142 lines
4.6 KiB
C++
142 lines
4.6 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__1 = 1;
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static integer c_n1 = -1;
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static integer c__0 = 0;
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static doublereal c_b17 = 1.;
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int dsyev_(char *jobz, char *uplo, integer *n, doublereal *a, integer *lda, doublereal *w,
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doublereal *work, integer *lwork, integer *info, ftnlen jobz_len, ftnlen uplo_len)
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{
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integer a_dim1, a_offset, i__1, i__2;
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doublereal d__1;
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double sqrt(doublereal);
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integer nb;
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doublereal eps;
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integer inde;
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doublereal anrm;
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integer imax;
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doublereal rmin, rmax;
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extern int dscal_(integer *, doublereal *, doublereal *, integer *);
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doublereal sigma;
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extern logical lsame_(char *, char *, ftnlen, ftnlen);
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integer iinfo;
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logical lower, wantz;
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extern 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 safmin;
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extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *,
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ftnlen, ftnlen);
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extern int xerbla_(char *, integer *, ftnlen);
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doublereal bignum;
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integer indtau;
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extern int dsterf_(integer *, doublereal *, doublereal *, integer *);
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extern doublereal dlansy_(char *, char *, integer *, doublereal *, integer *, doublereal *,
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ftnlen, ftnlen);
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integer indwrk;
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extern int dorgtr_(char *, integer *, doublereal *, integer *, doublereal *, doublereal *,
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integer *, integer *, ftnlen),
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dsteqr_(char *, integer *, doublereal *, doublereal *, doublereal *, integer *,
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doublereal *, integer *, ftnlen),
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dsytrd_(char *, integer *, doublereal *, integer *, doublereal *, doublereal *,
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doublereal *, doublereal *, integer *, integer *, ftnlen);
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integer llwork;
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doublereal smlnum;
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integer lwkopt;
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logical lquery;
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a_dim1 = *lda;
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a_offset = 1 + a_dim1;
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a -= a_offset;
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--w;
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--work;
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wantz = lsame_(jobz, (char *)"V", (ftnlen)1, (ftnlen)1);
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lower = lsame_(uplo, (char *)"L", (ftnlen)1, (ftnlen)1);
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lquery = *lwork == -1;
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*info = 0;
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if (!(wantz || lsame_(jobz, (char *)"N", (ftnlen)1, (ftnlen)1))) {
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*info = -1;
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} else if (!(lower || lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1))) {
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*info = -2;
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} else if (*n < 0) {
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*info = -3;
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} else if (*lda < max(1, *n)) {
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*info = -5;
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}
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if (*info == 0) {
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nb = ilaenv_(&c__1, (char *)"DSYTRD", uplo, n, &c_n1, &c_n1, &c_n1, (ftnlen)6, (ftnlen)1);
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i__1 = 1, i__2 = (nb + 2) * *n;
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lwkopt = max(i__1, i__2);
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work[1] = (doublereal)lwkopt;
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i__1 = 1, i__2 = *n * 3 - 1;
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if (*lwork < max(i__1, i__2) && !lquery) {
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*info = -8;
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}
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_((char *)"DSYEV ", &i__1, (ftnlen)6);
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return 0;
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} else if (lquery) {
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return 0;
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}
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if (*n == 0) {
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return 0;
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}
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if (*n == 1) {
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w[1] = a[a_dim1 + 1];
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work[1] = 2.;
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if (wantz) {
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a[a_dim1 + 1] = 1.;
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}
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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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eps = dlamch_((char *)"Precision", (ftnlen)9);
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smlnum = safmin / eps;
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bignum = 1. / smlnum;
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rmin = sqrt(smlnum);
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rmax = sqrt(bignum);
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anrm = dlansy_((char *)"M", uplo, n, &a[a_offset], lda, &work[1], (ftnlen)1, (ftnlen)1);
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iscale = 0;
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if (anrm > 0. && anrm < rmin) {
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iscale = 1;
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sigma = rmin / anrm;
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} else if (anrm > rmax) {
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iscale = 1;
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sigma = rmax / anrm;
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}
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if (iscale == 1) {
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dlascl_(uplo, &c__0, &c__0, &c_b17, &sigma, n, n, &a[a_offset], lda, info, (ftnlen)1);
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}
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inde = 1;
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indtau = inde + *n;
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indwrk = indtau + *n;
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llwork = *lwork - indwrk + 1;
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dsytrd_(uplo, n, &a[a_offset], lda, &w[1], &work[inde], &work[indtau], &work[indwrk], &llwork,
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&iinfo, (ftnlen)1);
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if (!wantz) {
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dsterf_(n, &w[1], &work[inde], info);
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} else {
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dorgtr_(uplo, n, &a[a_offset], lda, &work[indtau], &work[indwrk], &llwork, &iinfo,
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(ftnlen)1);
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dsteqr_(jobz, n, &w[1], &work[inde], &a[a_offset], lda, &work[indtau], info, (ftnlen)1);
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}
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if (iscale == 1) {
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if (*info == 0) {
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imax = *n;
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} else {
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imax = *info - 1;
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}
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d__1 = 1. / sigma;
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dscal_(&imax, &d__1, &w[1], &c__1);
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}
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work[1] = (doublereal)lwkopt;
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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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