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authorshmel1k <shmel1k@ydb.tech>2022-09-02 12:44:59 +0300
committershmel1k <shmel1k@ydb.tech>2022-09-02 12:44:59 +0300
commit90d450f74722da7859d6f510a869f6c6908fd12f (patch)
tree538c718dedc76cdfe37ad6d01ff250dd930d9278 /contrib/libs/clapack/zsytf2.c
parent01f64c1ecd0d4ffa9e3a74478335f1745f26cc75 (diff)
downloadydb-90d450f74722da7859d6f510a869f6c6908fd12f.tar.gz
[] add metering mode to CLI
Diffstat (limited to 'contrib/libs/clapack/zsytf2.c')
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1 files changed, 727 insertions, 0 deletions
diff --git a/contrib/libs/clapack/zsytf2.c b/contrib/libs/clapack/zsytf2.c
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+/* zsytf2.f -- translated by f2c (version 20061008).
+ You must link the resulting object file with libf2c:
+ on Microsoft Windows system, link with libf2c.lib;
+ on Linux or Unix systems, link with .../path/to/libf2c.a -lm
+ or, if you install libf2c.a in a standard place, with -lf2c -lm
+ -- in that order, at the end of the command line, as in
+ cc *.o -lf2c -lm
+ Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
+
+ http://www.netlib.org/f2c/libf2c.zip
+*/
+
+#include "f2c.h"
+#include "blaswrap.h"
+
+/* Table of constant values */
+
+static doublecomplex c_b1 = {1.,0.};
+static integer c__1 = 1;
+
+/* Subroutine */ int zsytf2_(char *uplo, integer *n, doublecomplex *a,
+ integer *lda, integer *ipiv, integer *info)
+{
+ /* System generated locals */
+ integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5, i__6;
+ doublereal d__1, d__2, d__3, d__4;
+ doublecomplex z__1, z__2, z__3, z__4;
+
+ /* Builtin functions */
+ double sqrt(doublereal), d_imag(doublecomplex *);
+ void z_div(doublecomplex *, doublecomplex *, doublecomplex *);
+
+ /* Local variables */
+ integer i__, j, k;
+ doublecomplex t, r1, d11, d12, d21, d22;
+ integer kk, kp;
+ doublecomplex wk, wkm1, wkp1;
+ integer imax, jmax;
+ extern /* Subroutine */ int zsyr_(char *, integer *, doublecomplex *,
+ doublecomplex *, integer *, doublecomplex *, integer *);
+ doublereal alpha;
+ extern logical lsame_(char *, char *);
+ extern /* Subroutine */ int zscal_(integer *, doublecomplex *,
+ doublecomplex *, integer *);
+ integer kstep;
+ logical upper;
+ extern /* Subroutine */ int zswap_(integer *, doublecomplex *, integer *,
+ doublecomplex *, integer *);
+ doublereal absakk;
+ extern logical disnan_(doublereal *);
+ extern /* Subroutine */ int xerbla_(char *, integer *);
+ doublereal colmax;
+ extern integer izamax_(integer *, doublecomplex *, integer *);
+ doublereal rowmax;
+
+
+/* -- LAPACK routine (version 3.2) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/* November 2006 */
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* ZSYTF2 computes the factorization of a complex symmetric matrix A */
+/* using the Bunch-Kaufman diagonal pivoting method: */
+
+/* A = U*D*U' or A = L*D*L' */
+
