54 lines
1.5 KiB
C++
54 lines
1.5 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 dlas2_(doublereal *f, doublereal *g, doublereal *h__, doublereal *ssmin, doublereal *ssmax)
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{
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doublereal d__1, d__2;
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double sqrt(doublereal);
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doublereal c__, fa, ga, ha, as, at, au, fhmn, fhmx;
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fa = abs(*f);
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ga = abs(*g);
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ha = abs(*h__);
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fhmn = min(fa, ha);
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fhmx = max(fa, ha);
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if (fhmn == 0.) {
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*ssmin = 0.;
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if (fhmx == 0.) {
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*ssmax = ga;
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} else {
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d__1 = min(fhmx, ga) / max(fhmx, ga);
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*ssmax = max(fhmx, ga) * sqrt(d__1 * d__1 + 1.);
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}
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} else {
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if (ga < fhmx) {
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as = fhmn / fhmx + 1.;
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at = (fhmx - fhmn) / fhmx;
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d__1 = ga / fhmx;
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au = d__1 * d__1;
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c__ = 2. / (sqrt(as * as + au) + sqrt(at * at + au));
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*ssmin = fhmn * c__;
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*ssmax = fhmx / c__;
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} else {
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au = fhmx / ga;
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if (au == 0.) {
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*ssmin = fhmn * fhmx / ga;
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*ssmax = ga;
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} else {
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as = fhmn / fhmx + 1.;
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at = (fhmx - fhmn) / fhmx;
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d__1 = as * au;
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d__2 = at * au;
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c__ = 1. / (sqrt(d__1 * d__1 + 1.) + sqrt(d__2 * d__2 + 1.));
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*ssmin = fhmn * c__ * au;
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*ssmin += *ssmin;
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*ssmax = ga / (c__ + c__);
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}
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}
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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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