207 lines
6.1 KiB
C++
207 lines
6.1 KiB
C++
#ifdef __cplusplus
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extern "C" {
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#endif
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#include "lmp_f2c.h"
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static doublereal c_b3 = -1.;
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static integer c__1 = 1;
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int zlaed8_(integer *k, integer *n, integer *qsiz, doublecomplex *q, integer *ldq, doublereal *d__,
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doublereal *rho, integer *cutpnt, doublereal *z__, doublereal *dlambda,
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doublecomplex *q2, integer *ldq2, doublereal *w, integer *indxp, integer *indx,
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integer *indxq, integer *perm, integer *givptr, integer *givcol, doublereal *givnum,
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integer *info)
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{
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integer q_dim1, q_offset, q2_dim1, q2_offset, i__1;
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doublereal d__1;
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double sqrt(doublereal);
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doublereal c__;
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integer i__, j;
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doublereal s, t;
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integer k2, n1, n2, jp, n1p1;
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doublereal eps, tau, tol;
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integer jlam, imax, jmax;
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extern int dscal_(integer *, doublereal *, doublereal *, integer *),
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dcopy_(integer *, doublereal *, integer *, doublereal *, integer *),
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zdrot_(integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublereal *,
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doublereal *),
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zcopy_(integer *, doublecomplex *, integer *, doublecomplex *, integer *);
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extern doublereal dlapy2_(doublereal *, doublereal *), dlamch_(char *, ftnlen);
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extern integer idamax_(integer *, doublereal *, integer *);
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extern int dlamrg_(integer *, integer *, doublereal *, integer *, integer *, integer *),
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xerbla_(char *, integer *, ftnlen),
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zlacpy_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *,
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integer *, ftnlen);
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q_dim1 = *ldq;
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q_offset = 1 + q_dim1;
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q -= q_offset;
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--d__;
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--z__;
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--dlambda;
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q2_dim1 = *ldq2;
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q2_offset = 1 + q2_dim1;
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q2 -= q2_offset;
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--w;
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--indxp;
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--indx;
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--indxq;
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--perm;
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givcol -= 3;
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givnum -= 3;
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*info = 0;
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if (*n < 0) {
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*info = -2;
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} else if (*qsiz < *n) {
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*info = -3;
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} else if (*ldq < max(1, *n)) {
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*info = -5;
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} else if (*cutpnt < min(1, *n) || *cutpnt > *n) {
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*info = -8;
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} else if (*ldq2 < max(1, *n)) {
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*info = -12;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_((char *)"ZLAED8", &i__1, (ftnlen)6);
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return 0;
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}
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*givptr = 0;
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if (*n == 0) {
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return 0;
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}
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n1 = *cutpnt;
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n2 = *n - n1;
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n1p1 = n1 + 1;
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if (*rho < 0.) {
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dscal_(&n2, &c_b3, &z__[n1p1], &c__1);
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}
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t = 1. / sqrt(2.);
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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indx[j] = j;
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}
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dscal_(n, &t, &z__[1], &c__1);
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*rho = (d__1 = *rho * 2., abs(d__1));
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i__1 = *n;
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for (i__ = *cutpnt + 1; i__ <= i__1; ++i__) {
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indxq[i__] += *cutpnt;
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}
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i__1 = *n;
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for (i__ = 1; i__ <= i__1; ++i__) {
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dlambda[i__] = d__[indxq[i__]];
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w[i__] = z__[indxq[i__]];
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}
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i__ = 1;
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j = *cutpnt + 1;
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dlamrg_(&n1, &n2, &dlambda[1], &c__1, &c__1, &indx[1]);
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i__1 = *n;
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for (i__ = 1; i__ <= i__1; ++i__) {
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d__[i__] = dlambda[indx[i__]];
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z__[i__] = w[indx[i__]];
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}
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imax = idamax_(n, &z__[1], &c__1);
