112 lines
3.6 KiB
C++
112 lines
3.6 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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int dlasq6_(integer *i0, integer *n0, doublereal *z__, integer *pp, doublereal *dmin__,
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doublereal *dmin1, doublereal *dmin2, doublereal *dn, doublereal *dnm1,
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doublereal *dnm2)
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{
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integer i__1;
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doublereal d__1, d__2;
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doublereal d__;
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integer j4, j4p2;
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doublereal emin, temp;
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extern doublereal dlamch_(char *, ftnlen);
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doublereal safmin;
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--z__;
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if (*n0 - *i0 - 1 <= 0) {
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return 0;
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}
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safmin = dlamch_((char *)"Safe minimum", (ftnlen)12);
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j4 = (*i0 << 2) + *pp - 3;
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emin = z__[j4 + 4];
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d__ = z__[j4];
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*dmin__ = d__;
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if (*pp == 0) {
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i__1 = *n0 - 3 << 2;
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for (j4 = *i0 << 2; j4 <= i__1; j4 += 4) {
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z__[j4 - 2] = d__ + z__[j4 - 1];
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if (z__[j4 - 2] == 0.) {
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z__[j4] = 0.;
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d__ = z__[j4 + 1];
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*dmin__ = d__;
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emin = 0.;
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} else if (safmin * z__[j4 + 1] < z__[j4 - 2] && safmin * z__[j4 - 2] < z__[j4 + 1]) {
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temp = z__[j4 + 1] / z__[j4 - 2];
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z__[j4] = z__[j4 - 1] * temp;
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d__ *= temp;
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} else {
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z__[j4] = z__[j4 + 1] * (z__[j4 - 1] / z__[j4 - 2]);
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d__ = z__[j4 + 1] * (d__ / z__[j4 - 2]);
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}
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*dmin__ = min(*dmin__, d__);
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d__1 = emin, d__2 = z__[j4];
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emin = min(d__1, d__2);
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}
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} else {
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i__1 = *n0 - 3 << 2;
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for (j4 = *i0 << 2; j4 <= i__1; j4 += 4) {
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z__[j4 - 3] = d__ + z__[j4];
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if (z__[j4 - 3] == 0.) {
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z__[j4 - 1] = 0.;
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d__ = z__[j4 + 2];
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*dmin__ = d__;
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emin = 0.;
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} else if (safmin * z__[j4 + 2] < z__[j4 - 3] && safmin * z__[j4 - 3] < z__[j4 + 2]) {
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temp = z__[j4 + 2] / z__[j4 - 3];
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z__[j4 - 1] = z__[j4] * temp;
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d__ *= temp;
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} else {
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z__[j4 - 1] = z__[j4 + 2] * (z__[j4] / z__[j4 - 3]);
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d__ = z__[j4 + 2] * (d__ / z__[j4 - 3]);
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}
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*dmin__ = min(*dmin__, d__);
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d__1 = emin, d__2 = z__[j4 - 1];
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emin = min(d__1, d__2);
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}
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}
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*dnm2 = d__;
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*dmin2 = *dmin__;
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j4 = (*n0 - 2 << 2) - *pp;
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j4p2 = j4 + (*pp << 1) - 1;
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z__[j4 - 2] = *dnm2 + z__[j4p2];
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if (z__[j4 - 2] == 0.) {
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z__[j4] = 0.;
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*dnm1 = z__[j4p2 + 2];
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*dmin__ = *dnm1;
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emin = 0.;
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} else if (safmin * z__[j4p2 + 2] < z__[j4 - 2] && safmin * z__[j4 - 2] < z__[j4p2 + 2]) {
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temp = z__[j4p2 + 2] / z__[j4 - 2];
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z__[j4] = z__[j4p2] * temp;
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*dnm1 = *dnm2 * temp;
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} else {
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z__[j4] = z__[j4p2 + 2] * (z__[j4p2] / z__[j4 - 2]);
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*dnm1 = z__[j4p2 + 2] * (*dnm2 / z__[j4 - 2]);
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}
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*dmin__ = min(*dmin__, *dnm1);
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*dmin1 = *dmin__;
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j4 += 4;
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j4p2 = j4 + (*pp << 1) - 1;
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z__[j4 - 2] = *dnm1 + z__[j4p2];
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if (z__[j4 - 2] == 0.) {
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z__[j4] = 0.;
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*dn = z__[j4p2 + 2];
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*dmin__ = *dn;
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emin = 0.;
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} else if (safmin * z__[j4p2 + 2] < z__[j4 - 2] && safmin * z__[j4 - 2] < z__[j4p2 + 2]) {
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temp = z__[j4p2 + 2] / z__[j4 - 2];
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z__[j4] = z__[j4p2] * temp;
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*dn = *dnm1 * temp;
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} else {
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z__[j4] = z__[j4p2 + 2] * (z__[j4p2] / z__[j4 - 2]);
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*dn = z__[j4p2 + 2] * (*dnm1 / z__[j4 - 2]);
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}
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*dmin__ = min(*dmin__, *dn);
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z__[j4 + 2] = *dn;
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z__[(*n0 << 2) - *pp] = emin;
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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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