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lammps-gran-kokkos/lib/linalg/dlahqr.cpp
2024-11-09 04:14:11 -05:00

312 lines
11 KiB
C++

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
static integer c__1 = 1;
int dlahqr_(logical *wantt, logical *wantz, integer *n, integer *ilo, integer *ihi, doublereal *h__,
integer *ldh, doublereal *wr, doublereal *wi, integer *iloz, integer *ihiz,
doublereal *z__, integer *ldz, integer *info)
{
integer h_dim1, h_offset, z_dim1, z_offset, i__1, i__2, i__3, i__4;
doublereal d__1, d__2, d__3, d__4;
double sqrt(doublereal);
integer i__, j, k, l, m;
doublereal s, v[3];
integer i1, i2;
doublereal t1, t2, t3, v2, v3, aa, ab, ba, bb, h11, h12, h21, h22, cs;
integer nh;
doublereal sn;
integer nr;
doublereal tr;
integer nz;
doublereal det, h21s;
integer its;
doublereal ulp, sum, tst, rt1i, rt2i, rt1r, rt2r;
extern int drot_(integer *, doublereal *, integer *, doublereal *, integer *, doublereal *,
doublereal *),
dcopy_(integer *, doublereal *, integer *, doublereal *, integer *);
integer itmax;
extern int dlanv2_(doublereal *, doublereal *, doublereal *, doublereal *, doublereal *,
doublereal *, doublereal *, doublereal *, doublereal *, doublereal *),
dlabad_(doublereal *, doublereal *);
extern doublereal dlamch_(char *, ftnlen);
extern int dlarfg_(integer *, doublereal *, doublereal *, integer *, doublereal *);
doublereal safmin, safmax, rtdisc, smlnum;
h_dim1 = *ldh;
h_offset = 1 + h_dim1;
h__ -= h_offset;
--wr;
--wi;
z_dim1 = *ldz;
z_offset = 1 + z_dim1;
z__ -= z_offset;
*info = 0;
if (*n == 0) {
return 0;
}
if (*ilo == *ihi) {
wr[*ilo] = h__[*ilo + *ilo * h_dim1];
wi[*ilo] = 0.;
return 0;
}
i__1 = *ihi - 3;
for (j = *ilo; j <= i__1; ++j) {
h__[j + 2 + j * h_dim1] = 0.;
h__[j + 3 + j * h_dim1] = 0.;
}
if (*ilo <= *ihi - 2) {
h__[*ihi + (*ihi - 2) * h_dim1] = 0.;
}
nh = *ihi - *ilo + 1;
nz = *ihiz - *iloz + 1;
safmin = dlamch_((char *)"SAFE MINIMUM", (ftnlen)12);
safmax = 1. / safmin;
dlabad_(&safmin, &safmax);
ulp = dlamch_((char *)"PRECISION", (ftnlen)9);
smlnum = safmin * ((doublereal)nh / ulp);
if (*wantt) {
i1 = 1;
i2 = *n;
}
itmax = max(10, nh) * 30;
i__ = *ihi;
L20:
l = *ilo;
if (i__ < *ilo) {
goto L160;
}
i__1 = itmax;
for (its = 0; its <= i__1; ++its) {
i__2 = l + 1;
for (k = i__; k >= i__2; --k) {
if ((d__1 = h__[k + (k - 1) * h_dim1], abs(d__1)) <= smlnum) {
goto L40;
}
tst = (d__1 = h__[k - 1 + (k - 1) * h_dim1], abs(d__1)) +
(d__2 = h__[k + k * h_dim1], abs(d__2));
if (tst == 0.) {
if (k - 2 >= *ilo) {
tst += (d__1 = h__[k - 1 + (k - 2) * h_dim1], abs(d__1));
}
if (k + 1 <= *ihi) {
tst += (d__1 = h__[k + 1 + k * h_dim1], abs(d__1));
}
}