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jmax = idamax_(n, &d__[1], &c__1);
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eps = dlamch_((char *)"Epsilon", (ftnlen)7);
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tol = eps * 8. * (d__1 = d__[jmax], abs(d__1));
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if (*rho * (d__1 = z__[imax], abs(d__1)) <= tol) {
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*k = 0;
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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perm[j] = indxq[indx[j]];
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zcopy_(qsiz, &q[perm[j] * q_dim1 + 1], &c__1, &q2[j * q2_dim1 + 1], &c__1);
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}
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zlacpy_((char *)"A", qsiz, n, &q2[q2_dim1 + 1], ldq2, &q[q_dim1 + 1], ldq, (ftnlen)1);
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return 0;
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}
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*k = 0;
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k2 = *n + 1;
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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if (*rho * (d__1 = z__[j], abs(d__1)) <= tol) {
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--k2;
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indxp[k2] = j;
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if (j == *n) {
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goto L100;
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}
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} else {
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jlam = j;
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goto L70;
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}
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}
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L70:
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++j;
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if (j > *n) {
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goto L90;
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}
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if (*rho * (d__1 = z__[j], abs(d__1)) <= tol) {
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--k2;
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indxp[k2] = j;
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} else {
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s = z__[jlam];
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c__ = z__[j];
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tau = dlapy2_(&c__, &s);
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t = d__[j] - d__[jlam];
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c__ /= tau;
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s = -s / tau;
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if ((d__1 = t * c__ * s, abs(d__1)) <= tol) {
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z__[j] = tau;
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z__[jlam] = 0.;
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++(*givptr);
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givcol[(*givptr << 1) + 1] = indxq[indx[jlam]];
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givcol[(*givptr << 1) + 2] = indxq[indx[j]];
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givnum[(*givptr << 1) + 1] = c__;
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givnum[(*givptr << 1) + 2] = s;
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zdrot_(qsiz, &q[indxq[indx[jlam]] * q_dim1 + 1], &c__1, &q[indxq[indx[j]] * q_dim1 + 1],
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&c__1, &c__, &s);
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t = d__[jlam] * c__ * c__ + d__[j] * s * s;
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d__[j] = d__[jlam] * s * s + d__[j] * c__ * c__;
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d__[jlam] = t;
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--k2;
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i__ = 1;
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L80:
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if (k2 + i__ <= *n) {
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if (d__[jlam] < d__[indxp[k2 + i__]]) {
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indxp[k2 + i__ - 1] = indxp[k2 + i__];
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indxp[k2 + i__] = jlam;
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++i__;
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goto L80;
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} else {
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indxp[k2 + i__ - 1] = jlam;
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}
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} else {
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indxp[k2 + i__ - 1] = jlam;
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}
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jlam = j;
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} else {
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++(*k);
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w[*k] = z__[jlam];
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dlambda[*k] = d__[jlam];
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indxp[*k] = jlam;
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jlam = j;
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}
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}
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goto L70;
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L90:
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++(*k);
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w[*k] = z__[jlam];
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dlambda[*k] = d__[jlam];
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indxp[*k] = jlam;
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L100:
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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jp = indxp[j];
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dlambda[j] = d__[jp];
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perm[j] = indxq[indx[jp]];
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zcopy_(qsiz, &q[perm[j] * q_dim1 + 1], &c__1, &q2[j * q2_dim1 + 1], &c__1);
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}
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if (*k < *n) {
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i__1 = *n - *k;
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dcopy_(&i__1, &dlambda[*k + 1], &c__1, &d__[*k + 1], &c__1);
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i__1 = *n - *k;
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zlacpy_((char *)"A", qsiz, &i__1, &q2[(*k + 1) * q2_dim1 + 1], ldq2, &q[(*k + 1) * q_dim1 + 1], ldq,
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(ftnlen)1);
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}
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return 0;
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}
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#ifdef __cplusplus
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}
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#endif
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