+/* where U (or L) is a product of permutation and unit upper (lower) */
+/* triangular matrices, U' is the transpose of U, and D is symmetric and */
+/* block diagonal with 1-by-1 and 2-by-2 diagonal blocks. */
+
+/* This is the unblocked version of the algorithm, calling Level 2 BLAS. */
+
+/* Arguments */
+/* ========= */
+
+/* UPLO (input) CHARACTER*1 */
+/* Specifies whether the upper or lower triangular part of the */
+/* symmetric matrix A is stored: */
+/* = 'U': Upper triangular */
+/* = 'L': Lower triangular */
+
+/* N (input) INTEGER */
+/* The order of the matrix A. N >= 0. */
+
+/* A (input/output) COMPLEX*16 array, dimension (LDA,N) */
+/* On entry, the symmetric matrix A. If UPLO = 'U', the leading */
+/* n-by-n upper triangular part of A contains the upper */
+/* triangular part of the matrix A, and the strictly lower */
+/* triangular part of A is not referenced. If UPLO = 'L', the */
+/* leading n-by-n lower triangular part of A contains the lower */
+/* triangular part of the matrix A, and the strictly upper */
+/* triangular part of A is not referenced. */
+
+/* On exit, the block diagonal matrix D and the multipliers used */
+/* to obtain the factor U or L (see below for further details). */
+
+/* LDA (input) INTEGER */
+/* The leading dimension of the array A. LDA >= max(1,N). */
+
+/* IPIV (output) INTEGER array, dimension (N) */
+/* Details of the interchanges and the block structure of D. */
+/* If IPIV(k) > 0, then rows and columns k and IPIV(k) were */
+/* interchanged and D(k,k) is a 1-by-1 diagonal block. */
+/* If UPLO = 'U' and IPIV(k) = IPIV(k-1) < 0, then rows and */
+/* columns k-1 and -IPIV(k) were interchanged and D(k-1:k,k-1:k) */
+/* is a 2-by-2 diagonal block. If UPLO = 'L' and IPIV(k) = */
+/* IPIV(k+1) < 0, then rows and columns k+1 and -IPIV(k) were */
+/* interchanged and D(k:k+1,k:k+1) is a 2-by-2 diagonal block. */
+
+/* INFO (output) INTEGER */
+/* = 0: successful exit */
+/* < 0: if INFO = -k, the k-th argument had an illegal value */
+/* > 0: if INFO = k, D(k,k) is exactly zero. The factorization */
+/* has been completed, but the block diagonal matrix D is */
+/* exactly singular, and division by zero will occur if it */
+/* is used to solve a system of equations. */
+
+/* Further Details */
+/* =============== */
+
+/* 09-29-06 - patch from */
+/* Bobby Cheng, MathWorks */
+
+/* Replace l.209 and l.377 */
+/* IF( MAX( ABSAKK, COLMAX ).EQ.ZERO ) THEN */
+/* by */
+/* IF( (MAX( ABSAKK, COLMAX ).EQ.ZERO) .OR. DISNAN(ABSAKK) ) THEN */
+
+/* 1-96 - Based on modifications by J. Lewis, Boeing Computer Services */
+/* Company */
+
+/* If UPLO = 'U', then A = U*D*U', where */
+/* U = P(n)*U(n)* ... *P(k)U(k)* ..., */
+/* i.e., U is a product of terms P(k)*U(k), where k decreases from n to */
+/* 1 in steps of 1 or 2, and D is a block diagonal matrix with 1-by-1 */
+/* and 2-by-2 diagonal blocks D(k). P(k) is a permutation matrix as */
