/*  -- translated by f2c (version 19940927).

   You must link the resulting object file with the libraries:

	-lf2c -lm   (in that order)

*/

#include "f2c.h"

/* Subroutine */ int sgemv_(char *trans, integer *m, integer *n, real *alpha, 

	real *a, integer *lda, real *x, integer *incx, real *beta, real *y, 

	integer *incy)

{

    /* System generated locals */

    integer a_dim1, a_offset, i__1, i__2;

    /* Local variables */

    static integer info;

    static real temp;

    static integer lenx, leny, i, j;

    extern logical lsame_(char *, char *);

    static integer ix, iy, jx, jy, kx, ky;

    extern /* Subroutine */ int xerbla_(char *, integer *);

/*  Purpose   

    =======   

    SGEMV  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.   

    Parameters   

    ==========   

    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  - REAL            .   

             On entry, ALPHA specifies the scalar alpha.   

             Unchanged on exit.   

    A      - REAL             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      - REAL             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   - REAL            .   

             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      - REAL             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.   

    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.   

       Test the input parameters.   

   Parameter adjustments   

       Function Body */

#define X(I) x[(I)-1]

#define Y(I) y[(I)-1]

#define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]

    info = 0;

    if (! lsame_(trans, "N") && ! lsame_(trans, "T") && ! 

	    lsame_(trans, "C")) {

	info = 1;

    } else if (*m < 0) {

	info = 2;

    } else if (*n < 0) {

	info = 3;

    } else if (*lda < max(1,*m)) {

	info = 6;

    } else if (*incx == 0) {

	info = 8;

    } else if (*incy == 0) {

	info = 11;

    }

    if (info != 0) {

	xerbla_("SGEMV ", &info);

	return 0;

    }

/*     Quick return if possible. */

    if (*m == 0 || *n == 0 || *alpha == 0.f && *beta == 1.f) {

	return 0;

    }

/*     Set  LENX  and  LENY, the lengths of the vectors x and y, and set 

       up the start points in  X  and  Y. */

    if (lsame_(trans, "N")) {

	lenx = *n;

	leny = *m;

    } else {

	lenx = *m;

	leny = *n;

    }

    if (*incx > 0) {

	kx = 1;

    } else {

	kx = 1 - (lenx - 1) * *incx;

    }

    if (*incy > 0) {

	ky = 1;

    } else {

	ky = 1 - (leny - 1) * *incy;

    }

/*     Start the operations. In this version the elements of A are   

       accessed sequentially with one pass through A.   

       First form  y := beta*y. */

    if (*beta != 1.f) {

	if (*incy == 1) {

	    if (*beta == 0.f) {

		i__1 = leny;

		for (i = 1; i <= leny; ++i) {

		    Y(i) = 0.f;

/* L10: */

		}

	    } else {

		i__1 = leny;

		for (i = 1; i <= leny; ++i) {

		    Y(i) = *beta * Y(i);

/* L20: */

		}

	    }

	} else {

	    iy = ky;

	    if (*beta == 0.f) {

		i__1 = leny;

		for (i = 1; i <= leny; ++i) {

		    Y(iy) = 0.f;

		    iy += *incy;

/* L30: */

		}

	    } else {

		i__1 = leny;

		for (i = 1; i <= leny; ++i) {

		    Y(iy) = *beta * Y(iy);

		    iy += *incy;

/* L40: */

		}

	    }

	}

    }

    if (*alpha == 0.f) {

	return 0;

    }

    if (lsame_(trans, "N")) {

/*        Form  y := alpha*A*x + y. */

	jx = kx;

	if (*incy == 1) {

	    i__1 = *n;

	    for (j = 1; j <= *n; ++j) {

		if (X(jx) != 0.f) {

		    temp = *alpha * X(jx);

		    i__2 = *m;

		    for (i = 1; i <= *m; ++i) {

			Y(i) += temp * A(i,j);

/* L50: */

		    }

		}

		jx += *incx;

/* L60: */

	    }

	} else {

	    i__1 = *n;

	    for (j = 1; j <= *n; ++j) {

		if (X(jx) != 0.f) {

		    temp = *alpha * X(jx);

		    iy = ky;

		    i__2 = *m;

		    for (i = 1; i <= *m; ++i) {

			Y(iy) += temp * A(i,j);

			iy += *incy;

/* L70: */

		    }

		}

		jx += *incx;

/* L80: */

	    }

	}

    } else {

/*        Form  y := alpha*A'*x + y. */

	jy = ky;

	if (*incx == 1) {

	    i__1 = *n;

	    for (j = 1; j <= *n; ++j) {

		temp = 0.f;

		i__2 = *m;

		for (i = 1; i <= *m; ++i) {

		    temp += A(i,j) * X(i);

/* L90: */

		}

		Y(jy) += *alpha * temp;

		jy += *incy;

/* L100: */

	    }

	} else {

	    i__1 = *n;

	    for (j = 1; j <= *n; ++j) {

		temp = 0.f;

		ix = kx;

		i__2 = *m;

		for (i = 1; i <= *m; ++i) {

		    temp += A(i,j) * X(ix);

		    ix += *incx;

/* L110: */

		}

		Y(jy) += *alpha * temp;

		jy += *incy;

/* L120: */

	    }

	}

    }

    return 0;

/*     End of SGEMV . */

} /* sgemv_ */