#include "f2c.h"

/* Subroutine */ int zsymv_(char *uplo, integer *n, doublecomplex *alpha, 

	doublecomplex *a, integer *lda, doublecomplex *x, integer *incx, 

	doublecomplex *beta, doublecomplex *y, integer *incy)

{

/*  -- LAPACK auxiliary routine (version 2.0) --   

       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   

       Courant Institute, Argonne National Lab, and Rice University   

       October 31, 1992   

    Purpose   

    =======   

    ZSYMV  performs the matrix-vector  operation   

       y := alpha*A*x + beta*y,   

    where alpha and beta are scalars, x and y are n element vectors and   

    A is an n by n symmetric matrix.   

    Arguments   

    ==========   

    UPLO   - CHARACTER*1   

             On entry, UPLO specifies whether the upper or lower   

             triangular part of the array A is to be referenced as   

             follows:   

                UPLO = 'U' or 'u'   Only the upper triangular part of A   

                                    is to be referenced.   

                UPLO = 'L' or 'l'   Only the lower triangular part of A   

                                    is to be referenced.   

             Unchanged on exit.   

    N      - INTEGER   

             On entry, N specifies the order of the matrix A.   

             N must be at least zero.   

             Unchanged on exit.   

    ALPHA  - COMPLEX*16   

             On entry, ALPHA specifies the scalar alpha.   

             Unchanged on exit.   

    A      - COMPLEX*16 array, dimension ( LDA, N )   

             Before entry, with  UPLO = 'U' or 'u', the leading n by n   

             upper triangular part of the array A must contain the upper 

             triangular part of the symmetric matrix and the strictly   

             lower triangular part of A is not referenced.   

             Before entry, with UPLO = 'L' or 'l', the leading n by n   

             lower triangular part of the array A must contain the lower 

             triangular part of the symmetric matrix and the strictly   

             upper triangular part of A is not referenced.   

             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, N ).   

             Unchanged on exit.   

    X      - COMPLEX*16 array, dimension at least   

             ( 1 + ( N - 1 )*abs( INCX ) ).   

             Before entry, the incremented array X must contain the N-   

             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.   

    BETA   - COMPLEX*16   

             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      - COMPLEX*16 array, dimension at least   

             ( 1 + ( N - 1 )*abs( INCY ) ).   

             Before entry, the incremented array Y must contain the n   

             element 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.   

   ===================================================================== 

       Test the input parameters.   

   Parameter adjustments   

       Function Body */

    /* System generated locals */

    integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5;

    doublecomplex z__1, z__2, z__3, z__4;

    /* Local variables */

    static integer info;

    static doublecomplex temp1, temp2;

    static integer i, j;

    extern logical lsame_(char *, char *);

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

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

#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_(uplo, "U") && ! lsame_(uplo, "L")) {

	info = 1;

    } else if (*n < 0) {

	info = 2;

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

	info = 5;

    } else if (*incx == 0) {

	info = 7;

    } else if (*incy == 0) {

	info = 10;

    }

    if (info != 0) {

	xerbla_("ZSYMV ", &info);

	return 0;

    }

/*     Quick return if possible. */

    if (*n == 0 || alpha->r == 0. && alpha->i == 0. && (beta->r == 1. && 

	    beta->i == 0.)) {

	return 0;

    }

/*     Set up the start points in  X  and  Y. */

    if (*incx > 0) {

	kx = 1;

    } else {

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

    }

    if (*incy > 0) {

	ky = 1;

    } else {

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

    }

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

       accessed sequentially with one pass through the triangular part   

       of A.   

       First form  y := beta*y. */

    if (beta->r != 1. || beta->i != 0.) {

	if (*incy == 1) {

	    if (beta->r == 0. && beta->i == 0.) {

		i__1 = *n;

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

		    i__2 = i;

		    Y(i).r = 0., Y(i).i = 0.;

/* L10: */

		}

	    } else {

		i__1 = *n;

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

		    i__2 = i;

		    i__3 = i;

		    z__1.r = beta->r * Y(i).r - beta->i * Y(i).i, 

			    z__1.i = beta->r * Y(i).i + beta->i * Y(i)

			    .r;

		    Y(i).r = z__1.r, Y(i).i = z__1.i;

/* L20: */

		}

	    }

	} else {

	    iy = ky;

	    if (beta->r == 0. && beta->i == 0.) {

		i__1 = *n;

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

		    i__2 = iy;

		    Y(iy).r = 0., Y(iy).i = 0.;

		    iy += *incy;

/* L30: */

		}

	    } else {

		i__1 = *n;

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

		    i__2 = iy;

		    i__3 = iy;

		    z__1.r = beta->r * Y(iy).r - beta->i * Y(iy).i, 

			    z__1.i = beta->r * Y(iy).i + beta->i * Y(iy)