+/* defined by IPIV(k), and U(k) is a unit upper triangular matrix, such */
+/* that if the diagonal block D(k) is of order s (s = 1 or 2), then */
+
+/* ( I v 0 ) k-s */
+/* U(k) = ( 0 I 0 ) s */
+/* ( 0 0 I ) n-k */
+/* k-s s n-k */
+
+/* If s = 1, D(k) overwrites A(k,k), and v overwrites A(1:k-1,k). */
+/* If s = 2, the upper triangle of D(k) overwrites A(k-1,k-1), A(k-1,k), */
+/* and A(k,k), and v overwrites A(1:k-2,k-1:k). */
+
+/* If UPLO = 'L', then A = L*D*L', where */
+/* L = P(1)*L(1)* ... *P(k)*L(k)* ..., */
+/* i.e., L is a product of terms P(k)*L(k), where k increases from 1 to */
+/* n in steps of 1 or 2, and D is a block diagonal matrix with 1-by-1 */
+/* and 2-by-2 diagonal blocks D(k). P(k) is a permutation matrix as */
+/* defined by IPIV(k), and L(k) is a unit lower triangular matrix, such */
+/* that if the diagonal block D(k) is of order s (s = 1 or 2), then */
+
+/* ( I 0 0 ) k-1 */
+/* L(k) = ( 0 I 0 ) s */
+/* ( 0 v I ) n-k-s+1 */
+/* k-1 s n-k-s+1 */
+
+/* If s = 1, D(k) overwrites A(k,k), and v overwrites A(k+1:n,k). */
+/* If s = 2, the lower triangle of D(k) overwrites A(k,k), A(k+1,k), */
+/* and A(k+1,k+1), and v overwrites A(k+2:n,k:k+1). */
+
+/* ===================================================================== */
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. External Functions .. */
+/* .. */
+/* .. External Subroutines .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Statement Functions .. */
+/* .. */
+/* .. Statement Function definitions .. */
+/* .. */
+/* .. Executable Statements .. */
+
+/* Test the input parameters. */
+
+ /* Parameter adjustments */
+ a_dim1 = *lda;
+ a_offset = 1 + a_dim1;
+ a -= a_offset;
+ --ipiv;
+
+ /* Function Body */
+ *info = 0;
+ upper = lsame_(uplo, "U");
+ if (! upper && ! lsame_(uplo, "L")) {
+ *info = -1;
+ } else if (*n < 0) {
+ *info = -2;
+ } else if (*lda < max(1,*n)) {
+ *info = -4;
+ }
+ if (*info != 0) {
+ i__1 = -(*info);
+ xerbla_("ZSYTF2", &i__1);
+ return 0;
+ }
+
+/* Initialize ALPHA for use in choosing pivot block size. */
+
+ alpha = (sqrt(17.) + 1.) / 8.;
+
+ if (upper) {
+
+/* Factorize A as U*D*U' using the upper triangle of A */
+
+/* K is the main loop index, decreasing from N to 1 in steps of */
+/* 1 or 2 */
+
+ k = *n;
+L10:
+
+/* If K < 1, exit from loop */
+
+ if (k < 1) {
+ goto L70;
+ }
+ kstep = 1;
+
+/* Determine rows and columns to be interchanged and whether */
+/* a 1-by-1 or 2-by-2 pivot block will be used */
+
+ i__1 = k + k * a_dim1;
+ absakk = (d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[k + k *
+ a_dim1]), abs(d__2));
+
+/* IMAX is the row-index of the largest off-diagonal element in */
+/* column K, and COLMAX is its absolute value */
+
+ if (k > 1) {
+ i__1 = k - 1;
+ imax = izamax_(&i__1, &a[k * a_dim1 + 1], &c__1);
+ i__1 = imax + k * a_dim1;
+ colmax = (d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[imax +
+ k * a_dim1]), abs(d__2));
+ } else {
+ colmax = 0.;
+ }
+
