ssygs2 (3p)

Name

ssygs2 - definite generalized eigenproblem to standard form

Synopsis

SUBROUTINE SSYGS2(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

CHARACTER*1 UPLO
INTEGER ITYPE, N, LDA, LDB, INFO
REAL A(LDA,*), B(LDB,*)

SUBROUTINE SSYGS2_64(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

CHARACTER*1 UPLO
INTEGER*8 ITYPE, N, LDA, LDB, INFO
REAL A(LDA,*), B(LDB,*)




F95 INTERFACE
SUBROUTINE SYGS2(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

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

SUBROUTINE SYGS2_64(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

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




C INTERFACE
#include <sunperf.h>

void ssygs2(int itype, char uplo, int n, float *a, int lda,  float  *b,
int ldb, int *info);

void ssygs2_64(long itype, char uplo, long n, float *a, long lda, float
*b, long ldb, long *info);

Description

Oracle Solaris Studio Performance Library                           ssygs2(3P)



NAME
       ssygs2  -  reduce a real symmetric-definite generalized eigenproblem to
       standard form


SYNOPSIS
       SUBROUTINE SSYGS2(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

       CHARACTER*1 UPLO
       INTEGER ITYPE, N, LDA, LDB, INFO
       REAL A(LDA,*), B(LDB,*)

       SUBROUTINE SSYGS2_64(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

       CHARACTER*1 UPLO
       INTEGER*8 ITYPE, N, LDA, LDB, INFO
       REAL A(LDA,*), B(LDB,*)




   F95 INTERFACE
       SUBROUTINE SYGS2(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

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

       SUBROUTINE SYGS2_64(ITYPE, UPLO, N, A, LDA, B, LDB, INFO)

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




   C INTERFACE
       #include <sunperf.h>

       void ssygs2(int itype, char uplo, int n, float *a, int lda,  float  *b,
                 int ldb, int *info);

       void ssygs2_64(long itype, char uplo, long n, float *a, long lda, float
                 *b, long ldb, long *info);



PURPOSE
       ssygs2 reduces a real symmetric-definite  generalized  eigenproblem  to
       standard form.

       If ITYPE = 1, the problem is A*x = lambda*B*x,
       and A is overwritten by inv(U')*A*inv(U) or inv(L)*A*inv(L')

       If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or
       B*A*x = lambda*x, and A is overwritten by U*A*U` or L'*A*L.

       B must have been previously factorized as U'*U or L*L' by SPOTRF.


ARGUMENTS
       ITYPE (input)
                 = 1: compute inv(U')*A*inv(U) or inv(L)*A*inv(L');
                 = 2 or 3: compute U*A*U' or L'*A*L.


       UPLO (input)
                 Specifies  whether  the upper or lower triangular part of the
                 symmetric matrix A is stored, and how B has been  factorized.
                 = 'U':  Upper triangular
                 = 'L':  Lower triangular


       N (input) The order of the matrices A and B.  N >= 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 transformed matrix, stored in the
                 same format as A.


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


       B (input) The triangular factor from the Cholesky factorization  of  B,
                 as returned by SPOTRF.


       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.




                                  7 Nov 2015                        ssygs2(3P)