247 lines
8.9 KiB
C++
247 lines
8.9 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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int dsytf2_(char *uplo, integer *n, doublereal *a, integer *lda, integer *ipiv, integer *info,
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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, d__2, d__3;
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double sqrt(doublereal);
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integer i__, j, k;
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doublereal t, r1, d11, d12, d21, d22;
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integer kk, kp;
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doublereal wk, wkm1, wkp1;
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integer imax, jmax;
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extern int dsyr_(char *, integer *, doublereal *, doublereal *, integer *, doublereal *,
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integer *, ftnlen);
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doublereal alpha;
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extern int dscal_(integer *, doublereal *, doublereal *, integer *);
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extern logical lsame_(char *, char *, ftnlen, ftnlen);
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extern int dswap_(integer *, doublereal *, integer *, doublereal *, integer *);
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integer kstep;
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logical upper;
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doublereal absakk;
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extern integer idamax_(integer *, doublereal *, integer *);
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extern logical disnan_(doublereal *);
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extern int xerbla_(char *, integer *, ftnlen);
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doublereal colmax, rowmax;
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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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--ipiv;
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*info = 0;
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upper = lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1);
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if (!upper && !lsame_(uplo, (char *)"L", (ftnlen)1, (ftnlen)1)) {
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*info = -1;
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} else if (*n < 0) {
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*info = -2;
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} else if (*lda < max(1, *n)) {
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*info = -4;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_((char *)"DSYTF2", &i__1, (ftnlen)6);
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return 0;
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}
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alpha = (sqrt(17.) + 1.) / 8.;
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if (upper) {
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k = *n;
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L10:
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if (k < 1) {
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goto L70;
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}
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kstep = 1;
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absakk = (d__1 = a[k + k * a_dim1], abs(d__1));
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if (k > 1) {
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i__1 = k - 1;
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imax = idamax_(&i__1, &a[k * a_dim1 + 1], &c__1);
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colmax = (d__1 = a[imax + k * a_dim1], abs(d__1));
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} else {
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colmax = 0.;
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}
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if (max(absakk, colmax) == 0. || disnan_(&absakk)) {
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if (*info == 0) {
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*info = k;
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}
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kp = k;
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} else {
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if (absakk >= alpha * colmax) {
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kp = k;
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} else {
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i__1 = k - imax;
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jmax = imax + idamax_(&i__1, &a[imax + (imax + 1) * a_dim1], lda);
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rowmax = (d__1 = a[imax + jmax * a_dim1], abs(d__1));
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if (imax > 1) {
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i__1 = imax - 1;
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jmax = idamax_(&i__1, &a[imax * a_dim1 + 1], &c__1);
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d__2 = rowmax, d__3 = (d__1 = a[jmax + imax * a_dim1], abs(d__1));
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rowmax = max(d__2, d__3);
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}
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if (absakk >= alpha * colmax * (colmax / rowmax)) {
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kp = k;
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} else if ((d__1 = a[imax + imax * a_dim1], abs(d__1)) >= alpha * rowmax) {
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kp = imax;
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} else {
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kp = imax;
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kstep = 2;
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}
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}
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kk = k - kstep + 1;
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if (kp != kk) {
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i__1 = kp - 1;
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dswap_(&i__1, &a[kk * a_dim1 + 1], &c__1, &a[kp * a_dim1 + 1], &c__1);
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i__1 = kk - kp - 1;
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dswap_(&i__1, &a[kp + 1 + kk * a_dim1], &c__1, &a[kp + (kp + 1) * a_dim1], lda);
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t = a[kk + kk * a_dim1];
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a[kk + kk * a_dim1] = a[kp + kp * a_dim1];
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a[kp + kp * a_dim1] = t;
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if (kstep == 2) {
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t = a[k - 1 + k * a_dim1];
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a[k - 1 + k * a_dim1] = a[kp + k * a_dim1];
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a[kp + k * a_dim1] = t;
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}
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}
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if (kstep == 1) {
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r1 = 1. / a[k + k * a_dim1];
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i__1 = k - 1;
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d__1 = -r1;
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dsyr_(uplo, &i__1, &d__1, &a[k * a_dim1 + 1], &c__1, &a[a_offset], lda, (ftnlen)1);
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i__1 = k - 1;
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dscal_(&i__1, &r1, &a[k * a_dim1 + 1], &c__1);
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} else {
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if (k > 2) {
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d12 = a[k - 1 + k * a_dim1];
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d22 = a[k - 1 + (k - 1) * a_dim1] / d12;
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d11 = a[k + k * a_dim1] / d12;
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t = 1. / (d11 * d22 - 1.);
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d12 = t / d12;
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for (j = k - 2; j >= 1; --j) {
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wkm1 = d12 * (d11 * a[j + (k - 1) * a_dim1] - a[j + k * a_dim1]);
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wk = d12 * (d22 * a[j + k * a_dim1] - a[j + (k - 1) * a_dim1]);
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for (i__ = j; i__ >= 1; --i__) {