+ if (max(absakk,colmax) == 0. || disnan_(&absakk)) {
+
+/* Column K is zero or contains a NaN: set INFO and continue */
+
+ if (*info == 0) {
+ *info = k;
+ }
+ kp = k;
+ } else {
+ if (absakk >= alpha * colmax) {
+
+/* no interchange, use 1-by-1 pivot block */
+
+ kp = k;
+ } else {
+
+/* JMAX is the column-index of the largest off-diagonal */
+/* element in row IMAX, and ROWMAX is its absolute value */
+
+ i__1 = k - imax;
+ jmax = imax + izamax_(&i__1, &a[imax + (imax + 1) * a_dim1],
+ lda);
+ i__1 = imax + jmax * a_dim1;
+ rowmax = (d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[
+ imax + jmax * a_dim1]), abs(d__2));
+ if (imax > 1) {
+ i__1 = imax - 1;
+ jmax = izamax_(&i__1, &a[imax * a_dim1 + 1], &c__1);
+/* Computing MAX */
+ i__1 = jmax + imax * a_dim1;
+ d__3 = rowmax, d__4 = (d__1 = a[i__1].r, abs(d__1)) + (
+ d__2 = d_imag(&a[jmax + imax * a_dim1]), abs(d__2)
+ );
+ rowmax = max(d__3,d__4);
+ }
+
+ if (absakk >= alpha * colmax * (colmax / rowmax)) {
+
+/* no interchange, use 1-by-1 pivot block */
+
+ kp = k;
+ } else /* if(complicated condition) */ {
+ i__1 = imax + imax * a_dim1;
+ if ((d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[
+ imax + imax * a_dim1]), abs(d__2)) >= alpha *
+ rowmax) {
+
+/* interchange rows and columns K and IMAX, use 1-by-1 */
+/* pivot block */
+
+ kp = imax;
+ } else {
+
+/* interchange rows and columns K-1 and IMAX, use 2-by-2 */
+/* pivot block */
+
+ kp = imax;
+ kstep = 2;
+ }
+ }
+ }
+
+ kk = k - kstep + 1;
+ if (kp != kk) {
+
+/* Interchange rows and columns KK and KP in the leading */
+/* submatrix A(1:k,1:k) */
+
+ i__1 = kp - 1;
+ zswap_(&i__1, &a[kk * a_dim1 + 1], &c__1, &a[kp * a_dim1 + 1],
+ &c__1);
+ i__1 = kk - kp - 1;
+ zswap_(&i__1, &a[kp + 1 + kk * a_dim1], &c__1, &a[kp + (kp +
+ 1) * a_dim1], lda);
+ i__1 = kk + kk * a_dim1;
+ t.r = a[i__1].r, t.i = a[i__1].i;
+ i__1 = kk + kk * a_dim1;
+ i__2 = kp + kp * a_dim1;
+ a[i__1].r = a[i__2].r, a[i__1].i = a[i__2].i;
+ i__1 = kp + kp * a_dim1;
+ a[i__1].r = t.r, a[i__1].i = t.i;
+ if (kstep == 2) {
+ i__1 = k - 1 + k * a_dim1;
+ t.r = a[i__1].r, t.i = a[i__1].i;
+ i__1 = k - 1 + k * a_dim1;
+ i__2 = kp + k * a_dim1;
+ a[i__1].r = a[i__2].r, a[i__1].i = a[i__2].i;
+ i__1 = kp + k * a_dim1;
+ a[i__1].r = t.r, a[i__1].i = t.i;
+ }
+ }
+
+/* Update the leading submatrix */
+
+ if (kstep == 1) {
+
+/* 1-by-1 pivot block D(k): column k now holds */
+
+/* W(k) = U(k)*D(k) */
+
+/* where U(k) is the k-th column of U */
+
+/* Perform a rank-1 update of A(1:k-1,1:k-1) as */
+
+/* A := A - U(k)*D(k)*U(k)' = A - W(k)*1/D(k)*W(k)' */
+
+ z_div(&z__1, &c_b1, &a[k + k * a_dim1]);
+ r1.r = z__1.r, r1.i = z__1.i;
+ i__1 = k - 1;
+ z__1.r = -r1.r, z__1.i = -r1.i;
+ zsyr_(uplo, &i__1, &z__1, &a[k * a_dim1 + 1], &c__1, &a[
+ a_offset], lda);
+
+/* Store U(k) in column k */
+
+ i__1 = k - 1;
+ zscal_(&i__1, &r1, &a[k * a_dim1 + 1], &c__1);
+ } else {
+
+/* 2-by-2 pivot block D(k): columns k and k-1 now hold */
