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lammps/lib/linalg/dstedc.cpp

239 lines
8.5 KiB
C++

#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
static integer c__9 = 9;
static integer c__0 = 0;
static integer c__2 = 2;
static doublereal c_b17 = 0.;
static doublereal c_b18 = 1.;
static integer c__1 = 1;
int dstedc_(char *compz, integer *n, doublereal *d__, doublereal *e, doublereal *z__, integer *ldz,
doublereal *work, integer *lwork, integer *iwork, integer *liwork, integer *info,
ftnlen compz_len)
{
integer z_dim1, z_offset, i__1, i__2;
doublereal d__1, d__2;
double log(doublereal);
integer pow_lmp_ii(integer *, integer *);
double sqrt(doublereal);
integer i__, j, k, m;
doublereal p;
integer ii, lgn;
doublereal eps, tiny;
extern int dgemm_(char *, char *, integer *, integer *, integer *, doublereal *, doublereal *,
integer *, doublereal *, integer *, doublereal *, doublereal *, integer *,
ftnlen, ftnlen);
extern logical lsame_(char *, char *, ftnlen, ftnlen);
extern int dswap_(integer *, doublereal *, integer *, doublereal *, integer *);
integer lwmin;
extern int dlaed0_(integer *, integer *, integer *, doublereal *, doublereal *, doublereal *,
integer *, doublereal *, integer *, doublereal *, integer *, integer *);
integer start;
extern doublereal dlamch_(char *, ftnlen);
extern int dlascl_(char *, integer *, integer *, doublereal *, doublereal *, integer *,
integer *, doublereal *, integer *, integer *, ftnlen),
dlacpy_(char *, integer *, integer *, doublereal *, integer *, doublereal *, integer *,
ftnlen),
dlaset_(char *, integer *, integer *, doublereal *, doublereal *, doublereal *, integer *,
ftnlen);
extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *,
ftnlen, ftnlen);
extern int xerbla_(char *, integer *, ftnlen);
integer finish;
extern doublereal dlanst_(char *, integer *, doublereal *, doublereal *, ftnlen);
extern int dsterf_(integer *, doublereal *, doublereal *, integer *),
dlasrt_(char *, integer *, doublereal *, integer *, ftnlen);
integer liwmin, icompz;
extern int dsteqr_(char *, integer *, doublereal *, doublereal *, doublereal *, integer *,
doublereal *, integer *, ftnlen);
doublereal orgnrm;
logical lquery;
integer smlsiz, storez, strtrw;
--d__;
--e;
z_dim1 = *ldz;
z_offset = 1 + z_dim1;
z__ -= z_offset;
--work;
--iwork;
*info = 0;
lquery = *lwork == -1 || *liwork == -1;
if (lsame_(compz, (char *)"N", (ftnlen)1, (ftnlen)1)) {
icompz = 0;
} else if (lsame_(compz, (char *)"V", (ftnlen)1, (ftnlen)1)) {
icompz = 1;
} else if (lsame_(compz, (char *)"I", (ftnlen)1, (ftnlen)1)) {
icompz = 2;
} else {
icompz = -1;
}
if (icompz < 0) {
*info = -1;
} else if (*n < 0) {
*info = -2;
} else if (*ldz < 1 || icompz > 0 && *ldz < max(1, *n)) {
*info = -6;
}
if (*info == 0) {
smlsiz = ilaenv_(&c__9, (char *)"DSTEDC", (char *)" ", &c__0, &c__0, &c__0, &c__0, (ftnlen)6, (ftnlen)1);
if (*n <= 1 || icompz == 0) {
liwmin = 1;
lwmin = 1;
} else if (*n <= smlsiz) {
liwmin = 1;
lwmin = *n - 1 << 1;
} else {
lgn = (integer)(log((doublereal)(*n)) / log(2.));
if (pow_lmp_ii(&c__2, &lgn) < *n) {
++lgn;
}
if (pow_lmp_ii(&c__2, &lgn) < *n) {
++lgn;
}
if (icompz == 1) {
i__1 = *n;