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a[i__ + j * a_dim1] = a[i__ + j * a_dim1] - a[i__ + k * a_dim1] * wk -
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a[i__ + (k - 1) * a_dim1] * wkm1;
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}
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a[j + k * a_dim1] = wk;
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a[j + (k - 1) * a_dim1] = wkm1;
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}
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}
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}
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}
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if (kstep == 1) {
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ipiv[k] = kp;
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} else {
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ipiv[k] = -kp;
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ipiv[k - 1] = -kp;
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}
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k -= kstep;
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goto L10;
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} else {
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k = 1;
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L40:
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if (k > *n) {
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goto L70;
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}
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kstep = 1;
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absakk = (d__1 = a[k + k * a_dim1], abs(d__1));
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if (k < *n) {
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i__1 = *n - k;
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imax = k + idamax_(&i__1, &a[k + 1 + k * a_dim1], &c__1);
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colmax = (d__1 = a[imax + k * a_dim1], abs(d__1));
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} else {
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colmax = 0.;
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}
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if (max(absakk, colmax) == 0. || disnan_(&absakk)) {
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if (*info == 0) {
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*info = k;
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}
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kp = k;
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} else {
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if (absakk >= alpha * colmax) {
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kp = k;
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} else {
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i__1 = imax - k;
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jmax = k - 1 + idamax_(&i__1, &a[imax + k * a_dim1], lda);
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rowmax = (d__1 = a[imax + jmax * a_dim1], abs(d__1));
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if (imax < *n) {
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i__1 = *n - imax;
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jmax = imax + idamax_(&i__1, &a[imax + 1 + imax * a_dim1], &c__1);
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d__2 = rowmax, d__3 = (d__1 = a[jmax + imax * a_dim1], abs(d__1));
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rowmax = max(d__2, d__3);
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}
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if (absakk >= alpha * colmax * (colmax / rowmax)) {
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kp = k;
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} else if ((d__1 = a[imax + imax * a_dim1], abs(d__1)) >= alpha * rowmax) {
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kp = imax;
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} else {
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kp = imax;
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kstep = 2;
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}
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}
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kk = k + kstep - 1;
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if (kp != kk) {
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if (kp < *n) {
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i__1 = *n - kp;
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dswap_(&i__1, &a[kp + 1 + kk * a_dim1], &c__1, &a[kp + 1 + kp * a_dim1], &c__1);
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}
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i__1 = kp - kk - 1;
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dswap_(&i__1, &a[kk + 1 + kk * a_dim1], &c__1, &a[kp + (kk + 1) * a_dim1], lda);
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t = a[kk + kk * a_dim1];
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a[kk + kk * a_dim1] = a[kp + kp * a_dim1];
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a[kp + kp * a_dim1] = t;
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if (kstep == 2) {
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t = a[k + 1 + k * a_dim1];
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a[k + 1 + k * a_dim1] = a[kp + k * a_dim1];
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a[kp + k * a_dim1] = t;
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}
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}
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if (kstep == 1) {
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if (k < *n) {
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d11 = 1. / a[k + k * a_dim1];
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i__1 = *n - k;
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d__1 = -d11;
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dsyr_(uplo, &i__1, &d__1, &a[k + 1 + k * a_dim1], &c__1,
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&a[k + 1 + (k + 1) * a_dim1], lda, (ftnlen)1);
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i__1 = *n - k;
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dscal_(&i__1, &d11, &a[k + 1 + k * a_dim1], &c__1);
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}
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} else {
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if (k < *n - 1) {
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d21 = a[k + 1 + k * a_dim1];
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d11 = a[k + 1 + (k + 1) * a_dim1] / d21;
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d22 = a[k + k * a_dim1] / d21;
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t = 1. / (d11 * d22 - 1.);
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d21 = t / d21;
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i__1 = *n;
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for (j = k + 2; j <= i__1; ++j) {
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wk = d21 * (d11 * a[j + k * a_dim1] - a[j + (k + 1) * a_dim1]);
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wkp1 = d21 * (d22 * a[j + (k + 1) * a_dim1] - a[j + k * a_dim1]);
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i__2 = *n;
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for (i__ = j; i__ <= i__2; ++i__) {
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a[i__ + j * a_dim1] = a[i__ + j * a_dim1] - a[i__ + k * a_dim1] * wk -
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a[i__ + (k + 1) * a_dim1] * wkp1;
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}
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a[j + k * a_dim1] = wk;
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a[j + (k + 1) * a_dim1] = wkp1;
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}
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}
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}
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}
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if (kstep == 1) {
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ipiv[k] = kp;
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} else {
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ipiv[k] = -kp;
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ipiv[k + 1] = -kp;
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}
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k += kstep;
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goto L40;
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}
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L70:
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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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