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165 lines
4.3 KiB
165 lines
4.3 KiB
#include "clapack.h" |
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/* Subroutine */ int dger_(integer *_m, integer *_n, doublereal *_alpha, |
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doublereal *x, integer *_incx, doublereal *y, integer *_incy, |
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doublereal *a, integer *_lda) |
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{ |
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/* .. Scalar Arguments .. */ |
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/* .. */ |
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/* .. Array Arguments .. */ |
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/* .. */ |
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/* Purpose */ |
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/* ======= */ |
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/* DGER performs the rank 1 operation */ |
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/* A := alpha*x*y' + A, */ |
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/* where alpha is a scalar, x is an m element vector, y is an n element */ |
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/* vector and A is an m by n matrix. */ |
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/* Arguments */ |
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/* ========== */ |
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/* M - INTEGER. */ |
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/* On entry, M specifies the number of rows of the matrix A. */ |
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/* M must be at least zero. */ |
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/* Unchanged on exit. */ |
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/* N - INTEGER. */ |
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/* On entry, N specifies the number of columns of the matrix A. */ |
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/* N must be at least zero. */ |
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/* Unchanged on exit. */ |
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/* ALPHA - DOUBLE PRECISION. */ |
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/* On entry, ALPHA specifies the scalar alpha. */ |
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/* Unchanged on exit. */ |
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/* X - DOUBLE PRECISION array of dimension at least */ |
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/* ( 1 + ( m - 1 )*abs( INCX ) ). */ |
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/* Before entry, the incremented array X must contain the m */ |
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/* element vector x. */ |
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/* Unchanged on exit. */ |
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/* INCX - INTEGER. */ |
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/* On entry, INCX specifies the increment for the elements of */ |
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/* X. INCX must not be zero. */ |
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/* Unchanged on exit. */ |
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/* Y - DOUBLE PRECISION array of dimension at least */ |
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/* ( 1 + ( n - 1 )*abs( INCY ) ). */ |
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/* Before entry, the incremented array Y must contain the n */ |
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/* element vector y. */ |
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/* Unchanged on exit. */ |
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/* INCY - INTEGER. */ |
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/* On entry, INCY specifies the increment for the elements of */ |
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/* Y. INCY must not be zero. */ |
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/* Unchanged on exit. */ |
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/* A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). */ |
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/* Before entry, the leading m by n part of the array A must */ |
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/* contain the matrix of coefficients. On exit, A is */ |
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/* overwritten by the updated matrix. */ |
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/* LDA - INTEGER. */ |
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/* On entry, LDA specifies the first dimension of A as declared */ |
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/* in the calling (sub) program. LDA must be at least */ |
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/* max( 1, m ). */ |
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/* Unchanged on exit. */ |
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/* Level 2 Blas routine. */ |
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/* -- Written on 22-October-1986. */ |
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/* Jack Dongarra, Argonne National Lab. */ |
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/* Jeremy Du Croz, Nag Central Office. */ |
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/* Sven Hammarling, Nag Central Office. */ |
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/* Richard Hanson, Sandia National Labs. */ |
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/* .. Parameters .. */ |
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/* .. */ |
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/* .. Local Scalars .. */ |
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/* .. */ |
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/* .. External Subroutines .. */ |
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/* .. */ |
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/* .. Intrinsic Functions .. */ |
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/* .. */ |
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/* Test the input parameters. */ |
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/* Function Body */ |
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integer i, j, m = *_m, n = *_n, incx = *_incx, incy = *_incy, lda = *_lda; |
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doublereal alpha = *_alpha; |
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integer info = 0; |
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if (m < 0) |
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info = 1; |
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else if (n < 0) |
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info = 2; |
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else if (incx == 0) |
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info = 5; |
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else if (incy == 0) |
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info = 7; |
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else if (lda < max(1,m)) |
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info = 9; |
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if (info != 0) |
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{ |
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xerbla_("DGER ", &info); |
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return 0; |
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} |
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if (incx < 0) |
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x -= (m-1)*incx; |
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if (incy < 0) |
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y -= (n-1)*incy; |
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/* Start the operations. In this version the elements of A are */ |
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/* accessed sequentially with one pass through A. */ |
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if( alpha == 0 ) |
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; |
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else if( incx == 1 ) |
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{ |
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for( j = 0; j < n; j++, a += lda ) |
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{ |
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doublereal s = y[j*incy]; |
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if( s == 0 ) |
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continue; |
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s *= alpha; |
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for( i = 0; i <= m - 2; i += 2 ) |
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{ |
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doublereal t0 = a[i] + x[i]*s; |
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doublereal t1 = a[i+1] + x[i+1]*s; |
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a[i] = t0; a[i+1] = t1; |
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} |
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for( ; i < m; i++ ) |
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a[i] += x[i]*s; |
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} |
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} |
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else |
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{ |
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for( j = 0; j < n; j++, a += lda ) |
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{ |
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doublereal s = y[j*incy]; |
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if( s == 0 ) |
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continue; |
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s *= alpha; |
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for( i = 0; i < m; i++ ) |
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a[i] += x[i*incx]*s; |
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} |
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} |
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return 0; |
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/* End of DGER . */ |
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} /* dger_ */
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