ztrsv

NAME

ztrsv - solve one of the systems of equations A*x = b, or A'*x = b, or conjg( A' )*x = b

SYNOPSIS 

  SUBROUTINE ZTRSV( UPLO, TRANSA, DIAG, N, A, LDA, Y, INCY)
  CHARACTER * 1 UPLO, TRANSA, DIAG
  DOUBLE COMPLEX A(LDA,*), Y(*)
  INTEGER N, LDA, INCY
 
  SUBROUTINE ZTRSV_64( UPLO, TRANSA, DIAG, N, A, LDA, Y, INCY)
  CHARACTER * 1 UPLO, TRANSA, DIAG
  DOUBLE COMPLEX A(LDA,*), Y(*)
  INTEGER*8 N, LDA, INCY

F95 INTERFACE 

  SUBROUTINE TRSV( UPLO, [TRANSA], DIAG, [N], A, [LDA], Y, [INCY])
  CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
  COMPLEX(8), DIMENSION(:) :: Y
  COMPLEX(8), DIMENSION(:,:) :: A
  INTEGER :: N, LDA, INCY
 
  SUBROUTINE TRSV_64( UPLO, [TRANSA], DIAG, [N], A, [LDA], Y, [INCY])
  CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
  COMPLEX(8), DIMENSION(:) :: Y
  COMPLEX(8), DIMENSION(:,:) :: A
  INTEGER(8) :: N, LDA, INCY

C INTERFACE

#include <sunperf.h>

void ztrsv(char uplo, char transa, char diag, int n, doublecomplex *a, int lda, doublecomplex *y, int incy);

void ztrsv_64(char uplo, char transa, char diag, long n, doublecomplex *a, long lda, doublecomplex *y, long incy);

PURPOSE

ztrsv solves one of the systems of equations A*x = b, or A'*x = b, or conjg( A' )*x = b where b and x are n element vectors and A is an n by n unit, or non-unit, upper or lower triangular matrix.

No test for singularity or near-singularity is included in this routine. Such tests must be performed before calling this routine.

ARGUMENTS

* UPLO (input)
On entry, UPLO specifies whether the matrix is an upper or lower triangular matrix as follows:

UPLO = 'U' or 'u' A is an upper triangular matrix.

UPLO = 'L' or 'l' A is a lower triangular matrix.

Unchanged on exit.

* TRANSA (input)
On entry, TRANSA specifies the equations to be solved as follows:

TRANSA = 'N' or 'n' A*x = b.

TRANSA = 'T' or 't' A'*x = b.

TRANSA = 'C' or 'c' conjg( A' )*x = b.

Unchanged on exit.

* DIAG (input)
On entry, DIAG specifies whether or not A is unit triangular as follows:

DIAG = 'U' or 'u' A is assumed to be unit triangular.

DIAG = 'N' or 'n' A is not assumed to be unit triangular.

Unchanged on exit.

* N (input)
On entry, N specifies the order of the matrix A. N >= 0. Unchanged on exit.

* A (input)
Before entry with UPLO = 'U' or 'u', the leading n by n upper triangular part of the array A must contain the upper triangular matrix and the strictly lower triangular part of A is not referenced. Before entry with UPLO = 'L' or 'l', the leading n by n lower triangular part of the array A must contain the lower triangular matrix and the strictly upper triangular part of A is not referenced. Note that when DIAG = 'U' or 'u', the diagonal elements of A are not referenced either, but are assumed to be unity. Unchanged on exit.

* LDA (input)
On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA >= max( 1, n ). Unchanged on exit.

* Y (input/output)
( 1 + ( n - 1 )*abs( INCY ) ). Before entry, the incremented array Y must contain the n element right-hand side vector b. On exit, Y is overwritten with the solution vector x.

* INCY (input)
On entry, INCY specifies the increment for the elements of Y. INCY <> 0. Unchanged on exit.