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dtrsv.f(3) [centos man page]

dtrsv.f(3)							      LAPACK								dtrsv.f(3)

NAME

       dtrsv.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dtrsv (UPLO, TRANS, DIAG, N, A, LDA, X, INCX)
	   DTRSV

Function/Subroutine Documentation
   subroutine dtrsv (characterUPLO, characterTRANS, characterDIAG, integerN, double precision, dimension(lda,*)A, integerLDA, double precision,
       dimension(*)X, integerINCX)
       DTRSV Purpose:

	    DTRSV  solves one of the systems of equations

	       A*x = b,   or   A**T*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.

       Parameters:
	   UPLO

		     UPLO is 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.

	   TRANS

		     TRANS is 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**T*x = b.

			 TRANS = 'C' or 'c'   A**T*x = b.

	   DIAG

		     DIAG is 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.

	   N

		     N is INTEGER
		      On entry, N specifies the order of the matrix A.
		      N must be at least zero.

	   A

		     A is 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 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.

	   LDA

		     LDA is 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 ).

	   X

		     X is 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

		     INCX is INTEGER
		      On entry, INCX specifies the increment for the elements of
		      X. INCX must not be zero.

	     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.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 144 of file dtrsv.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012							dtrsv.f(3)

Check Out this Related Man Page

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 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 refer-
	      enced.  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 Cen-
	      tral Office.  Richard Hanson, Sandia National Labs.

BLAS routine							  16 October 1992							  DTRSV(l)
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