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

   You must link the resulting object file with the libraries:

	-lf2c -lm   (in that order)

*/

#include "f2c.h"

/* Table of constant values */

static complex c_b1 = {0.f,0.f};

static complex c_b2 = {1.f,0.f};

static integer c__3 = 3;

static integer c__1 = 1;

/* Subroutine */ int clagsy_(integer *n, integer *k, real *d, complex *a, 

	integer *lda, integer *iseed, complex *work, integer *info)

{

    /* System generated locals */

    integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5, i__6, i__7, i__8, 

	    i__9;

    doublereal d__1;

    complex q__1, q__2, q__3, q__4;

    /* Builtin functions */

    double c_abs(complex *);

    void c_div(complex *, complex *, complex *);

    /* Local variables */

    static integer i, j;

    extern /* Subroutine */ int cgerc_(integer *, integer *, complex *, 

	    complex *, integer *, complex *, integer *, complex *, integer *);

    static complex alpha;

    extern /* Subroutine */ int cscal_(integer *, complex *, complex *, 

	    integer *);

    extern /* Complex */ VOID cdotc_(complex *, integer *, complex *, integer 

	    *, complex *, integer *);

    extern /* Subroutine */ int cgemv_(char *, integer *, integer *, complex *

	    , complex *, integer *, complex *, integer *, complex *, complex *

	    , integer *), caxpy_(integer *, complex *, complex *, 

	    integer *, complex *, integer *), csymv_(char *, integer *, 

	    complex *, complex *, integer *, complex *, integer *, complex *, 

	    complex *, integer *);

    extern real scnrm2_(integer *, complex *, integer *);

    static integer ii, jj;

    static complex wa, wb;

    extern /* Subroutine */ int clacgv_(integer *, complex *, integer *);

    static real wn;

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

	    integer *, integer *, integer *, complex *);

    static complex tau;

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

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

       Courant Institute, Argonne National Lab, and Rice University   

       September 30, 1994   

    Purpose   

    =======   

    CLAGSY generates a complex symmetric matrix A, by pre- and post-   

    multiplying a real diagonal matrix D with a random unitary matrix:   

    A = U*D*U**T. The semi-bandwidth may then be reduced to k by   

    additional unitary transformations.   

    Arguments   

    =========   

    N       (input) INTEGER   

            The order of the matrix A.  N >= 0.   

    K       (input) INTEGER   

            The number of nonzero subdiagonals within the band of A.   

            0 <= K <= N-1.   

    D       (input) REAL array, dimension (N)   

            The diagonal elements of the diagonal matrix D.   

    A       (output) COMPLEX array, dimension (LDA,N)   

            The generated n by n symmetric matrix A (the full matrix is   

            stored).   

    LDA     (input) INTEGER   

            The leading dimension of the array A.  LDA >= N.   

    ISEED   (input/output) INTEGER array, dimension (4)   

            On entry, the seed of the random number generator; the array 

            elements must be between 0 and 4095, and ISEED(4) must be   

            odd.   

            On exit, the seed is updated.   

    WORK    (workspace) COMPLEX array, dimension (2*N)   

    INFO    (output) INTEGER   

            = 0: successful exit   

            < 0: if INFO = -i, the i-th argument had an illegal value   

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

       Test the input arguments   

       Parameter adjustments */

    --d;

    a_dim1 = *lda;

    a_offset = a_dim1 + 1;

    a -= a_offset;

    --iseed;

    --work;

    /* Function Body */

    *info = 0;

    if (*n < 0) {

	*info = -1;

    } else if (*k < 0 || *k > *n - 1) {

	*info = -2;

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

	*info = -5;

    }

    if (*info < 0) {

	i__1 = -(*info);

	xerbla_("CLAGSY", &i__1);

	return 0;

    }

/*     initialize lower triangle of A to diagonal matrix */

    i__1 = *n;

    for (j = 1; j <= i__1; ++j) {

	i__2 = *n;

	for (i = j + 1; i <= i__2; ++i) {

	    i__3 = i + j * a_dim1;

	    a[i__3].r = 0.f, a[i__3].i = 0.f;

/* L10: */

	}

/* L20: */

    }

    i__1 = *n;

    for (i = 1; i <= i__1; ++i) {

	i__2 = i + i * a_dim1;

	i__3 = i;

	a[i__2].r = d[i__3], a[i__2].i = 0.f;

/* L30: */

    }

/*     Generate lower triangle of symmetric matrix */

    for (i = *n - 1; i >= 1; --i) {

/*        generate random reflection */

	i__1 = *n - i + 1;

	clarnv_(&c__3, &iseed[1], &i__1, &work[1]);

	i__1 = *n - i + 1;

	wn = scnrm2_(&i__1, &work[1], &c__1);

	d__1 = wn / c_abs(&work[1]);

	q__1.r = d__1 * work[1].r, q__1.i = d__1 * work[1].i;

	wa.r = q__1.r, wa.i = q__1.i;

	if (wn == 0.f) {

	    tau.r = 0.f, tau.i = 0.f;

