Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages

RedHat 9 (Linux i386) - man page for dtrsv (redhat section l)

DTRSV(l)				   BLAS routine 				 DTRSV(l)

NAME
       DTRSV - solve one of the systems of equations   A*x = b, or A'*x = b,

SYNOPSIS
       SUBROUTINE DTRSV ( UPLO, TRANS, DIAG, N, A, LDA, X, INCX )

	   INTEGER	INCX, LDA, N

	   CHARACTER*1	DIAG, TRANS, UPLO

	   DOUBLE	PRECISION A( LDA, * ), X( * )

PURPOSE
       DTRSV  solves one of the systems of equations

       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.

PARAMETERS
       UPLO   - CHARACTER*1.
	      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.

       TRANS  - CHARACTER*1.
	      On entry, TRANS specifies the equations to be solved as follows:

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

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

	      TRANS = 'C' or 'c'   A'*x = b.

	      Unchanged on exit.

       DIAG   - CHARACTER*1.
	      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      - INTEGER.
	      On entry, N specifies the order of  the  matrix  A.   N  must  be  at  least  zero.
	      Unchanged on exit.

       A      - DOUBLE PRECISION array of DIMENSION ( LDA, n ).
	      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  trian-
	      gular  part of A is not referenced.  Before entry with UPLO = 'L' or 'l', the lead-
	      ing 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    - INTEGER.
	      On  entry,  LDA specifies the first dimension of A as declared in the calling (sub)
	      program. LDA must be at least max( 1, n ).  Unchanged on exit.

       X      - DOUBLE PRECISION array of dimension at least
	      ( 1 + ( n - 1 )*abs( INCX ) ).  Before entry, the incremented array X must  contain
	      the n element right-hand side vector b. On exit, X is overwritten with the solution
	      vector x.

       INCX   - INTEGER.
	      On entry, INCX specifies the increment for the elements of  X.  INCX  must  not  be
	      zero.  Unchanged on exit.

	      Level 2 Blas routine.

	      --  Written  on  22-October-1986.   Jack Dongarra, Argonne National Lab.	Jeremy Du
	      Croz, Nag Central Office.  Sven Hammarling, Nag Central  Office.	 Richard  Hanson,
	      Sandia National Labs.

BLAS routine				 16 October 1992				 DTRSV(l)


All times are GMT -4. The time now is 08:49 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
UNIX.COM Login
Username:
Password:  
Show Password