dspgst (3p)

Name

dspgst - definite generalized eigenproblem to standard form, using packed storage

Synopsis

SUBROUTINE DSPGST(ITYPE, UPLO, N, AP, BP, INFO)

CHARACTER*1 UPLO
INTEGER ITYPE, N, INFO
DOUBLE PRECISION AP(*), BP(*)

SUBROUTINE DSPGST_64(ITYPE, UPLO, N, AP, BP, INFO)

CHARACTER*1 UPLO
INTEGER*8 ITYPE, N, INFO
DOUBLE PRECISION AP(*), BP(*)




F95 INTERFACE
SUBROUTINE SPGST(ITYPE, UPLO, N, AP, BP, INFO)

CHARACTER(LEN=1) :: UPLO
INTEGER :: ITYPE, N, INFO
REAL(8), DIMENSION(:) :: AP, BP

SUBROUTINE SPGST_64(ITYPE, UPLO, N, AP, BP, INFO)

CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: ITYPE, N, INFO
REAL(8), DIMENSION(:) :: AP, BP




C INTERFACE
#include <sunperf.h>

void dspgst(int itype, char uplo, int n, double *ap,  double  *bp,  int
*info);

void  dspgst_64(long  itype, char uplo, long n, double *ap, double *bp,
long *info);

Description

Oracle Solaris Studio Performance Library                           dspgst(3P)



NAME
       dspgst  -  reduce a real symmetric-definite generalized eigenproblem to
       standard form, using packed storage


SYNOPSIS
       SUBROUTINE DSPGST(ITYPE, UPLO, N, AP, BP, INFO)

       CHARACTER*1 UPLO
       INTEGER ITYPE, N, INFO
       DOUBLE PRECISION AP(*), BP(*)

       SUBROUTINE DSPGST_64(ITYPE, UPLO, N, AP, BP, INFO)

       CHARACTER*1 UPLO
       INTEGER*8 ITYPE, N, INFO
       DOUBLE PRECISION AP(*), BP(*)




   F95 INTERFACE
       SUBROUTINE SPGST(ITYPE, UPLO, N, AP, BP, INFO)

       CHARACTER(LEN=1) :: UPLO
       INTEGER :: ITYPE, N, INFO
       REAL(8), DIMENSION(:) :: AP, BP

       SUBROUTINE SPGST_64(ITYPE, UPLO, N, AP, BP, INFO)

       CHARACTER(LEN=1) :: UPLO
       INTEGER(8) :: ITYPE, N, INFO
       REAL(8), DIMENSION(:) :: AP, BP




   C INTERFACE
       #include <sunperf.h>

       void dspgst(int itype, char uplo, int n, double *ap,  double  *bp,  int
                 *info);

       void  dspgst_64(long  itype, char uplo, long n, double *ap, double *bp,
                 long *info);



PURPOSE
       dspgst reduces a real symmetric-definite  generalized  eigenproblem  to
       standard form, using packed storage.

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

       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**T or L**T*A*L.

       B must have been previously factorized as U**T*U or L*L**T by DPPTRF.


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


       UPLO (input)
                 =  'U':   Upper  triangle of A is stored and B is factored as
                 U**T*U; = 'L':  Lower triangle of A is stored and B  is  fac-
                 tored as L*L**T.


       N (input) The order of the matrices A and B.  N >= 0.


       AP (input/output)
                 Double  precision  array, dimension (N*(N+1)/2) On entry, the
                 upper or lower triangle of the  symmetric  matrix  A,  packed
                 columnwise in a linear array.  The j-th column of A is stored
                 in the array AP as follows: if UPLO = 'U', AP(i +  (j-1)*j/2)
                 = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) =
                 A(i,j) for j<=i<=n.

                 On exit, if INFO = 0, the transformed matrix, stored  in  the
                 same format as A.


       BP (input)
                 Double  precision array, dimension (N*(N+1)/2) The triangular
                 factor from the Cholesky factorization of B,  stored  in  the
                 same format as A, as returned by DPPTRF.


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




                                  7 Nov 2015                        dspgst(3P)