			    .r;

		    Y(iy).r = z__1.r, Y(iy).i = z__1.i;

		    iy += *incy;

/* L40: */

		}

	    }

	}

    }

    if (alpha->r == 0. && alpha->i == 0.) {

	return 0;

    }

    if (lsame_(uplo, "U")) {

/*        Form  y  when A is stored in upper triangle. */

	if (*incx == 1 && *incy == 1) {

	    i__1 = *n;

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

		i__2 = j;

		z__1.r = alpha->r * X(j).r - alpha->i * X(j).i, z__1.i =

			 alpha->r * X(j).i + alpha->i * X(j).r;

		temp1.r = z__1.r, temp1.i = z__1.i;

		temp2.r = 0., temp2.i = 0.;

		i__2 = j - 1;

		for (i = 1; i <= j-1; ++i) {

		    i__3 = i;

		    i__4 = i;

		    i__5 = i + j * a_dim1;

		    z__2.r = temp1.r * A(i,j).r - temp1.i * A(i,j).i, 

			    z__2.i = temp1.r * A(i,j).i + temp1.i * A(i,j)

			    .r;

		    z__1.r = Y(i).r + z__2.r, z__1.i = Y(i).i + z__2.i;

		    Y(i).r = z__1.r, Y(i).i = z__1.i;

		    i__3 = i + j * a_dim1;

		    i__4 = i;

		    z__2.r = A(i,j).r * X(i).r - A(i,j).i * X(i).i, 

			    z__2.i = A(i,j).r * X(i).i + A(i,j).i * X(

			    i).r;

		    z__1.r = temp2.r + z__2.r, z__1.i = temp2.i + z__2.i;

		    temp2.r = z__1.r, temp2.i = z__1.i;

/* L50: */

		}

		i__2 = j;

		i__3 = j;

		i__4 = j + j * a_dim1;

		z__3.r = temp1.r * A(j,j).r - temp1.i * A(j,j).i, z__3.i = 

			temp1.r * A(j,j).i + temp1.i * A(j,j).r;

		z__2.r = Y(j).r + z__3.r, z__2.i = Y(j).i + z__3.i;

		z__4.r = alpha->r * temp2.r - alpha->i * temp2.i, z__4.i = 

			alpha->r * temp2.i + alpha->i * temp2.r;

		z__1.r = z__2.r + z__4.r, z__1.i = z__2.i + z__4.i;

		Y(j).r = z__1.r, Y(j).i = z__1.i;

/* L60: */

	    }

	} else {

	    jx = kx;

	    jy = ky;

	    i__1 = *n;

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

		i__2 = jx;

		z__1.r = alpha->r * X(jx).r - alpha->i * X(jx).i, z__1.i =

			 alpha->r * X(jx).i + alpha->i * X(jx).r;

		temp1.r = z__1.r, temp1.i = z__1.i;

		temp2.r = 0., temp2.i = 0.;

		ix = kx;

		iy = ky;

		i__2 = j - 1;

		for (i = 1; i <= j-1; ++i) {

		    i__3 = iy;

		    i__4 = iy;

		    i__5 = i + j * a_dim1;

		    z__2.r = temp1.r * A(i,j).r - temp1.i * A(i,j).i, 

			    z__2.i = temp1.r * A(i,j).i + temp1.i * A(i,j)

			    .r;

		    z__1.r = Y(iy).r + z__2.r, z__1.i = Y(iy).i + z__2.i;

		    Y(iy).r = z__1.r, Y(iy).i = z__1.i;

		    i__3 = i + j * a_dim1;

		    i__4 = ix;

		    z__2.r = A(i,j).r * X(ix).r - A(i,j).i * X(ix).i, 

			    z__2.i = A(i,j).r * X(ix).i + A(i,j).i * X(

			    ix).r;

		    z__1.r = temp2.r + z__2.r, z__1.i = temp2.i + z__2.i;

		    temp2.r = z__1.r, temp2.i = z__1.i;

		    ix += *incx;

		    iy += *incy;

/* L70: */

		}

		i__2 = jy;

		i__3 = jy;

		i__4 = j + j * a_dim1;

		z__3.r = temp1.r * A(j,j).r - temp1.i * A(j,j).i, z__3.i = 

			temp1.r * A(j,j).i + temp1.i * A(j,j).r;

		z__2.r = Y(jy).r + z__3.r, z__2.i = Y(jy).i + z__3.i;

		z__4.r = alpha->r * temp2.r - alpha->i * temp2.i, z__4.i = 

			alpha->r * temp2.i + alpha->i * temp2.r;

		z__1.r = z__2.r + z__4.r, z__1.i = z__2.i + z__4.i;

		Y(jy).r = z__1.r, Y(jy).i = z__1.i;

		jx += *incx;

		jy += *incy;