if ((d__1 = h__[k + (k - 1) * h_dim1], abs(d__1)) <= ulp * tst) {
d__3 = (d__1 = h__[k + (k - 1) * h_dim1], abs(d__1)),
d__4 = (d__2 = h__[k - 1 + k * h_dim1], abs(d__2));
ab = max(d__3, d__4);
d__3 = (d__1 = h__[k + (k - 1) * h_dim1], abs(d__1)),
d__4 = (d__2 = h__[k - 1 + k * h_dim1], abs(d__2));
ba = min(d__3, d__4);
d__3 = (d__1 = h__[k + k * h_dim1], abs(d__1)),
d__4 = (d__2 = h__[k - 1 + (k - 1) * h_dim1] - h__[k + k * h_dim1], abs(d__2));
aa = max(d__3, d__4);
d__3 = (d__1 = h__[k + k * h_dim1], abs(d__1)),
d__4 = (d__2 = h__[k - 1 + (k - 1) * h_dim1] - h__[k + k * h_dim1], abs(d__2));
bb = min(d__3, d__4);
s = aa + ab;
d__1 = smlnum, d__2 = ulp * (bb * (aa / s));
if (ba * (ab / s) <= max(d__1, d__2)) {
goto L40;
}
}
}
L40:
l = k;
if (l > *ilo) {
h__[l + (l - 1) * h_dim1] = 0.;
}
if (l >= i__ - 1) {
goto L150;
}
if (!(*wantt)) {
i1 = l;
i2 = i__;
}
if (its == 10) {
s = (d__1 = h__[l + 1 + l * h_dim1], abs(d__1)) +
(d__2 = h__[l + 2 + (l + 1) * h_dim1], abs(d__2));
h11 = s * .75 + h__[l + l * h_dim1];
h12 = s * -.4375;
h21 = s;
h22 = h11;
} else if (its == 20) {
s = (d__1 = h__[i__ + (i__ - 1) * h_dim1], abs(d__1)) +
(d__2 = h__[i__ - 1 + (i__ - 2) * h_dim1], abs(d__2));
h11 = s * .75 + h__[i__ + i__ * h_dim1];
h12 = s * -.4375;
h21 = s;
h22 = h11;
} else {
h11 = h__[i__ - 1 + (i__ - 1) * h_dim1];
h21 = h__[i__ + (i__ - 1) * h_dim1];
h12 = h__[i__ - 1 + i__ * h_dim1];
h22 = h__[i__ + i__ * h_dim1];
}
s = abs(h11) + abs(h12) + abs(h21) + abs(h22);
if (s == 0.) {
rt1r = 0.;
rt1i = 0.;
rt2r = 0.;
rt2i = 0.;
} else {
h11 /= s;
h21 /= s;
h12 /= s;
h22 /= s;
tr = (h11 + h22) / 2.;
det = (h11 - tr) * (h22 - tr) - h12 * h21;
rtdisc = sqrt((abs(det)));
if (det >= 0.) {
rt1r = tr * s;
rt2r = rt1r;
rt1i = rtdisc * s;
rt2i = -rt1i;
} else {
rt1r = tr + rtdisc;
rt2r = tr - rtdisc;
if ((d__1 = rt1r - h22, abs(d__1)) <= (d__2 = rt2r - h22, abs(d__2))) {
rt1r *= s;
rt2r = rt1r;
} else {
rt2r *= s;
rt1r = rt2r;
}
rt1i = 0.;
rt2i = 0.;
}
}
i__2 = l;
for (m = i__ - 2; m >= i__2; --m) {
h21s = h__[m + 1 + m * h_dim1];
s = (d__1 = h__[m + m * h_dim1] - rt2r, abs(d__1)) + abs(rt2i) + abs(h21s);
h21s = h__[m + 1 + m * h_dim1] / s;
v[0] = h21s * h__[m + (m + 1) * h_dim1] +
(h__[m + m * h_dim1] - rt1r) * ((h__[m + m * h_dim1] - rt2r) / s) -
rt1i * (rt2i / s);
v[1] = h21s * (h__[m + m * h_dim1] + h__[m + 1 + (m + 1) * h_dim1] - rt1r - rt2r);
v[2] = h21s * h__[m + 2 + (m + 1) * h_dim1];
s = abs(v[0]) + abs(v[1]) + abs(v[2]);
v[0] /= s;
v[1] /= s;
v[2] /= s;
if (m == l) {
goto L60;
}
if ((d__1 = h__[m + (m - 1) * h_dim1], abs(d__1)) * (abs(v[1]) + abs(v[2])) <=
ulp * abs(v[0]) *
((d__2 = h__[m - 1 + (m - 1) * h_dim1], abs(d__2)) +
(d__3 = h__[m + m * h_dim1], abs(d__3)) +