+
+/* ( W(k-1) W(k) ) = ( U(k-1) U(k) )*D(k) */
+
+/* where U(k) and U(k-1) are the k-th and (k-1)-th columns */
+/* of U */
+
+/* Perform a rank-2 update of A(1:k-2,1:k-2) as */
+
+/* A := A - ( U(k-1) U(k) )*D(k)*( U(k-1) U(k) )' */
+/* = A - ( W(k-1) W(k) )*inv(D(k))*( W(k-1) W(k) )' */
+
+ if (k > 2) {
+
+ i__1 = k - 1 + k * a_dim1;
+ d12.r = a[i__1].r, d12.i = a[i__1].i;
+ z_div(&z__1, &a[k - 1 + (k - 1) * a_dim1], &d12);
+ d22.r = z__1.r, d22.i = z__1.i;
+ z_div(&z__1, &a[k + k * a_dim1], &d12);
+ d11.r = z__1.r, d11.i = z__1.i;
+ z__3.r = d11.r * d22.r - d11.i * d22.i, z__3.i = d11.r *
+ d22.i + d11.i * d22.r;
+ z__2.r = z__3.r - 1., z__2.i = z__3.i - 0.;
+ z_div(&z__1, &c_b1, &z__2);
+ t.r = z__1.r, t.i = z__1.i;
+ z_div(&z__1, &t, &d12);
+ d12.r = z__1.r, d12.i = z__1.i;
+
+ for (j = k - 2; j >= 1; --j) {
+ i__1 = j + (k - 1) * a_dim1;
+ z__3.r = d11.r * a[i__1].r - d11.i * a[i__1].i,
+ z__3.i = d11.r * a[i__1].i + d11.i * a[i__1]
+ .r;
+ i__2 = j + k * a_dim1;
+ z__2.r = z__3.r - a[i__2].r, z__2.i = z__3.i - a[i__2]
+ .i;
+ z__1.r = d12.r * z__2.r - d12.i * z__2.i, z__1.i =
+ d12.r * z__2.i + d12.i * z__2.r;
+ wkm1.r = z__1.r, wkm1.i = z__1.i;
+ i__1 = j + k * a_dim1;
+ z__3.r = d22.r * a[i__1].r - d22.i * a[i__1].i,
+ z__3.i = d22.r * a[i__1].i + d22.i * a[i__1]
+ .r;
+ i__2 = j + (k - 1) * a_dim1;
+ z__2.r = z__3.r - a[i__2].r, z__2.i = z__3.i - a[i__2]
+ .i;
+ z__1.r = d12.r * z__2.r - d12.i * z__2.i, z__1.i =
+ d12.r * z__2.i + d12.i * z__2.r;
+ wk.r = z__1.r, wk.i = z__1.i;
+ for (i__ = j; i__ >= 1; --i__) {
+ i__1 = i__ + j * a_dim1;
+ i__2 = i__ + j * a_dim1;
+ i__3 = i__ + k * a_dim1;
+ z__3.r = a[i__3].r * wk.r - a[i__3].i * wk.i,
+ z__3.i = a[i__3].r * wk.i + a[i__3].i *
+ wk.r;
+ z__2.r = a[i__2].r - z__3.r, z__2.i = a[i__2].i -
+ z__3.i;
+ i__4 = i__ + (k - 1) * a_dim1;
+ z__4.r = a[i__4].r * wkm1.r - a[i__4].i * wkm1.i,
+ z__4.i = a[i__4].r * wkm1.i + a[i__4].i *
+ wkm1.r;
+ z__1.r = z__2.r - z__4.r, z__1.i = z__2.i -
+ z__4.i;
+ a[i__1].r = z__1.r, a[i__1].i = z__1.i;
+/* L20: */
+ }
+ i__1 = j + k * a_dim1;
+ a[i__1].r = wk.r, a[i__1].i = wk.i;
+ i__1 = j + (k - 1) * a_dim1;
+ a[i__1].r = wkm1.r, a[i__1].i = wkm1.i;
+/* L30: */
+ }
+
+ }
+
+ }
+ }
+
+/* Store details of the interchanges in IPIV */
+
+ if (kstep == 1) {
+ ipiv[k] = kp;
+ } else {
+ ipiv[k] = -kp;
+ ipiv[k - 1] = -kp;
+ }
+
+/* Decrease K and return to the start of the main loop */
+
+ k -= kstep;
+ goto L10;
+
+ } else {
+
+/* Factorize A as L*D*L' using the lower triangle of A */
+
+/* K is the main loop index, increasing from 1 to N in steps of */
+/* 1 or 2 */
+
+ k = 1;
+L40:
+
+/* If K > N, exit from loop */
+
+ if (k > *n) {
+ goto L70;
+ }
+ kstep = 1;
+
+/* Determine rows and columns to be interchanged and whether */
+/* a 1-by-1 or 2-by-2 pivot block will be used */
+
+ i__1 = k + k * a_dim1;
+ absakk = (d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[k + k *
+ a_dim1]), abs(d__2));
