Unix/Linux Go Back    


CentOS 7.0 - man page for cla_gbamv.f (centos section 3)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


cla_gbamv.f(3)				      LAPACK				   cla_gbamv.f(3)

NAME
       cla_gbamv.f -

SYNOPSIS
   Functions/Subroutines
       subroutine cla_gbamv (TRANS, M, N, KL, KU, ALPHA, AB, LDAB, X, INCX, BETA, Y, INCY)
	   CLA_GBAMV performs a matrix-vector operation to calculate error bounds.

Function/Subroutine Documentation
   subroutine cla_gbamv (integerTRANS, integerM, integerN, integerKL, integerKU, realALPHA,
       complex, dimension( ldab, * )AB, integerLDAB, complex, dimension( * )X, integerINCX,
       realBETA, real, dimension( * )Y, integerINCY)
       CLA_GBAMV performs a matrix-vector operation to calculate error bounds.

       Purpose:

	    CLA_GBAMV  performs one of the matrix-vector operations

		    y := alpha*abs(A)*abs(x) + beta*abs(y),
	       or   y := alpha*abs(A)**T*abs(x) + beta*abs(y),

	    where alpha and beta are scalars, x and y are vectors and A is an
	    m by n matrix.

	    This function is primarily used in calculating error bounds.
	    To protect against underflow during evaluation, components in
	    the resulting vector are perturbed away from zero by (N+1)
	    times the underflow threshold.  To prevent unnecessarily large
	    errors for block-structure embedded in general matrices,
	    "symbolically" zero components are not perturbed.  A zero
	    entry is considered "symbolic" if all multiplications involved
	    in computing that entry have at least one zero multiplicand.

       Parameters:
	   TRANS

		     TRANS is INTEGER
		      On entry, TRANS specifies the operation to be performed as
		      follows:

			BLAS_NO_TRANS	   y := alpha*abs(A)*abs(x) + beta*abs(y)
			BLAS_TRANS	   y := alpha*abs(A**T)*abs(x) + beta*abs(y)
			BLAS_CONJ_TRANS    y := alpha*abs(A**T)*abs(x) + beta*abs(y)

		      Unchanged on exit.

	   M

		     M is INTEGER
		      On entry, M specifies the number of rows of the matrix A.
		      M must be at least zero.
		      Unchanged on exit.

	   N

		     N is INTEGER
		      On entry, N specifies the number of columns of the matrix A.
		      N must be at least zero.
		      Unchanged on exit.

	   KL

		     KL is INTEGER
		      The number of subdiagonals within the band of A.	KL >= 0.

	   KU

		     KU is INTEGER
		      The number of superdiagonals within the band of A.  KU >= 0.

	   ALPHA

		     ALPHA is REAL
		      On entry, ALPHA specifies the scalar alpha.
		      Unchanged on exit.

	   AB

		     AB is REAL array, dimension (LDAB,n)
		      Before entry, the leading m by n part of the array AB must
		      contain the matrix of coefficients.
		      Unchanged on exit.

	   LDAB

		     LDAB is INTEGER
		      On entry, LDAB specifies the first dimension of AB as declared
		      in the calling (sub) program. LDAB must be at least
		      max( 1, m ).
		      Unchanged on exit.

	   X

		     X is REAL array, dimension
		      ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n'
		      and at least
		      ( 1 + ( m - 1 )*abs( INCX ) ) otherwise.
		      Before entry, the incremented array X must contain the
		      vector x.
		      Unchanged on exit.

	   INCX

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

	   BETA

		     BETA is REAL
		      On entry, BETA specifies the scalar beta. When BETA is
		      supplied as zero then Y need not be set on input.
		      Unchanged on exit.

	   Y

		     Y is REAL array, dimension
		      ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n'
		      and at least
		      ( 1 + ( n - 1 )*abs( INCY ) ) otherwise.
		      Before entry with BETA non-zero, the incremented array Y
		      must contain the vector y. On exit, Y is overwritten by the
		      updated vector y.

	   INCY

		     INCY is INTEGER
		      On entry, INCY specifies the increment for the elements of
		      Y. INCY must not be zero.
		      Unchanged on exit.

	     Level 2 Blas routine.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Definition at line 186 of file cla_gbamv.f.

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

Version 3.4.2				 Tue Sep 25 2012			   cla_gbamv.f(3)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 09:05 PM.