--- /dev/null
+#include "clapack.h"
+
+/* Table of constant values */
+
+static integer c__1 = 1;
+
+/* Subroutine */ int dorg2r_(integer *m, integer *n, integer *k, doublereal *
+ a, integer *lda, doublereal *tau, doublereal *work, integer *info)
+{
+ /* System generated locals */
+ integer a_dim1, a_offset, i__1, i__2;
+ doublereal d__1;
+
+ /* Local variables */
+ integer i__, j, l;
+ extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *,
+ integer *), dlarf_(char *, integer *, integer *, doublereal *,
+ integer *, doublereal *, doublereal *, integer *, doublereal *), xerbla_(char *, integer *);
+
+
+/* -- LAPACK routine (version 3.1) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/* November 2006 */
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* DORG2R generates an m by n real matrix Q with orthonormal columns, */
+/* which is defined as the first n columns of a product of k elementary */
+/* reflectors of order m */
+
+/* Q = H(1) H(2) . . . H(k) */
+
+/* as returned by DGEQRF. */
+
+/* Arguments */
+/* ========= */
+
+/* M (input) INTEGER */
+/* The number of rows of the matrix Q. M >= 0. */
+
+/* N (input) INTEGER */
+/* The number of columns of the matrix Q. M >= N >= 0. */
+
+/* K (input) INTEGER */
+/* The number of elementary reflectors whose product defines the */
+/* matrix Q. N >= K >= 0. */
+
+/* A (input/output) DOUBLE PRECISION array, dimension (LDA,N) */
+/* On entry, the i-th column must contain the vector which */
+/* defines the elementary reflector H(i), for i = 1,2,...,k, as */
+/* returned by DGEQRF in the first k columns of its array */
+/* argument A. */
+/* On exit, the m-by-n matrix Q. */
+
+/* LDA (input) INTEGER */
+/* The first dimension of the array A. LDA >= max(1,M). */
+
+/* TAU (input) DOUBLE PRECISION array, dimension (K) */
+/* TAU(i) must contain the scalar factor of the elementary */
+/* reflector H(i), as returned by DGEQRF. */
+
+/* WORK (workspace) DOUBLE PRECISION array, dimension (N) */
+
+/* INFO (output) INTEGER */
+/* = 0: successful exit */
+/* < 0: if INFO = -i, the i-th argument has an illegal value */
+
+/* ===================================================================== */
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. External Subroutines .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Executable Statements .. */
+
+/* Test the input arguments */
+
+ /* Parameter adjustments */
+ a_dim1 = *lda;
+ a_offset = 1 + a_dim1;
+ a -= a_offset;
+ --tau;
+ --work;
+
+ /* Function Body */
+ *info = 0;
+ if (*m < 0) {
+ *info = -1;
+ } else if (*n < 0 || *n > *m) {
+ *info = -2;
+ } else if (*k < 0 || *k > *n) {
+ *info = -3;
+ } else if (*lda < max(1,*m)) {
+ *info = -5;
+ }
+ if (*info != 0) {
+ i__1 = -(*info);
+ xerbla_("DORG2R", &i__1);
+ return 0;
+ }
+
+/* Quick return if possible */
+
+ if (*n <= 0) {
+ return 0;
+ }
+
+/* Initialise columns k+1:n to columns of the unit matrix */
+
+ i__1 = *n;
+ for (j = *k + 1; j <= i__1; ++j) {
+ i__2 = *m;
+ for (l = 1; l <= i__2; ++l) {
+ a[l + j * a_dim1] = 0.;
+/* L10: */
+ }
+ a[j + j * a_dim1] = 1.;
+/* L20: */
+ }
+
+ for (i__ = *k; i__ >= 1; --i__) {
+
+/* Apply H(i) to A(i:m,i:n) from the left */
+
+ if (i__ < *n) {
+ a[i__ + i__ * a_dim1] = 1.;
+ i__1 = *m - i__ + 1;
+ i__2 = *n - i__;
+ dlarf_("Left", &i__1, &i__2, &a[i__ + i__ * a_dim1], &c__1, &tau[
+ i__], &a[i__ + (i__ + 1) * a_dim1], lda, &work[1]);
+ }
+ if (i__ < *m) {
+ i__1 = *m - i__;
+ d__1 = -tau[i__];
+ dscal_(&i__1, &d__1, &a[i__ + 1 + i__ * a_dim1], &c__1);
+ }
+ a[i__ + i__ * a_dim1] = 1. - tau[i__];
+
+/* Set A(1:i-1,i) to zero */
+
+ i__1 = i__ - 1;
+ for (l = 1; l <= i__1; ++l) {
+ a[l + i__ * a_dim1] = 0.;
+/* L30: */
+ }
+/* L40: */
+ }
+ return 0;
+
+/* End of DORG2R */
+
+} /* dorg2r_ */