table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/BLAS/SRC/cgbmv.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/BLAS/SRC/cgbmv.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/BLAS/SRC/cgbmv.f
SYNOPSIS¶
Functions/Subroutines¶
subroutine CGBMV (trans, m, n, kl, ku, alpha, a, lda, x,
incx, beta, y, incy)
CGBMV
Function/Subroutine Documentation¶
subroutine CGBMV (character trans, integer m, integer n, integer kl, integer ku, complex alpha, complex, dimension(lda,*) a, integer lda, complex, dimension(*) x, integer incx, complex beta, complex, dimension(*) y, integer incy)¶
CGBMV
Purpose:
!> !> CGBMV performs one of the matrix-vector operations !> !> y := alpha*A*x + beta*y, or y := alpha*A**T*x + beta*y, or !> !> y := alpha*A**H*x + beta*y, !> !> where alpha and beta are scalars, x and y are vectors and A is an !> m by n band matrix, with kl sub-diagonals and ku super-diagonals. !>
Parameters
TRANS
!> TRANS is CHARACTER*1 !> On entry, TRANS specifies the operation to be performed as !> follows: !> !> TRANS = 'N' or 'n' y := alpha*A*x + beta*y. !> !> TRANS = 'T' or 't' y := alpha*A**T*x + beta*y. !> !> TRANS = 'C' or 'c' y := alpha*A**H*x + beta*y. !>
M
!> M is INTEGER !> On entry, M specifies the number of rows of the matrix A. !> M must be at least zero. !>
N
!> N is INTEGER !> On entry, N specifies the number of columns of the matrix A. !> N must be at least zero. !>
KL
!> KL is INTEGER !> On entry, KL specifies the number of sub-diagonals of the !> matrix A. KL must satisfy 0 .le. KL. !>
KU
!> KU is INTEGER !> On entry, KU specifies the number of super-diagonals of the !> matrix A. KU must satisfy 0 .le. KU. !>
ALPHA
!> ALPHA is COMPLEX !> On entry, ALPHA specifies the scalar alpha. !>
A
!> A is COMPLEX array, dimension ( LDA, N ) !> Before entry, the leading ( kl + ku + 1 ) by n part of the !> array A must contain the matrix of coefficients, supplied !> column by column, with the leading diagonal of the matrix in !> row ( ku + 1 ) of the array, the first super-diagonal !> starting at position 2 in row ku, the first sub-diagonal !> starting at position 1 in row ( ku + 2 ), and so on. !> Elements in the array A that do not correspond to elements !> in the band matrix (such as the top left ku by ku triangle) !> are not referenced. !> The following program segment will transfer a band matrix !> from conventional full matrix storage to band storage: !> !> DO 20, J = 1, N !> K = KU + 1 - J !> DO 10, I = MAX( 1, J - KU ), MIN( M, J + KL ) !> A( K + I, J ) = matrix( I, J ) !> 10 CONTINUE !> 20 CONTINUE !>
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 !> ( kl + ku + 1 ). !>
X
!> X is COMPLEX array, dimension at least !> ( 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. !>
INCX
!> INCX is INTEGER !> On entry, INCX specifies the increment for the elements of !> X. INCX must not be zero. !>
BETA
!> BETA is COMPLEX !> On entry, BETA specifies the scalar beta. When BETA is !> supplied as zero then Y need not be set on input. !>
Y
!> Y is COMPLEX array, dimension at least !> ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' !> and at least !> ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. !> Before entry, the incremented array Y must contain the !> vector y. On exit, Y is overwritten by the updated vector y. !> If either m or n is zero, then Y not referenced and the function !> performs a quick return. !>
INCY
!> INCY is INTEGER !> On entry, INCY specifies the increment for the elements of !> Y. INCY must not be zero. !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
!> !> Level 2 Blas routine. !> The vector and matrix arguments are not referenced when N = 0, or M = 0 !> !> -- 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. !>
Definition at line 188 of file cgbmv.f.
Author¶
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