/* L80: */

	    }

	}

    } else {

/*        Form  y  when A is stored in lower triangle. */

	if (*incx == 1 && *incy == 1) {

	    i__1 = *n;

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

		i__2 = j;

		z__1.r = alpha->r * X(j).r - alpha->i * X(j).i, z__1.i =

			 alpha->r * X(j).i + alpha->i * X(j).r;

		temp1.r = z__1.r, temp1.i = z__1.i;

		temp2.r = 0., temp2.i = 0.;

		i__2 = j;

		i__3 = j;

		i__4 = j + j * a_dim1;

		z__2.r = temp1.r * A(j,j).r - temp1.i * A(j,j).i, z__2.i = 

			temp1.r * A(j,j).i + temp1.i * A(j,j).r;

		z__1.r = Y(j).r + z__2.r, z__1.i = Y(j).i + z__2.i;

		Y(j).r = z__1.r, Y(j).i = z__1.i;

		i__2 = *n;

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

		    i__3 = i;

		    i__4 = i;

		    i__5 = i + j * a_dim1;

		    z__2.r = temp1.r * A(i,j).r - temp1.i * A(i,j).i, 

			    z__2.i = temp1.r * A(i,j).i + temp1.i * A(i,j)

			    .r;

		    z__1.r = Y(i).r + z__2.r, z__1.i = Y(i).i + z__2.i;

		    Y(i).r = z__1.r, Y(i).i = z__1.i;

		    i__3 = i + j * a_dim1;

		    i__4 = i;

		    z__2.r = A(i,j).r * X(i).r - A(i,j).i * X(i).i, 

			    z__2.i = A(i,j).r * X(i).i + A(i,j).i * X(

			    i).r;

		    z__1.r = temp2.r + z__2.r, z__1.i = temp2.i + z__2.i;

		    temp2.r = z__1.r, temp2.i = z__1.i;

/* L90: */

		}

		i__2 = j;

		i__3 = j;

		z__2.r = alpha->r * temp2.r - alpha->i * temp2.i, z__2.i = 

			alpha->r * temp2.i + alpha->i * temp2.r;

		z__1.r = Y(j).r + z__2.r, z__1.i = Y(j).i + z__2.i;

		Y(j).r = z__1.r, Y(j).i = z__1.i;

/* L100: */

	    }

	} else {

	    jx = kx;

	    jy = ky;

	    i__1 = *n;

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

		i__2 = jx;

		z__1.r = alpha->r * X(jx).r - alpha->i * X(jx).i, z__1.i =

			 alpha->r * X(jx).i + alpha->i * X(jx).r;

		temp1.r = z__1.r, temp1.i = z__1.i;

		temp2.r = 0., temp2.i = 0.;

		i__2 = jy;

		i__3 = jy;

		i__4 = j + j * a_dim1;

		z__2.r = temp1.r * A(j,j).r - temp1.i * A(j,j).i, z__2.i = 

			temp1.r * A(j,j).i + temp1.i * A(j,j).r;

		z__1.r = Y(jy).r + z__2.r, z__1.i = Y(jy).i + z__2.i;

		Y(jy).r = z__1.r, Y(jy).i = z__1.i;

		ix = jx;

		iy = jy;

		i__2 = *n;

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

		    ix += *incx;

		    iy += *incy;

		    i__3 = iy;

		    i__4 = iy;

		    i__5 = i + j * a_dim1;

		    z__2.r = temp1.r * A(i,j).r - temp1.i * A(i,j).i, 

			    z__2.i = temp1.r * A(i,j).i + temp1.i * A(i,j)

			    .r;

		    z__1.r = Y(iy).r + z__2.r, z__1.i = Y(iy).i + z__2.i;

		    Y(iy).r = z__1.r, Y(iy).i = z__1.i;

		    i__3 = i + j * a_dim1;

		    i__4 = ix;

		    z__2.r = A(i,j).r * X(ix).r - A(i,j).i * X(ix).i, 

			    z__2.i = A(i,j).r * X(ix).i + A(i,j).i * X(

			    ix).r;

		    z__1.r = temp2.r + z__2.r, z__1.i = temp2.i + z__2.i;

		    temp2.r = z__1.r, temp2.i = z__1.i;

/* L110: */

		}

		i__2 = jy;

		i__3 = jy;

		z__2.r = alpha->r * temp2.r - alpha->i * temp2.i, z__2.i = 

			alpha->r * temp2.i + alpha->i * temp2.r;

		z__1.r = Y(jy).r + z__2.r, z__1.i = Y(jy).i + z__2.i;

		Y(jy).r = z__1.r, Y(jy).i = z__1.i;

		jx += *incx;

		jy += *incy;

/* L120: */

	    }

	}

    }

    return 0;

/*     End of ZSYMV */

} /* zsymv_ */