lwmin = *n * 3 + 1 + (*n << 1) * lgn + (i__1 * i__1 << 2);
liwmin = *n * 6 + 6 + *n * 5 * lgn;
} else if (icompz == 2) {
i__1 = *n;
lwmin = (*n << 2) + 1 + i__1 * i__1;
liwmin = *n * 5 + 3;
}
}
work[1] = (doublereal)lwmin;
iwork[1] = liwmin;
if (*lwork < lwmin && !lquery) {
*info = -8;
} else if (*liwork < liwmin && !lquery) {
*info = -10;
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_((char *)"DSTEDC", &i__1, (ftnlen)6);
return 0;
} else if (lquery) {
return 0;
}
if (*n == 0) {
return 0;
}
if (*n == 1) {
if (icompz != 0) {
z__[z_dim1 + 1] = 1.;
}
return 0;
}
if (icompz == 0) {
dsterf_(n, &d__[1], &e[1], info);
goto L50;
}
if (*n <= smlsiz) {
dsteqr_(compz, n, &d__[1], &e[1], &z__[z_offset], ldz, &work[1], info, (ftnlen)1);
} else {
if (icompz == 1) {
storez = *n * *n + 1;
} else {
storez = 1;
}
if (icompz == 2) {
dlaset_((char *)"F", n, n, &c_b17, &c_b18, &z__[z_offset], ldz, (ftnlen)1);
}
orgnrm = dlanst_((char *)"M", n, &d__[1], &e[1], (ftnlen)1);
if (orgnrm == 0.) {
goto L50;
}
eps = dlamch_((char *)"Epsilon", (ftnlen)7);
start = 1;
L10:
if (start <= *n) {
finish = start;
L20:
if (finish < *n) {
tiny = eps * sqrt((d__1 = d__[finish], abs(d__1))) *
sqrt((d__2 = d__[finish + 1], abs(d__2)));
if ((d__1 = e[finish], abs(d__1)) > tiny) {
++finish;
goto L20;
}
}
m = finish - start + 1;
if (m == 1) {
start = finish + 1;
goto L10;
}
if (m > smlsiz) {
orgnrm = dlanst_((char *)"M", &m, &d__[start], &e[start], (ftnlen)1);
dlascl_((char *)"G", &c__0, &c__0, &orgnrm, &c_b18, &m, &c__1, &d__[start], &m, info,
(ftnlen)1);
i__1 = m - 1;
i__2 = m - 1;
dlascl_((char *)"G", &c__0, &c__0, &orgnrm, &c_b18, &i__1, &c__1, &e[start], &i__2, info,
(ftnlen)1);
if (icompz == 1) {
strtrw = 1;
} else {
strtrw = start;
}
dlaed0_(&icompz, n, &m, &d__[start], &e[start], &z__[strtrw + start * z_dim1], ldz,
&work[1], n, &work[storez], &iwork[1], info);
if (*info != 0) {
*info = (*info / (m + 1) + start - 1) * (*n + 1) + *info % (m + 1) + start - 1;
goto L50;
}
dlascl_((char *)"G", &c__0, &c__0, &c_b18, &orgnrm, &m, &c__1, &d__[start], &m, info,
(ftnlen)1);
} else {
if (icompz == 1) {
dsteqr_((char *)"I", &m, &d__[start], &e[start], &work[1], &m, &work[m * m + 1], info,
(ftnlen)1);
dlacpy_((char *)"A", n, &m, &z__[start * z_dim1 + 1], ldz, &work[storez], n, (ftnlen)1);
dgemm_((char *)"N", (char *)"N", n, &m, &m, &c_b18, &work[storez], n, &work[1], &m, &c_b17,
&z__[start * z_dim1 + 1], ldz, (ftnlen)1, (ftnlen)1);
} else if (icompz == 2) {
dsteqr_((char *)"I", &m, &d__[start], &e[start], &z__[start + start * z_dim1], ldz,
&work[1], info, (ftnlen)1);
} else {
dsterf_(&m, &d__[start], &e[start], info);
}
if (*info != 0) {
*info = start * (*n + 1) + finish;
goto L50;
}
}
start = finish + 1;
goto L10;
}
if (icompz == 0) {
dlasrt_((char *)"I", n, &d__[1], info, (ftnlen)1);
} else {
i__1 = *n;
for (ii = 2; ii <= i__1; ++ii) {
i__ = ii - 1;
k = i__;
p = d__[i__];
i__2 = *n;
for (j = ii; j <= i__2; ++j) {
if (d__[j] < p) {
k = j;
p = d__[j];
}
}
if (k != i__) {
d__[k] = d__[i__];
d__[i__] = p;
dswap_(n, &z__[i__ * z_dim1 + 1], &c__1, &z__[k * z_dim1 + 1], &c__1);
}
}
}
}
L50:
work[1] = (doublereal)lwmin;
iwork[1] = liwmin;
return 0;
}
#ifdef __cplusplus
}
#endif