287 lines
7.6 KiB
C++
287 lines
7.6 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 integer c__0 = 0;
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static integer c__1 = 1;
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static doublereal c_b33 = 1.;
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int dsterf_(integer *n, doublereal *d__, doublereal *e, integer *info)
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{
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integer i__1;
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doublereal d__1, d__2, d__3;
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double sqrt(doublereal), d_lmp_sign(doublereal *, doublereal *);
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doublereal c__;
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integer i__, l, m;
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doublereal p, r__, s;
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integer l1;
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doublereal bb, rt1, rt2, eps, rte;
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integer lsv;
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doublereal eps2, oldc;
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integer lend;
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doublereal rmax;
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integer jtot;
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extern int dlae2_(doublereal *, doublereal *, doublereal *, doublereal *, doublereal *);
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doublereal gamma, alpha, sigma, anorm;
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extern doublereal dlapy2_(doublereal *, doublereal *), dlamch_(char *, ftnlen);
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integer iscale;
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extern int dlascl_(char *, integer *, integer *, doublereal *, doublereal *, integer *,
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integer *, doublereal *, integer *, integer *, ftnlen);
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doublereal oldgam, safmin;
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extern int xerbla_(char *, integer *, ftnlen);
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doublereal safmax;
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extern doublereal dlanst_(char *, integer *, doublereal *, doublereal *, ftnlen);
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extern int dlasrt_(char *, integer *, doublereal *, integer *, ftnlen);
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integer lendsv;
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doublereal ssfmin;
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integer nmaxit;
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doublereal ssfmax;
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--e;
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--d__;
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*info = 0;
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if (*n < 0) {
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*info = -1;
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i__1 = -(*info);
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xerbla_((char *)"DSTERF", &i__1, (ftnlen)6);
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return 0;
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}
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if (*n <= 1) {
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return 0;
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}
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eps = dlamch_((char *)"E", (ftnlen)1);
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d__1 = eps;
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eps2 = d__1 * d__1;
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safmin = dlamch_((char *)"S", (ftnlen)1);
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safmax = 1. / safmin;
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ssfmax = sqrt(safmax) / 3.;
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ssfmin = sqrt(safmin) / eps2;
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rmax = dlamch_((char *)"O", (ftnlen)1);
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nmaxit = *n * 30;
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sigma = 0.;
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jtot = 0;
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l1 = 1;
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L10:
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if (l1 > *n) {
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goto L170;
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}
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if (l1 > 1) {
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e[l1 - 1] = 0.;
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}
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i__1 = *n - 1;
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for (m = l1; m <= i__1; ++m) {
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if ((d__3 = e[m], abs(d__3)) <=
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sqrt((d__1 = d__[m], abs(d__1))) * sqrt((d__2 = d__[m + 1], abs(d__2))) * eps) {
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e[m] = 0.;
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goto L30;
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}
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}
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m = *n;
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L30:
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l = l1;
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lsv = l;
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lend = m;
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lendsv = lend;
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l1 = m + 1;
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if (lend == l) {
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goto L10;
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}
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i__1 = lend - l + 1;
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anorm = dlanst_((char *)"M", &i__1, &d__[l], &e[l], (ftnlen)1);
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iscale = 0;
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if (anorm == 0.) {
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goto L10;
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}
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if (anorm > ssfmax) {
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iscale = 1;
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i__1 = lend - l + 1;
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dlascl_((char *)"G", &c__0, &c__0, &anorm, &ssfmax, &i__1, &c__1, &d__[l], n, info, (ftnlen)1);
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i__1 = lend - l;
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dlascl_((char *)"G", &c__0, &c__0, &anorm, &ssfmax, &i__1, &c__1, &e[l], n, info, (ftnlen)1);
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} else if (anorm < ssfmin) {
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iscale = 2;
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i__1 = lend - l + 1;
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dlascl_((char *)"G", &c__0, &c__0, &anorm, &ssfmin, &i__1, &c__1, &d__[l], n, info, (ftnlen)1);
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i__1 = lend - l;
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dlascl_((char *)"G", &c__0, &c__0, &anorm, &ssfmin, &i__1, &c__1, &e[l], n, info, (ftnlen)1);
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}
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i__1 = lend - 1;
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for (i__ = l; i__ <= i__1; ++i__) {
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d__1 = e[i__];
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e[i__] = d__1 * d__1;
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}
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if ((d__1 = d__[lend], abs(d__1)) < (d__2 = d__[l], abs(d__2))) {
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lend = lsv;
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l = lendsv;
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}
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if (lend >= l) {
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L50:
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if (l != lend) {
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i__1 = lend - 1;
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for (m = l; m <= i__1; ++m) {
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if ((d__2 = e[m], abs(d__2)) <= eps2 * (d__1 = d__[m] * d__[m + 1], abs(d__1))) {
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goto L70;
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}
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}
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}
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m = lend;
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L70:
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if (m < lend) {
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e[m] = 0.;
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}
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p = d__[l];
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if (m == l) {
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goto L90;
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}
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if (m == l + 1) {
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rte = sqrt(e[l]);
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dlae2_(&d__[l], &rte, &d__[l + 1], &rt1, &rt2);
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d__[l] = rt1;