	} else {

	    q__1.r = work[1].r + wa.r, q__1.i = work[1].i + wa.i;

	    wb.r = q__1.r, wb.i = q__1.i;

	    i__1 = *n - i;

	    c_div(&q__1, &c_b2, &wb);

	    cscal_(&i__1, &q__1, &work[2], &c__1);

	    work[1].r = 1.f, work[1].i = 0.f;

	    c_div(&q__1, &wb, &wa);

	    d__1 = q__1.r;

	    tau.r = d__1, tau.i = 0.f;

	}

/*        apply random reflection to A(i:n,i:n) from the left   

          and the right   

          compute  y := tau * A * conjg(u) */

	i__1 = *n - i + 1;

	clacgv_(&i__1, &work[1], &c__1);

	i__1 = *n - i + 1;

	csymv_("Lower", &i__1, &tau, &a[i + i * a_dim1], lda, &work[1], &c__1,

		 &c_b1, &work[*n + 1], &c__1);

	i__1 = *n - i + 1;

	clacgv_(&i__1, &work[1], &c__1);

/*        compute  v := y - 1/2 * tau * ( u, y ) * u */

	q__3.r = -.5f, q__3.i = 0.f;

	q__2.r = q__3.r * tau.r - q__3.i * tau.i, q__2.i = q__3.r * tau.i + 

		q__3.i * tau.r;

	i__1 = *n - i + 1;

	cdotc_(&q__4, &i__1, &work[1], &c__1, &work[*n + 1], &c__1);

	q__1.r = q__2.r * q__4.r - q__2.i * q__4.i, q__1.i = q__2.r * q__4.i 

		+ q__2.i * q__4.r;

	alpha.r = q__1.r, alpha.i = q__1.i;

	i__1 = *n - i + 1;

	caxpy_(&i__1, &alpha, &work[1], &c__1, &work[*n + 1], &c__1);

/*        apply the transformation as a rank-2 update to A(i:n,i:n)   

          CALL CSYR2( 'Lower', N-I+1, -ONE, WORK, 1, WORK( N+1 ), 1, 

          $               A( I, I ), LDA ) */

	i__1 = *n;

	for (jj = i; jj <= i__1; ++jj) {

	    i__2 = *n;

	    for (ii = jj; ii <= i__2; ++ii) {

		i__3 = ii + jj * a_dim1;

		i__4 = ii + jj * a_dim1;

		i__5 = ii - i + 1;

		i__6 = *n + jj - i + 1;

		q__3.r = work[i__5].r * work[i__6].r - work[i__5].i * work[

			i__6].i, q__3.i = work[i__5].r * work[i__6].i + work[

			i__5].i * work[i__6].r;

		q__2.r = a[i__4].r - q__3.r, q__2.i = a[i__4].i - q__3.i;

		i__7 = *n + ii - i + 1;

		i__8 = jj - i + 1;

		q__4.r = work[i__7].r * work[i__8].r - work[i__7].i * work[

			i__8].i, q__4.i = work[i__7].r * work[i__8].i + work[

			i__7].i * work[i__8].r;

		q__1.r = q__2.r - q__4.r, q__1.i = q__2.i - q__4.i;

		a[i__3].r = q__1.r, a[i__3].i = q__1.i;

/* L40: */

	    }

/* L50: */

	}

/* L60: */

    }

/*     Reduce number of subdiagonals to K */

    i__1 = *n - 1 - *k;

    for (i = 1; i <= i__1; ++i) {

/*        generate reflection to annihilate A(k+i+1:n,i) */

	i__2 = *n - *k - i + 1;

	wn = scnrm2_(&i__2, &a[*k + i + i * a_dim1], &c__1);

	d__1 = wn / c_abs(&a[*k + i + i * a_dim1]);

	i__2 = *k + i + i * a_dim1;

	q__1.r = d__1 * a[i__2].r, q__1.i = d__1 * a[i__2].i;

	wa.r = q__1.r, wa.i = q__1.i;

	if (wn == 0.f) {

	    tau.r = 0.f, tau.i = 0.f;

	} else {

	    i__2 = *k + i + i * a_dim1;

	    q__1.r = a[i__2].r + wa.r, q__1.i = a[i__2].i + wa.i;

	    wb.r = q__1.r, wb.i = q__1.i;

	    i__2 = *n - *k - i;

	    c_div(&q__1, &c_b2, &wb);

	    cscal_(&i__2, &q__1, &a[*k + i + 1 + i * a_dim1], &c__1);

	    i__2 = *k + i + i * a_dim1;

	    a[i__2].r = 1.f, a[i__2].i = 0.f;

	    c_div(&q__1, &wb, &wa);

	    d__1 = q__1.r;

	    tau.r = d__1, tau.i = 0.f;

