forked from lijiext/lammps
228 lines
5.6 KiB
Fortran
228 lines
5.6 KiB
Fortran
*> \brief \b DGER
|
|
*
|
|
* =========== DOCUMENTATION ===========
|
|
*
|
|
* Online html documentation available at
|
|
* http://www.netlib.org/lapack/explore-html/
|
|
*
|
|
* Definition:
|
|
* ===========
|
|
*
|
|
* SUBROUTINE DGER(M,N,ALPHA,X,INCX,Y,INCY,A,LDA)
|
|
*
|
|
* .. Scalar Arguments ..
|
|
* DOUBLE PRECISION ALPHA
|
|
* INTEGER INCX,INCY,LDA,M,N
|
|
* ..
|
|
* .. Array Arguments ..
|
|
* DOUBLE PRECISION A(LDA,*),X(*),Y(*)
|
|
* ..
|
|
*
|
|
*
|
|
*> \par Purpose:
|
|
* =============
|
|
*>
|
|
*> \verbatim
|
|
*>
|
|
*> DGER performs the rank 1 operation
|
|
*>
|
|
*> A := alpha*x*y**T + A,
|
|
*>
|
|
*> where alpha is a scalar, x is an m element vector, y is an n element
|
|
*> vector and A is an m by n matrix.
|
|
*> \endverbatim
|
|
*
|
|
* Arguments:
|
|
* ==========
|
|
*
|
|
*> \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] X
|
|
*> \verbatim
|
|
*> X is DOUBLE PRECISION array of dimension at least
|
|
*> ( 1 + ( m - 1 )*abs( INCX ) ).
|
|
*> Before entry, the incremented array X must contain the m
|
|
*> element 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] Y
|
|
*> \verbatim
|
|
*> Y is DOUBLE PRECISION array of dimension at least
|
|
*> ( 1 + ( n - 1 )*abs( INCY ) ).
|
|
*> Before entry, the incremented array Y must contain the n
|
|
*> element 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
|
|
*>
|
|
*> \param[in,out] A
|
|
*> \verbatim
|
|
*> A is 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. On exit, A is
|
|
*> overwritten by the updated matrix.
|
|
*> \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
|
|
*
|
|
* Authors:
|
|
* ========
|
|
*
|
|
*> \author Univ. of Tennessee
|
|
*> \author Univ. of California Berkeley
|
|
*> \author Univ. of Colorado Denver
|
|
*> \author NAG Ltd.
|
|
*
|
|
*> \date November 2011
|
|
*
|
|
*> \ingroup double_blas_level2
|
|
*
|
|
*> \par Further Details:
|
|
* =====================
|
|
*>
|
|
*> \verbatim
|
|
*>
|
|
*> 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.
|
|
*> \endverbatim
|
|
*>
|
|
* =====================================================================
|
|
SUBROUTINE DGER(M,N,ALPHA,X,INCX,Y,INCY,A,LDA)
|
|
*
|
|
* -- Reference BLAS level2 routine (version 3.4.0) --
|
|
* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
|
|
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
|
* November 2011
|
|
*
|
|
* .. Scalar Arguments ..
|
|
DOUBLE PRECISION ALPHA
|
|
INTEGER INCX,INCY,LDA,M,N
|
|
* ..
|
|
* .. Array Arguments ..
|
|
DOUBLE PRECISION A(LDA,*),X(*),Y(*)
|
|
* ..
|
|
*
|
|
* =====================================================================
|
|
*
|
|
* .. Parameters ..
|
|
DOUBLE PRECISION ZERO
|
|
PARAMETER (ZERO=0.0D+0)
|
|
* ..
|
|
* .. Local Scalars ..
|
|
DOUBLE PRECISION TEMP
|
|
INTEGER I,INFO,IX,J,JY,KX
|
|
* ..
|
|
* .. External Subroutines ..
|
|
EXTERNAL XERBLA
|
|
* ..
|
|
* .. Intrinsic Functions ..
|
|
INTRINSIC MAX
|
|
* ..
|
|
*
|
|
* Test the input parameters.
|
|
*
|
|
INFO = 0
|
|
IF (M.LT.0) THEN
|
|
INFO = 1
|
|
ELSE IF (N.LT.0) THEN
|
|
INFO = 2
|
|
ELSE IF (INCX.EQ.0) THEN
|
|
INFO = 5
|
|
ELSE IF (INCY.EQ.0) THEN
|
|
INFO = 7
|
|
ELSE IF (LDA.LT.MAX(1,M)) THEN
|
|
INFO = 9
|
|
END IF
|
|
IF (INFO.NE.0) THEN
|
|
CALL XERBLA('DGER ',INFO)
|
|
RETURN
|
|
END IF
|
|
*
|
|
* Quick return if possible.
|
|
*
|
|
IF ((M.EQ.0) .OR. (N.EQ.0) .OR. (ALPHA.EQ.ZERO)) RETURN
|
|
*
|
|
* Start the operations. In this version the elements of A are
|
|
* accessed sequentially with one pass through A.
|
|
*
|
|
IF (INCY.GT.0) THEN
|
|
JY = 1
|
|
ELSE
|
|
JY = 1 - (N-1)*INCY
|
|
END IF
|
|
IF (INCX.EQ.1) THEN
|
|
DO 20 J = 1,N
|
|
IF (Y(JY).NE.ZERO) THEN
|
|
TEMP = ALPHA*Y(JY)
|
|
DO 10 I = 1,M
|
|
A(I,J) = A(I,J) + X(I)*TEMP
|
|
10 CONTINUE
|
|
END IF
|
|
JY = JY + INCY
|
|
20 CONTINUE
|
|
ELSE
|
|
IF (INCX.GT.0) THEN
|
|
KX = 1
|
|
ELSE
|
|
KX = 1 - (M-1)*INCX
|
|
END IF
|
|
DO 40 J = 1,N
|
|
IF (Y(JY).NE.ZERO) THEN
|
|
TEMP = ALPHA*Y(JY)
|
|
IX = KX
|
|
DO 30 I = 1,M
|
|
A(I,J) = A(I,J) + X(IX)*TEMP
|
|
IX = IX + INCX
|
|
30 CONTINUE
|
|
END IF
|
|
JY = JY + INCY
|
|
40 CONTINUE
|
|
END IF
|
|
*
|
|
RETURN
|
|
*
|
|
* End of DGER .
|
|
*
|
|
END
|