cpttrs (3p)

Name

cpttrs - solve a tridiagonal system of the form A * X = B using the factorization A = U'*D*U or A = L*D*L' computed by CPTTRF

Synopsis

SUBROUTINE CPTTRS(UPLO, N, NRHS, D, E, B, LDB, INFO)

CHARACTER*1 UPLO
COMPLEX E(*), B(LDB,*)
INTEGER N, NRHS, LDB, INFO
REAL D(*)

SUBROUTINE CPTTRS_64(UPLO, N, NRHS, D, E, B, LDB, INFO)

CHARACTER*1 UPLO
COMPLEX E(*), B(LDB,*)
INTEGER*8 N, NRHS, LDB, INFO
REAL D(*)




F95 INTERFACE
SUBROUTINE PTTRS(UPLO, N, NRHS, D, E, B, LDB, INFO)

CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: E
COMPLEX, DIMENSION(:,:) :: B
INTEGER :: N, NRHS, LDB, INFO
REAL, DIMENSION(:) :: D

SUBROUTINE PTTRS_64(UPLO, N, NRHS, D, E, B, LDB, INFO)

CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: E
COMPLEX, DIMENSION(:,:) :: B
INTEGER(8) :: N, NRHS, LDB, INFO
REAL, DIMENSION(:) :: D




C INTERFACE
#include <sunperf.h>

void cpttrs(char uplo, int n, int nrhs, float *d, complex  *e,  complex
*b, int ldb, int *info);

void cpttrs_64(char uplo, long n, long nrhs, float *d, complex *e, com-
plex *b, long ldb, long *info);

Description

Oracle Solaris Studio Performance Library                           cpttrs(3P)



NAME
       cpttrs  -  solve  a tridiagonal system of the form  A * X = B using the
       factorization A = U'*D*U or A = L*D*L' computed by CPTTRF


SYNOPSIS
       SUBROUTINE CPTTRS(UPLO, N, NRHS, D, E, B, LDB, INFO)

       CHARACTER*1 UPLO
       COMPLEX E(*), B(LDB,*)
       INTEGER N, NRHS, LDB, INFO
       REAL D(*)

       SUBROUTINE CPTTRS_64(UPLO, N, NRHS, D, E, B, LDB, INFO)

       CHARACTER*1 UPLO
       COMPLEX E(*), B(LDB,*)
       INTEGER*8 N, NRHS, LDB, INFO
       REAL D(*)




   F95 INTERFACE
       SUBROUTINE PTTRS(UPLO, N, NRHS, D, E, B, LDB, INFO)

       CHARACTER(LEN=1) :: UPLO
       COMPLEX, DIMENSION(:) :: E
       COMPLEX, DIMENSION(:,:) :: B
       INTEGER :: N, NRHS, LDB, INFO
       REAL, DIMENSION(:) :: D

       SUBROUTINE PTTRS_64(UPLO, N, NRHS, D, E, B, LDB, INFO)

       CHARACTER(LEN=1) :: UPLO
       COMPLEX, DIMENSION(:) :: E
       COMPLEX, DIMENSION(:,:) :: B
       INTEGER(8) :: N, NRHS, LDB, INFO
       REAL, DIMENSION(:) :: D




   C INTERFACE
       #include <sunperf.h>

       void cpttrs(char uplo, int n, int nrhs, float *d, complex  *e,  complex
                 *b, int ldb, int *info);

       void cpttrs_64(char uplo, long n, long nrhs, float *d, complex *e, com-
                 plex *b, long ldb, long *info);



PURPOSE
       cpttrs solves a tridiagonal system of the form
          A * X = B using the factorization A = U'*D*U or A = L*D*L'  computed
       by  CPTTRF.  D is a diagonal matrix specified in the vector D, U (or L)
       is a unit bidiagonal matrix whose superdiagonal (subdiagonal) is speci-
       fied in the vector E, and X and B are N by NRHS matrices.


ARGUMENTS
       UPLO (input)
                 Specifies  the form of the factorization and whether the vec-
                 tor E is the superdiagonal of the upper bidiagonal  factor  U
                 or  the subdiagonal of the lower bidiagonal factor L.  = 'U':
                 A = U'*D*U, E is the superdiagonal of U
                 = 'L':  A = L*D*L', E is the subdiagonal of L


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


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


       D (input) The  n  diagonal  elements  of the diagonal matrix D from the
                 factorization A = U'*D*U or A = L*D*L'.


       E (input) If UPLO = 'U', the (n-1) superdiagonal elements of  the  unit
                 bidiagonal  factor  U  from the factorization A = U'*D*U.  If
                 UPLO = 'L', the (n-1) subdiagonal elements of the unit  bidi-
                 agonal factor L from the factorization A = L*D*L'.


       B (input/output)
                 On  entry,  the  right  hand side vectors B for the system of
                 linear equations.  On exit, the solution vectors, X.


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


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




                                  7 Nov 2015                        cpttrs(3P)