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Diffstat (limited to '2.3-1/src/fortran/blas/dger.f')
| -rw-r--r-- | 2.3-1/src/fortran/blas/dger.f | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/2.3-1/src/fortran/blas/dger.f b/2.3-1/src/fortran/blas/dger.f new file mode 100644 index 00000000..d316000a --- /dev/null +++ b/2.3-1/src/fortran/blas/dger.f @@ -0,0 +1,157 @@ + 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( * ) +* .. +* +* Purpose +* ======= +* +* DGER performs the rank 1 operation +* +* A := alpha*x*y' + 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. +* +* Parameters +* ========== +* +* 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. +* +* X - 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. +* Unchanged on exit. +* +* INCX - INTEGER. +* On entry, INCX specifies the increment for the elements of +* X. INCX must not be zero. +* Unchanged on exit. +* +* Y - 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. +* Unchanged on exit. +* +* INCY - INTEGER. +* On entry, INCY specifies the increment for the elements of +* Y. INCY must not be zero. +* 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. On exit, A is +* overwritten by the updated matrix. +* +* 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. +* +* +* 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 .. + 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 +* .. +* .. Executable Statements .. +* +* 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 |