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Updated: June 2017
 
 

zgttrs (3p)

Name

zgttrs - solve one of the systems of equations A*X=B, A**T*X=B, or A**H *X=B, with a tridiagonal matrix A using the LU factorization computed by ZGTTRF

Synopsis

SUBROUTINE ZGTTRS(TRANSA, N, NRHS, LOW, D, UP1, UP2, IPIVOT, B,
LDB, INFO)

CHARACTER*1 TRANSA
DOUBLE COMPLEX LOW(*), D(*), UP1(*), UP2(*), B(LDB,*)
INTEGER N, NRHS, LDB, INFO
INTEGER IPIVOT(*)

SUBROUTINE ZGTTRS_64(TRANSA, N, NRHS, LOW, D, UP1, UP2, IPIVOT, B,
LDB, INFO)

CHARACTER*1 TRANSA
DOUBLE COMPLEX LOW(*), D(*), UP1(*), UP2(*), B(LDB,*)
INTEGER*8 N, NRHS, LDB, INFO
INTEGER*8 IPIVOT(*)




F95 INTERFACE
SUBROUTINE GTTRS(TRANSA, N, NRHS, LOW, D, UP1, UP2, IPIVOT,
B, LDB, INFO)

CHARACTER(LEN=1) :: TRANSA
COMPLEX(8), DIMENSION(:) :: LOW, D, UP1, UP2
COMPLEX(8), DIMENSION(:,:) :: B
INTEGER :: N, NRHS, LDB, INFO
INTEGER, DIMENSION(:) :: IPIVOT

SUBROUTINE GTTRS_64(TRANSA, N, NRHS, LOW, D, UP1, UP2,
IPIVOT, B, LDB, INFO)

CHARACTER(LEN=1) :: TRANSA
COMPLEX(8), DIMENSION(:) :: LOW, D, UP1, UP2
COMPLEX(8), DIMENSION(:,:) :: B
INTEGER(8) :: N, NRHS, LDB, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT




C INTERFACE
#include <sunperf.h>

void  zgttrs(char  transa, int n, int nrhs, doublecomplex *low, double-
complex  *d,  doublecomplex  *up1,  doublecomplex  *up2,  int
*ipivot, doublecomplex *b, int ldb, int *info);

void zgttrs_64(char transa, long n, long nrhs, doublecomplex *low, dou-
blecomplex *d, doublecomplex *up1, doublecomplex  *up2,  long
*ipivot, doublecomplex *b, long ldb, long *info);

Description

Oracle Solaris Studio Performance Library                           zgttrs(3P)



NAME
       zgttrs - solve one of the systems of equations A*X=B, A**T*X=B, or A**H
       *X=B, with a tridiagonal matrix A using the LU  factorization  computed
       by ZGTTRF


SYNOPSIS
       SUBROUTINE ZGTTRS(TRANSA, N, NRHS, LOW, D, UP1, UP2, IPIVOT, B,
             LDB, INFO)

       CHARACTER*1 TRANSA
       DOUBLE COMPLEX LOW(*), D(*), UP1(*), UP2(*), B(LDB,*)
       INTEGER N, NRHS, LDB, INFO
       INTEGER IPIVOT(*)

       SUBROUTINE ZGTTRS_64(TRANSA, N, NRHS, LOW, D, UP1, UP2, IPIVOT, B,
             LDB, INFO)

       CHARACTER*1 TRANSA
       DOUBLE COMPLEX LOW(*), D(*), UP1(*), UP2(*), B(LDB,*)
       INTEGER*8 N, NRHS, LDB, INFO
       INTEGER*8 IPIVOT(*)




   F95 INTERFACE
       SUBROUTINE GTTRS(TRANSA, N, NRHS, LOW, D, UP1, UP2, IPIVOT,
              B, LDB, INFO)

       CHARACTER(LEN=1) :: TRANSA
       COMPLEX(8), DIMENSION(:) :: LOW, D, UP1, UP2
       COMPLEX(8), DIMENSION(:,:) :: B
       INTEGER :: N, NRHS, LDB, INFO
       INTEGER, DIMENSION(:) :: IPIVOT

       SUBROUTINE GTTRS_64(TRANSA, N, NRHS, LOW, D, UP1, UP2,
              IPIVOT, B, LDB, INFO)

       CHARACTER(LEN=1) :: TRANSA
       COMPLEX(8), DIMENSION(:) :: LOW, D, UP1, UP2
       COMPLEX(8), DIMENSION(:,:) :: B
       INTEGER(8) :: N, NRHS, LDB, INFO
       INTEGER(8), DIMENSION(:) :: IPIVOT




   C INTERFACE
       #include <sunperf.h>

       void  zgttrs(char  transa, int n, int nrhs, doublecomplex *low, double-
                 complex  *d,  doublecomplex  *up1,  doublecomplex  *up2,  int
                 *ipivot, doublecomplex *b, int ldb, int *info);

       void zgttrs_64(char transa, long n, long nrhs, doublecomplex *low, dou-
                 blecomplex *d, doublecomplex *up1, doublecomplex  *up2,  long
                 *ipivot, doublecomplex *b, long ldb, long *info);



PURPOSE
       zgttrs solves one of the systems of equations
          A  *  X  =  B,   A**T * X = B,  or  A**H * X = B, with a tridiagonal
       matrix A using the LU factorization computed by ZGTTRF.


ARGUMENTS
       TRANSA (input)
                 Specifies the form of the system of equations.  = 'N':  A * X
                 = B     (No transpose)
                 = 'T':  A**T * X = B  (Transpose)
                 = 'C':  A**H * X = B  (Conjugate transpose)


       N (input) The order of the matrix A.


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


       LOW (input)
                 The (n-1) multipliers that define the matrix L  from  the  LU
                 factorization of A.


       D (input) The n diagonal elements of the upper triangular matrix U from
                 the LU factorization of A.


       UP1 (input)
                 The (n-1) elements of the first super-diagonal of U.


       UP2 (input)
                 The (n-2) elements of the second super-diagonal of U.


       IPIVOT (input)
                 The pivot indices; for 1 <= i <= n, row i of the  matrix  was
                 interchanged  with  row  IPIVOT(i).  IPIVOT(i) will always be
                 either i or i+1; IPIVOT(i) = i indicates  a  row  interchange
                 was not required.


       B (input/output)
                 On  entry, the matrix of right hand side vectors B.  On exit,
                 B is overwritten by 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                        zgttrs(3P)