+
+/* IMAX is the row-index of the largest off-diagonal element in */
+/* column K, and COLMAX is its absolute value */
+
+ if (k < *n) {
+ i__1 = *n - k;
+ imax = k + izamax_(&i__1, &a[k + 1 + k * a_dim1], &c__1);
+ i__1 = imax + k * a_dim1;
+ colmax = (d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[imax +
+ k * a_dim1]), abs(d__2));
+ } else {
+ colmax = 0.;
+ }
+
+ if (max(absakk,colmax) == 0. || disnan_(&absakk)) {
+
+/* Column K is zero or contains a NaN: set INFO and continue */
+
+ if (*info == 0) {
+ *info = k;
+ }
+ kp = k;
+ } else {
+ if (absakk >= alpha * colmax) {
+
+/* no interchange, use 1-by-1 pivot block */
+
+ kp = k;
+ } else {
+
+/* JMAX is the column-index of the largest off-diagonal */
+/* element in row IMAX, and ROWMAX is its absolute value */
+
+ i__1 = imax - k;
+ jmax = k - 1 + izamax_(&i__1, &a[imax + k * a_dim1], lda);
+ i__1 = imax + jmax * a_dim1;
+ rowmax = (d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[
+ imax + jmax * a_dim1]), abs(d__2));
+ if (imax < *n) {
+ i__1 = *n - imax;
+ jmax = imax + izamax_(&i__1, &a[imax + 1 + imax * a_dim1],
+ &c__1);
+/* Computing MAX */
+ i__1 = jmax + imax * a_dim1;
+ d__3 = rowmax, d__4 = (d__1 = a[i__1].r, abs(d__1)) + (
+ d__2 = d_imag(&a[jmax + imax * a_dim1]), abs(d__2)
+ );
+ rowmax = max(d__3,d__4);
+ }
+
+ if (absakk >= alpha * colmax * (colmax / rowmax)) {
+
+/* no interchange, use 1-by-1 pivot block */
+
+ kp = k;
+ } else /* if(complicated condition) */ {
+ i__1 = imax + imax * a_dim1;
+ if ((d__1 = a[i__1].r, abs(d__1)) + (d__2 = d_imag(&a[
+ imax + imax * a_dim1]), abs(d__2)) >= alpha *
+ rowmax) {
+
+/* interchange rows and columns K and IMAX, use 1-by-1 */
+/* pivot block */
+
+ kp = imax;
+ } else {
+
+/* interchange rows and columns K+1 and IMAX, use 2-by-2 */
+/* pivot block */
+
+ kp = imax;
+ kstep = 2;
+ }
+ }
+ }
+
+ kk = k + kstep - 1;
+ if (kp != kk) {
+
+/* Interchange rows and columns KK and KP in the trailing */
+/* submatrix A(k:n,k:n) */
+
+ if (kp < *n) {
+ i__1 = *n - kp;
+ zswap_(&i__1, &a[kp + 1 + kk * a_dim1], &c__1, &a[kp + 1
+ + kp * a_dim1], &c__1);
+ }
+ i__1 = kp - kk - 1;
+ zswap_(&i__1, &a[kk + 1 + kk * a_dim1], &c__1, &a[kp + (kk +
+ 1) * a_dim1], lda);
+ i__1 = kk + kk * a_dim1;
+ t.r = a[i__1].r, t.i = a[i__1].i;
+ i__1 = kk + kk * a_dim1;
+ i__2 = kp + kp * a_dim1;
+ a[i__1].r = a[i__2].r, a[i__1].i = a[i__2].i;
+ i__1 = kp + kp * a_dim1;
+ a[i__1].r = t.r, a[i__1].i = t.i;
+ if (kstep == 2) {
+ i__1 = k + 1 + k * a_dim1;
+ t.r = a[i__1].r, t.i = a[i__1].i;
+ i__1 = k + 1 + k * a_dim1;
+ i__2 = kp + k * a_dim1;
+ a[i__1].r = a[i__2].r, a[i__1].i = a[i__2].i;
+ i__1 = kp + k * a_dim1;
+ a[i__1].r = t.r, a[i__1].i = t.i;
+ }
+ }
+
+/* Update the trailing submatrix */
+
+ if (kstep == 1) {
+
+/* 1-by-1 pivot block D(k): column k now holds */
+
+/* W(k) = L(k)*D(k) */
+
+/* where L(k) is the k-th column of L */
+
+ if (k < *n) {
+
+/* Perform a rank-1 update of A(k+1:n,k+1:n) as */
