--- rpl/lapack/blas/dgemv.f 2010/08/07 13:22:08 1.4 +++ rpl/lapack/blas/dgemv.f 2023/08/07 08:38:43 1.17 @@ -1,4 +1,163 @@ +*> \brief \b DGEMV +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +* Definition: +* =========== +* +* SUBROUTINE DGEMV(TRANS,M,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY) +* +* .. Scalar Arguments .. +* DOUBLE PRECISION ALPHA,BETA +* INTEGER INCX,INCY,LDA,M,N +* CHARACTER TRANS +* .. +* .. Array Arguments .. +* DOUBLE PRECISION A(LDA,*),X(*),Y(*) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> DGEMV performs one of the matrix-vector operations +*> +*> y := alpha*A*x + beta*y, or y := alpha*A**T*x + beta*y, +*> +*> where alpha and beta are scalars, x and y are vectors and A is an +*> m by n matrix. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] TRANS +*> \verbatim +*> 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**T*x + beta*y. +*> \endverbatim +*> +*> \param[in] M +*> \verbatim +*> M is INTEGER +*> On entry, M specifies the number of rows of the matrix A. +*> M must be at least zero. +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> On entry, N specifies the number of columns of the matrix A. +*> N must be at least zero. +*> \endverbatim +*> +*> \param[in] ALPHA +*> \verbatim +*> ALPHA is DOUBLE PRECISION. +*> On entry, ALPHA specifies the scalar alpha. +*> \endverbatim +*> +*> \param[in] A +*> \verbatim +*> A is DOUBLE PRECISION array, dimension ( LDA, N ) +*> Before entry, the leading m by n part of the array A must +*> contain the matrix of coefficients. +*> \endverbatim +*> +*> \param[in] LDA +*> \verbatim +*> 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, m ). +*> \endverbatim +*> +*> \param[in] X +*> \verbatim +*> X is DOUBLE PRECISION 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. +*> \endverbatim +*> +*> \param[in] INCX +*> \verbatim +*> INCX is INTEGER +*> On entry, INCX specifies the increment for the elements of +*> X. INCX must not be zero. +*> \endverbatim +*> +*> \param[in] BETA +*> \verbatim +*> BETA is DOUBLE PRECISION. +*> On entry, BETA specifies the scalar beta. When BETA is +*> supplied as zero then Y need not be set on input. +*> \endverbatim +*> +*> \param[in,out] Y +*> \verbatim +*> Y is DOUBLE PRECISION 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 with BETA non-zero, the incremented array Y +*> must contain the vector y. On exit, Y is overwritten by the +*> updated vector y. +*> \endverbatim +*> +*> \param[in] INCY +*> \verbatim +*> INCY is INTEGER +*> On entry, INCY specifies the increment for the elements of +*> Y. INCY must not be zero. +*> \endverbatim +* +* Authors: +* ======== +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \ingroup double_blas_level2 +* +*> \par Further Details: +* ===================== +*> +*> \verbatim +*> +*> 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. +*> \endverbatim +*> +* ===================================================================== SUBROUTINE DGEMV(TRANS,M,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY) +* +* -- Reference BLAS level2 routine -- +* -- Reference BLAS is a software package provided by Univ. of Tennessee, -- +* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- +* * .. Scalar Arguments .. DOUBLE PRECISION ALPHA,BETA INTEGER INCX,INCY,LDA,M,N @@ -8,98 +167,6 @@ DOUBLE PRECISION A(LDA,*),X(*),Y(*) * .. * -* Purpose -* ======= -* -* DGEMV performs one of the matrix-vector operations -* -* y := alpha*A*x + beta*y, or y := alpha*A'*x + beta*y, -* -* where alpha and beta are scalars, x and y are vectors and A is an -* m by n matrix. -* -* Arguments -* ========== -* -* TRANS - 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'*x + beta*y. -* -* TRANS = 'C' or 'c' y := alpha*A'*x + beta*y. -* -* Unchanged on exit. -* -* M - INTEGER. -* On entry, M specifies the number of rows of the matrix A. -* M must be at least zero. -* Unchanged on exit. -* -* N - INTEGER. -* On entry, N specifies the number of columns of the matrix A. -* N must be at least zero. -* Unchanged on exit. -* -* ALPHA - DOUBLE PRECISION. -* On entry, ALPHA specifies the scalar alpha. -* Unchanged on exit. -* -* A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). -* Before entry, the leading m by n part of the array A must -* contain the matrix of coefficients. -* 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, m ). -* Unchanged on exit. -* -* X - DOUBLE PRECISION array of 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. -* Unchanged on exit. -* -* INCX - INTEGER. -* On entry, INCX specifies the increment for the elements of -* X. INCX must not be zero. -* Unchanged on exit. -* -* BETA - DOUBLE PRECISION. -* 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 - DOUBLE PRECISION array of DIMENSION at least -* ( 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 - INTEGER. -* On entry, INCY specifies the increment for the elements of -* Y. INCY must not be zero. -* Unchanged on exit. -* -* Further Details -* =============== -* -* 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. -* * ===================================================================== * * .. Parameters .. @@ -208,30 +275,26 @@ JX = KX IF (INCY.EQ.1) THEN DO 60 J = 1,N - IF (X(JX).NE.ZERO) THEN - TEMP = ALPHA*X(JX) - DO 50 I = 1,M - Y(I) = Y(I) + TEMP*A(I,J) - 50 CONTINUE - END IF + TEMP = ALPHA*X(JX) + DO 50 I = 1,M + Y(I) = Y(I) + TEMP*A(I,J) + 50 CONTINUE JX = JX + INCX 60 CONTINUE ELSE DO 80 J = 1,N - IF (X(JX).NE.ZERO) THEN - TEMP = ALPHA*X(JX) - IY = KY - DO 70 I = 1,M - Y(IY) = Y(IY) + TEMP*A(I,J) - IY = IY + INCY - 70 CONTINUE - END IF + TEMP = ALPHA*X(JX) + IY = KY + DO 70 I = 1,M + Y(IY) = Y(IY) + TEMP*A(I,J) + IY = IY + INCY + 70 CONTINUE JX = JX + INCX 80 CONTINUE END IF ELSE * -* Form y := alpha*A'*x + y. +* Form y := alpha*A**T*x + y. * JY = KY IF (INCX.EQ.1) THEN @@ -259,6 +322,6 @@ * RETURN * -* End of DGEMV . +* End of DGEMV * END