dposv (3p)

Name

dposv - compute the solution to a real system of linear equations A*X = B, where A is an N-by-N symmetric positive definite matrix and X and B are N-by-NRHS matrices

Synopsis

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

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

SUBROUTINE DPOSV_64(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

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




F95 INTERFACE
SUBROUTINE POSV(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

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

SUBROUTINE POSV_64(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

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




C INTERFACE
#include <sunperf.h>

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

void dposv_64(char uplo, long n, long nrhs, double *a, long lda, double
*b, long ldb, long *info);

Description

Oracle Solaris Studio Performance Library                            dposv(3P)



NAME
       dposv  - compute the solution to a real system of linear equations  A*X
       = B, where A is an N-by-N symmetric positive definite matrix and X  and
       B are N-by-NRHS matrices


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

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

       SUBROUTINE DPOSV_64(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

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




   F95 INTERFACE
       SUBROUTINE POSV(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

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

       SUBROUTINE POSV_64(UPLO, N, NRHS, A, LDA, B, LDB, INFO)

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




   C INTERFACE
       #include <sunperf.h>

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

       void dposv_64(char uplo, long n, long nrhs, double *a, long lda, double
                 *b, long ldb, long *info);



PURPOSE
       dposv computes the solution to a real system of linear equations
          A  *  X = B, where A is an N-by-N symmetric positive definite matrix
       and X and B are N-by-NRHS matrices.

       The Cholesky decomposition is used to factor A as
          A = U**T* U,  if UPLO = 'U', or
          A = L * L**T,  if UPLO = 'L',
       where U is an upper triangular matrix  and  L  is  a  lower  triangular
       matrix.   The  factored  form  of A is then used to solve the system of
       equations A * X = B.


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


       N (input) The number of linear equations, i.e., 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/output)
                 On entry, the symmetric matrix A.  If UPLO = 'U', the leading
                 N-by-N upper triangular part of A contains the upper triangu-
                 lar part of the matrix A, and the strictly  lower  triangular
                 part  of  A is not referenced.  If UPLO = 'L', the leading N-
                 by-N lower triangular part of A contains the lower triangular
                 part  of the matrix A, and the strictly upper triangular part
                 of A is not referenced.

                 On exit, if INFO = 0, the factor U or  L  from  the  Cholesky
                 factorization A = U**T*U or A = L*L**T.


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


       B (input/output)
                 On  entry,  the N-by-NRHS right hand side matrix B.  On exit,
                 if INFO = 0, the N-by-NRHS 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 illegal value
                 > 0:  if INFO = i, the leading minor of order i of A  is  not
                 positive  definite,  so  the  factorization could not be com-
                 pleted, and the solution has not been computed.




                                  7 Nov 2015                         dposv(3P)