(d__4 = h__[m + 1 + (m + 1) * h_dim1], abs(d__4)))) {
goto L60;
}
}
L60:
i__2 = i__ - 1;
for (k = m; k <= i__2; ++k) {
i__3 = 3, i__4 = i__ - k + 1;
nr = min(i__3, i__4);
if (k > m) {
dcopy_(&nr, &h__[k + (k - 1) * h_dim1], &c__1, v, &c__1);
}
dlarfg_(&nr, v, &v[1], &c__1, &t1);
if (k > m) {
h__[k + (k - 1) * h_dim1] = v[0];
h__[k + 1 + (k - 1) * h_dim1] = 0.;
if (k < i__ - 1) {
h__[k + 2 + (k - 1) * h_dim1] = 0.;
}
} else if (m > l) {
h__[k + (k - 1) * h_dim1] *= 1. - t1;
}
v2 = v[1];
t2 = t1 * v2;
if (nr == 3) {
v3 = v[2];
t3 = t1 * v3;
i__3 = i2;
for (j = k; j <= i__3; ++j) {
sum = h__[k + j * h_dim1] + v2 * h__[k + 1 + j * h_dim1] +
v3 * h__[k + 2 + j * h_dim1];
h__[k + j * h_dim1] -= sum * t1;
h__[k + 1 + j * h_dim1] -= sum * t2;
h__[k + 2 + j * h_dim1] -= sum * t3;
}
i__4 = k + 3;
i__3 = min(i__4, i__);
for (j = i1; j <= i__3; ++j) {
sum = h__[j + k * h_dim1] + v2 * h__[j + (k + 1) * h_dim1] +
v3 * h__[j + (k + 2) * h_dim1];
h__[j + k * h_dim1] -= sum * t1;
h__[j + (k + 1) * h_dim1] -= sum * t2;
h__[j + (k + 2) * h_dim1] -= sum * t3;
}
if (*wantz) {
i__3 = *ihiz;
for (j = *iloz; j <= i__3; ++j) {
sum = z__[j + k * z_dim1] + v2 * z__[j + (k + 1) * z_dim1] +
v3 * z__[j + (k + 2) * z_dim1];
z__[j + k * z_dim1] -= sum * t1;
z__[j + (k + 1) * z_dim1] -= sum * t2;
z__[j + (k + 2) * z_dim1] -= sum * t3;
}
}
} else if (nr == 2) {
i__3 = i2;
for (j = k; j <= i__3; ++j) {
sum = h__[k + j * h_dim1] + v2 * h__[k + 1 + j * h_dim1];
h__[k + j * h_dim1] -= sum * t1;
h__[k + 1 + j * h_dim1] -= sum * t2;
}
i__3 = i__;
for (j = i1; j <= i__3; ++j) {
sum = h__[j + k * h_dim1] + v2 * h__[j + (k + 1) * h_dim1];
h__[j + k * h_dim1] -= sum * t1;
h__[j + (k + 1) * h_dim1] -= sum * t2;
}
if (*wantz) {
i__3 = *ihiz;
for (j = *iloz; j <= i__3; ++j) {
sum = z__[j + k * z_dim1] + v2 * z__[j + (k + 1) * z_dim1];
z__[j + k * z_dim1] -= sum * t1;
z__[j + (k + 1) * z_dim1] -= sum * t2;
}
}
}
}
}
*info = i__;
return 0;
L150:
if (l == i__) {
wr[i__] = h__[i__ + i__ * h_dim1];
wi[i__] = 0.;
} else if (l == i__ - 1) {
dlanv2_(&h__[i__ - 1 + (i__ - 1) * h_dim1], &h__[i__ - 1 + i__ * h_dim1],
&h__[i__ + (i__ - 1) * h_dim1], &h__[i__ + i__ * h_dim1], &wr[i__ - 1],
&wi[i__ - 1], &wr[i__], &wi[i__], &cs, &sn);
if (*wantt) {
if (i2 > i__) {
i__1 = i2 - i__;
drot_(&i__1, &h__[i__ - 1 + (i__ + 1) * h_dim1], ldh,
&h__[i__ + (i__ + 1) * h_dim1], ldh, &cs, &sn);
}
i__1 = i__ - i1 - 1;
drot_(&i__1, &h__[i1 + (i__ - 1) * h_dim1], &c__1, &h__[i1 + i__ * h_dim1], &c__1, &cs,
&sn);
}
if (*wantz) {
drot_(&nz, &z__[*iloz + (i__ - 1) * z_dim1], &c__1, &z__[*iloz + i__ * z_dim1], &c__1,
&cs, &sn);
}
}
i__ = l - 1;
goto L20;
L160:
return 0;
}
#ifdef __cplusplus
}
#endif