	}

/*        apply reflection to A(k+i:n,i+1:k+i-1) from the left */

	i__2 = *n - *k - i + 1;

	i__3 = *k - 1;

	cgemv_("Conjugate transpose", &i__2, &i__3, &c_b2, &a[*k + i + (i + 1)

		 * a_dim1], lda, &a[*k + i + i * a_dim1], &c__1, &c_b1, &work[

		1], &c__1);

	i__2 = *n - *k - i + 1;

	i__3 = *k - 1;

	q__1.r = -(doublereal)tau.r, q__1.i = -(doublereal)tau.i;

	cgerc_(&i__2, &i__3, &q__1, &a[*k + i + i * a_dim1], &c__1, &work[1], 

		&c__1, &a[*k + i + (i + 1) * a_dim1], lda);

/*        apply reflection to A(k+i:n,k+i:n) from the left and the rig

ht   

          compute  y := tau * A * conjg(u) */

	i__2 = *n - *k - i + 1;

	clacgv_(&i__2, &a[*k + i + i * a_dim1], &c__1);

	i__2 = *n - *k - i + 1;

	csymv_("Lower", &i__2, &tau, &a[*k + i + (*k + i) * a_dim1], lda, &a[*

		k + i + i * a_dim1], &c__1, &c_b1, &work[1], &c__1);

	i__2 = *n - *k - i + 1;

	clacgv_(&i__2, &a[*k + i + i * a_dim1], &c__1);

/*        compute  v := y - 1/2 * tau * ( u, y ) * u */

	q__3.r = -.5f, q__3.i = 0.f;

	q__2.r = q__3.r * tau.r - q__3.i * tau.i, q__2.i = q__3.r * tau.i + 

		q__3.i * tau.r;

	i__2 = *n - *k - i + 1;

	cdotc_(&q__4, &i__2, &a[*k + i + i * a_dim1], &c__1, &work[1], &c__1);

	q__1.r = q__2.r * q__4.r - q__2.i * q__4.i, q__1.i = q__2.r * q__4.i 

		+ q__2.i * q__4.r;

	alpha.r = q__1.r, alpha.i = q__1.i;

	i__2 = *n - *k - i + 1;

	caxpy_(&i__2, &alpha, &a[*k + i + i * a_dim1], &c__1, &work[1], &c__1)

		;

/*        apply symmetric rank-2 update to A(k+i:n,k+i:n)   

          CALL CSYR2( 'Lower', N-K-I+1, -ONE, A( K+I, I ), 1, WORK, 1,

          $               A( K+I, K+I ), LDA ) */

	i__2 = *n;

	for (jj = *k + i; jj <= i__2; ++jj) {

	    i__3 = *n;

	    for (ii = jj; ii <= i__3; ++ii) {

		i__4 = ii + jj * a_dim1;

		i__5 = ii + jj * a_dim1;

		i__6 = ii + i * a_dim1;

		i__7 = jj - *k - i + 1;

		q__3.r = a[i__6].r * work[i__7].r - a[i__6].i * work[i__7].i, 

			q__3.i = a[i__6].r * work[i__7].i + a[i__6].i * work[

			i__7].r;

		q__2.r = a[i__5].r - q__3.r, q__2.i = a[i__5].i - q__3.i;

		i__8 = ii - *k - i + 1;

		i__9 = jj + i * a_dim1;

		q__4.r = work[i__8].r * a[i__9].r - work[i__8].i * a[i__9].i, 

			q__4.i = work[i__8].r * a[i__9].i + work[i__8].i * a[

			i__9].r;

		q__1.r = q__2.r - q__4.r, q__1.i = q__2.i - q__4.i;

		a[i__4].r = q__1.r, a[i__4].i = q__1.i;

/* L70: */

	    }

/* L80: */

	}

	i__2 = *k + i + i * a_dim1;

	q__1.r = -(doublereal)wa.r, q__1.i = -(doublereal)wa.i;

	a[i__2].r = q__1.r, a[i__2].i = q__1.i;

	i__2 = *n;

	for (j = *k + i + 1; j <= i__2; ++j) {

	    i__3 = j + i * a_dim1;

	    a[i__3].r = 0.f, a[i__3].i = 0.f;

/* L90: */

	}

/* L100: */

    }

/*     Store full symmetric matrix */

    i__1 = *n;

    for (j = 1; j <= i__1; ++j) {

	i__2 = *n;

	for (i = j + 1; i <= i__2; ++i) {

	    i__3 = j + i * a_dim1;

	    i__4 = i + j * a_dim1;

	    a[i__3].r = a[i__4].r, a[i__3].i = a[i__4].i;

/* L110: */

	}

/* L120: */

    }

    return 0;

/*     End of CLAGSY */

} /* clagsy_ */