#ifdef __cplusplus extern "C" { #endif #include "lmp_f2c.h" static integer c__1 = 1; static doublereal c_b8 = -1.; int dgetf2_(integer *m, integer *n, doublereal *a, integer *lda, integer *ipiv, integer *info) { integer a_dim1, a_offset, i__1, i__2, i__3; doublereal d__1; integer i__, j, jp; extern int dger_(integer *, integer *, doublereal *, doublereal *, integer *, doublereal *, integer *, doublereal *, integer *), dscal_(integer *, doublereal *, doublereal *, integer *); doublereal sfmin; extern int dswap_(integer *, doublereal *, integer *, doublereal *, integer *); extern doublereal dlamch_(char *, ftnlen); extern integer idamax_(integer *, doublereal *, integer *); extern int xerbla_(char *, integer *, ftnlen); a_dim1 = *lda; a_offset = 1 + a_dim1; a -= a_offset; --ipiv; *info = 0; if (*m < 0) { *info = -1; } else if (*n < 0) { *info = -2; } else if (*lda < max(1, *m)) { *info = -4; } if (*info != 0) { i__1 = -(*info); xerbla_((char *)"DGETF2", &i__1, (ftnlen)6); return 0; } if (*m == 0 || *n == 0) { return 0; } sfmin = dlamch_((char *)"S", (ftnlen)1); i__1 = min(*m, *n); for (j = 1; j <= i__1; ++j) { i__2 = *m - j + 1; jp = j - 1 + idamax_(&i__2, &a[j + j * a_dim1], &c__1); ipiv[j] = jp; if (a[jp + j * a_dim1] != 0.) { if (jp != j) { dswap_(n, &a[j + a_dim1], lda, &a[jp + a_dim1], lda); } if (j < *m) { if ((d__1 = a[j + j * a_dim1], abs(d__1)) >= sfmin) { i__2 = *m - j; d__1 = 1. / a[j + j * a_dim1]; dscal_(&i__2, &d__1, &a[j + 1 + j * a_dim1], &c__1); } else { i__2 = *m - j; for (i__ = 1; i__ <= i__2; ++i__) { a[j + i__ + j * a_dim1] /= a[j + j * a_dim1]; } } } } else if (*info == 0) { *info = j; } if (j < min(*m, *n)) { i__2 = *m - j; i__3 = *n - j; dger_(&i__2, &i__3, &c_b8, &a[j + 1 + j * a_dim1], &c__1, &a[j + (j + 1) * a_dim1], lda, &a[j + 1 + (j + 1) * a_dim1], lda); } } return 0; } #ifdef __cplusplus } #endif