROUTINE ZPOTRS(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

     CHARACTER * 1 UPLO
     DOUBLE COMPLEX A(LDA,*), B(LDB,*)
     INTEGER N, NRHS, LDA, LDB, INFO

     SUBROUTINE ZPOTRS_64(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

     CHARACTER * 1 UPLO
     DOUBLE COMPLEX A(LDA,*), B(LDB,*)
     INTEGER*8 N, NRHS, LDA, LDB, INFO

  F95 INTERFACE
     SUBROUTINE POTRS(UPLO, [N], [NRHS], A, [LDA], B, [LDB], [INFO])

     CHARACTER(LEN=1) :: UPLO
     COMPLEX(8), DIMENSION(:,:) :: A, B
     INTEGER :: N, NRHS, LDA, LDB, INFO

     SUBROUTINE POTRS_64(UPLO, [N], [NRHS], A, [LDA], B, [LDB], [INFO])

     CHARACTER(LEN=1) :: UPLO
     COMPLEX(8), DIMENSION(:,:) :: A, B
     INTEGER(8) :: N, NRHS, LDA, LDB, INFO

  C INTERFACE
     #include <sunperf.h>

     void zpotrs(char uplo, int n, int  nrhs,  doublecomplex  *a,
               int lda, doublecomplex *b, int ldb, int *info);

     void zpotrs_64(char uplo, long n, long  nrhs,  doublecomplex
               *a,  long  lda,  doublecomplex  *b, long ldb, long
               *info);

PURPOSE

     zpotrs solves a system of linear equations A*X =  B  with  a
     Hermitian positive definite matrix A using the Cholesky fac-
     torization A = U**H*U or A = L*L**H computed by CPOTRF.

ARGUMENTS

     UPLO (input)
               = 'U':  Upper triangle of A is stored;
               = 'L':  Lower triangle of A is stored.

     N (input) The order of the matrix A.  N >= 0.

     NRHS (input)
               The number of right hand sides, i.e.,  the  number
               of columns of the matrix B.  NRHS >= 0.

     A (input) The triangular factor U or  L  from  the  Cholesky
               factorization  A  =  U**H*U or A = L*L**H, as com-
               puted by CPOTRF.

     LDA (input)
               The leading dimension of  the  array  A.   LDA  >=
               max(1,N).

     B (input/output)
               On entry, the right hand side matrix B.  On  exit,
               the solution matrix X.

     LDB (input)
               The leading dimension of  the  array  B.   LDB  >=
               max(1,N).

     INFO (output)
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an ille-
               gal value