55 lines
1.6 KiB
C++
55 lines
1.6 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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int dgeqr2_(integer *m, integer *n, doublereal *a, integer *lda, doublereal *tau, doublereal *work,
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integer *info)
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{
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integer a_dim1, a_offset, i__1, i__2, i__3;
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integer i__, k;
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doublereal aii;
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extern int dlarf_(char *, integer *, integer *, doublereal *, integer *, doublereal *,
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doublereal *, integer *, doublereal *, ftnlen),
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dlarfg_(integer *, doublereal *, doublereal *, integer *, doublereal *),
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xerbla_(char *, integer *, ftnlen);
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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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--tau;
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--work;
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*info = 0;
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if (*m < 0) {
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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, *m)) {
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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 *)"DGEQR2", &i__1, (ftnlen)6);
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return 0;
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}
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k = min(*m, *n);
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i__1 = k;
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for (i__ = 1; i__ <= i__1; ++i__) {
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i__2 = *m - i__ + 1;
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i__3 = i__ + 1;
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dlarfg_(&i__2, &a[i__ + i__ * a_dim1], &a[min(i__3, *m) + i__ * a_dim1], &c__1, &tau[i__]);
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if (i__ < *n) {
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aii = a[i__ + i__ * a_dim1];
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a[i__ + i__ * a_dim1] = 1.;
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i__2 = *m - i__ + 1;
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i__3 = *n - i__;
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dlarf_((char *)"Left", &i__2, &i__3, &a[i__ + i__ * a_dim1], &c__1, &tau[i__],
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&a[i__ + (i__ + 1) * a_dim1], lda, &work[1], (ftnlen)4);
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a[i__ + i__ * a_dim1] = aii;
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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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