+
+/* A := A - L(k)*D(k)*L(k)' = A - W(k)*(1/D(k))*W(k)' */
+
+ z_div(&z__1, &c_b1, &a[k + k * a_dim1]);
+ r1.r = z__1.r, r1.i = z__1.i;
+ i__1 = *n - k;
+ z__1.r = -r1.r, z__1.i = -r1.i;
+ zsyr_(uplo, &i__1, &z__1, &a[k + 1 + k * a_dim1], &c__1, &
+ a[k + 1 + (k + 1) * a_dim1], lda);
+
+/* Store L(k) in column K */
+
+ i__1 = *n - k;
+ zscal_(&i__1, &r1, &a[k + 1 + k * a_dim1], &c__1);
+ }
+ } else {
+
+/* 2-by-2 pivot block D(k) */
+
+ if (k < *n - 1) {
+
+/* Perform a rank-2 update of A(k+2:n,k+2:n) as */
+
+/* A := A - ( L(k) L(k+1) )*D(k)*( L(k) L(k+1) )' */
+/* = A - ( W(k) W(k+1) )*inv(D(k))*( W(k) W(k+1) )' */
+
+/* where L(k) and L(k+1) are the k-th and (k+1)-th */
+/* columns of L */
+
+ i__1 = k + 1 + k * a_dim1;
+ d21.r = a[i__1].r, d21.i = a[i__1].i;
+ z_div(&z__1, &a[k + 1 + (k + 1) * a_dim1], &d21);
+ d11.r = z__1.r, d11.i = z__1.i;
+ z_div(&z__1, &a[k + k * a_dim1], &d21);
+ d22.r = z__1.r, d22.i = z__1.i;
+ z__3.r = d11.r * d22.r - d11.i * d22.i, z__3.i = d11.r *
+ d22.i + d11.i * d22.r;
+ z__2.r = z__3.r - 1., z__2.i = z__3.i - 0.;
+ z_div(&z__1, &c_b1, &z__2);
+ t.r = z__1.r, t.i = z__1.i;
+ z_div(&z__1, &t, &d21);
+ d21.r = z__1.r, d21.i = z__1.i;
+
+ i__1 = *n;
+ for (j = k + 2; j <= i__1; ++j) {
+ i__2 = j + k * a_dim1;
+ z__3.r = d11.r * a[i__2].r - d11.i * a[i__2].i,
+ z__3.i = d11.r * a[i__2].i + d11.i * a[i__2]
+ .r;
+ i__3 = j + (k + 1) * a_dim1;
+ z__2.r = z__3.r - a[i__3].r, z__2.i = z__3.i - a[i__3]
+ .i;
+ z__1.r = d21.r * z__2.r - d21.i * z__2.i, z__1.i =
+ d21.r * z__2.i + d21.i * z__2.r;
+ wk.r = z__1.r, wk.i = z__1.i;
+ i__2 = j + (k + 1) * a_dim1;
+ z__3.r = d22.r * a[i__2].r - d22.i * a[i__2].i,
+ z__3.i = d22.r * a[i__2].i + d22.i * a[i__2]
+ .r;
+ i__3 = j + k * a_dim1;
+ z__2.r = z__3.r - a[i__3].r, z__2.i = z__3.i - a[i__3]
+ .i;
+ z__1.r = d21.r * z__2.r - d21.i * z__2.i, z__1.i =
+ d21.r * z__2.i + d21.i * z__2.r;
+ wkp1.r = z__1.r, wkp1.i = z__1.i;
+ i__2 = *n;
+ for (i__ = j; i__ <= i__2; ++i__) {
+ i__3 = i__ + j * a_dim1;
+ i__4 = i__ + j * a_dim1;
+ i__5 = i__ + k * a_dim1;
+ z__3.r = a[i__5].r * wk.r - a[i__5].i * wk.i,
+ z__3.i = a[i__5].r * wk.i + a[i__5].i *
+ wk.r;
+ z__2.r = a[i__4].r - z__3.r, z__2.i = a[i__4].i -
+ z__3.i;
+ i__6 = i__ + (k + 1) * a_dim1;
+ z__4.r = a[i__6].r * wkp1.r - a[i__6].i * wkp1.i,
+ z__4.i = a[i__6].r * wkp1.i + a[i__6].i *
+ wkp1.r;
+ z__1.r = z__2.r - z__4.r, z__1.i = z__2.i -
+ z__4.i;
+ a[i__3].r = z__1.r, a[i__3].i = z__1.i;
+/* L50: */
+ }
+ i__2 = j + k * a_dim1;
+ a[i__2].r = wk.r, a[i__2].i = wk.i;
+ i__2 = j + (k + 1) * a_dim1;
+ a[i__2].r = wkp1.r, a[i__2].i = wkp1.i;
+/* L60: */
+ }
+ }
+ }
+ }
+
+/* Store details of the interchanges in IPIV */
+
+ if (kstep == 1) {
+ ipiv[k] = kp;
+ } else {
+ ipiv[k] = -kp;
+ ipiv[k + 1] = -kp;
+ }
+
+/* Increase K and return to the start of the main loop */
+
+ k += kstep;
+ goto L40;
+
+ }
+
+L70:
+ return 0;
+
+/* End of ZSYTF2 */
+
+} /* zsytf2_ */