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d__[l + 1] = rt2;
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e[l] = 0.;
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l += 2;
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if (l <= lend) {
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goto L50;
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}
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goto L150;
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}
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if (jtot == nmaxit) {
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goto L150;
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}
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++jtot;
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rte = sqrt(e[l]);
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sigma = (d__[l + 1] - p) / (rte * 2.);
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r__ = dlapy2_(&sigma, &c_b33);
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sigma = p - rte / (sigma + d_lmp_sign(&r__, &sigma));
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c__ = 1.;
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s = 0.;
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gamma = d__[m] - sigma;
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p = gamma * gamma;
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i__1 = l;
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for (i__ = m - 1; i__ >= i__1; --i__) {
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bb = e[i__];
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r__ = p + bb;
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if (i__ != m - 1) {
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e[i__ + 1] = s * r__;
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}
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oldc = c__;
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c__ = p / r__;
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s = bb / r__;
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oldgam = gamma;
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alpha = d__[i__];
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gamma = c__ * (alpha - sigma) - s * oldgam;
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d__[i__ + 1] = oldgam + (alpha - gamma);
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if (c__ != 0.) {
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p = gamma * gamma / c__;
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} else {
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p = oldc * bb;
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}
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}
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e[l] = s * p;
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d__[l] = sigma + gamma;
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goto L50;
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L90:
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d__[l] = p;
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++l;
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if (l <= lend) {
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goto L50;
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}
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goto L150;
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} else {
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L100:
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i__1 = lend + 1;
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for (m = l; m >= i__1; --m) {
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if ((d__2 = e[m - 1], abs(d__2)) <= eps2 * (d__1 = d__[m] * d__[m - 1], abs(d__1))) {
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goto L120;
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}
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}
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m = lend;
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L120:
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if (m > lend) {
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e[m - 1] = 0.;
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}
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p = d__[l];
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if (m == l) {
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goto L140;
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}
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if (m == l - 1) {
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rte = sqrt(e[l - 1]);
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dlae2_(&d__[l], &rte, &d__[l - 1], &rt1, &rt2);
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d__[l] = rt1;
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d__[l - 1] = rt2;
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e[l - 1] = 0.;
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l += -2;
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if (l >= lend) {
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goto L100;
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}
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goto L150;
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}
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if (jtot == nmaxit) {
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goto L150;
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}
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++jtot;
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rte = sqrt(e[l - 1]);
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sigma = (d__[l - 1] - p) / (rte * 2.);
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r__ = dlapy2_(&sigma, &c_b33);
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sigma = p - rte / (sigma + d_lmp_sign(&r__, &sigma));
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c__ = 1.;
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s = 0.;
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gamma = d__[m] - sigma;
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p = gamma * gamma;
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i__1 = l - 1;
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for (i__ = m; i__ <= i__1; ++i__) {
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bb = e[i__];
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r__ = p + bb;
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if (i__ != m) {
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e[i__ - 1] = s * r__;
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}
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oldc = c__;
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c__ = p / r__;
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s = bb / r__;
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oldgam = gamma;
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alpha = d__[i__ + 1];
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gamma = c__ * (alpha - sigma) - s * oldgam;
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d__[i__] = oldgam + (alpha - gamma);
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if (c__ != 0.) {
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p = gamma * gamma / c__;
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} else {
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p = oldc * bb;
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}
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}
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e[l - 1] = s * p;
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d__[l] = sigma + gamma;
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goto L100;
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L140:
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d__[l] = p;
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--l;
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if (l >= lend) {
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goto L100;
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}
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goto L150;
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}
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L150:
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if (iscale == 1) {
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i__1 = lendsv - lsv + 1;
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dlascl_((char *)"G", &c__0, &c__0, &ssfmax, &anorm, &i__1, &c__1, &d__[lsv], n, info, (ftnlen)1);
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}
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if (iscale == 2) {
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i__1 = lendsv - lsv + 1;
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dlascl_((char *)"G", &c__0, &c__0, &ssfmin, &anorm, &i__1, &c__1, &d__[lsv], n, info, (ftnlen)1);
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}
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if (jtot < nmaxit) {
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goto L10;
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}
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i__1 = *n - 1;
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for (i__ = 1; i__ <= i__1; ++i__) {
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if (e[i__] != 0.) {
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++(*info);
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}
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}
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goto L180;
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L170:
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dlasrt_((char *)"I", n, &d__[1], info, (ftnlen)1);
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L180:
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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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