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/* laso/dortqr.f -- translated by f2c (version 20050501).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#ifdef __cplusplus
extern "C" {
#endif
#include "v3p_netlib.h"
/* Table of constant values */
static integer c__1 = 1;
/* ------------------------------------------------------------------ */
/*< SUBROUTINE DORTQR(NZ, N, NBLOCK, Z, B) >*/
/* Subroutine */ int dortqr_(integer *nz, integer *n, integer *nblock,
doublereal *z__, doublereal *b)
{
/* System generated locals */
integer z_dim1, z_offset, b_dim1, b_offset, i__1, i__2;
doublereal d__1;
/* Builtin functions */
double d_sign(doublereal *, doublereal *);
/* Local variables */
integer i__, j, k, m;
doublereal tau;
extern doublereal ddot_(integer *, doublereal *, integer *, doublereal *,
integer *);
doublereal temp;
extern doublereal dnrm2_(integer *, doublereal *, integer *);
extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *,
integer *);
doublereal sigma;
extern /* Subroutine */ int daxpy_(integer *, doublereal *, doublereal *,
integer *, doublereal *, integer *);
integer length;
/*< INTEGER NZ, N, NBLOCK >*/
/*< DOUBLE PRECISION Z(NZ,1), B(NBLOCK,1) >*/
/* THIS SUBROUTINE COMPUTES THE QR FACTORIZATION OF THE N X NBLOCK */
/* MATRIX Z. Q IS FORMED IN PLACE AND RETURNED IN Z. R IS */
/* RETURNED IN B. */
/*< INTEGER I, J, K, LENGTH, M >*/
/*< DOUBLE PRECISION SIGMA, TAU, TEMP, DDOT, DNRM2, DSIGN >*/
/*< EXTERNAL DAXPY, DDOT, DNRM2, DSCAL >*/
/* THIS SECTION REDUCES Z TO TRIANGULAR FORM. */
/*< DO 30 I=1,NBLOCK >*/
/* Parameter adjustments */
z_dim1 = *nz;
z_offset = 1 + z_dim1;
z__ -= z_offset;
b_dim1 = *nblock;
b_offset = 1 + b_dim1;
b -= b_offset;
/* Function Body */
i__1 = *nblock;
for (i__ = 1; i__ <= i__1; ++i__) {
/* THIS FORMS THE ITH REFLECTION. */
/*< LENGTH = N - I + 1 >*/
length = *n - i__ + 1;
/*< SIGMA = DSIGN(DNRM2(LENGTH,Z(I,I),1),Z(I,I)) >*/
d__1 = dnrm2_(&length, &z__[i__ + i__ * z_dim1], &c__1);
sigma = d_sign(&d__1, &z__[i__ + i__ * z_dim1]);
/*< B(I,I) = -SIGMA >*/
b[i__ + i__ * b_dim1] = -sigma;
/*< Z(I,I) = Z(I,I) + SIGMA >*/
z__[i__ + i__ * z_dim1] += sigma;
/*< TAU = SIGMA*Z(I,I) >*/
tau = sigma * z__[i__ + i__ * z_dim1];
/*< IF (I.EQ.NBLOCK) GO TO 30 >*/
if (i__ == *nblock) {
goto L30;
}
/*< J = I + 1 >*/
j = i__ + 1;
/* THIS APPLIES THE ROTATION TO THE REST OF THE COLUMNS. */
/*< DO 20 K=J,NBLOCK >*/
i__2 = *nblock;
for (k = j; k <= i__2; ++k) {
/*< IF (TAU.EQ.0.0D0) GO TO 10 >*/
if (tau == 0.) {
goto L10;
}
/*< TEMP = -DDOT(LENGTH,Z(I,I),1,Z(I,K),1)/TAU >*/
temp = -ddot_(&length, &z__[i__ + i__ * z_dim1], &c__1, &z__[i__
+ k * z_dim1], &c__1) / tau;
/*< CALL DAXPY(LENGTH, TEMP, Z(I,I), 1, Z(I,K), 1) >*/
daxpy_(&length, &temp, &z__[i__ + i__ * z_dim1], &c__1, &z__[i__
+ k * z_dim1], &c__1);
/*< 10 B(I,K) = Z(I,K) >*/
L10:
b[i__ + k * b_dim1] = z__[i__ + k * z_dim1];
/*< Z(I,K) = 0.0D0 >*/
z__[i__ + k * z_dim1] = 0.;
/*< 20 CONTINUE >*/
/* L20: */
}
/*< 30 CONTINUE >*/
L30:
;
}
/* THIS ACCUMULATES THE REFLECTIONS IN REVERSE ORDER. */
/*< DO 70 M=1,NBLOCK >*/
i__1 = *nblock;
for (m = 1; m <= i__1; ++m) {
/* THIS RECREATES THE ITH = NBLOCK-M+1)TH REFLECTION. */
/*< I = NBLOCK + 1 - M >*/
i__ = *nblock + 1 - m;
/*< SIGMA = -B(I,I) >*/
sigma = -b[i__ + i__ * b_dim1];
/*< TAU = Z(I,I)*SIGMA >*/
tau = z__[i__ + i__ * z_dim1] * sigma;
/*< IF (TAU.EQ.0.0D0) GO TO 60 >*/
if (tau == 0.) {
goto L60;
}
/*< LENGTH = N - NBLOCK + M >*/
length = *n - *nblock + m;
/*< IF (I.EQ.NBLOCK) GO TO 50 >*/
if (i__ == *nblock) {
goto L50;
}
/*< J = I + 1 >*/
j = i__ + 1;
/* THIS APPLIES IT TO THE LATER COLUMNS. */
/*< DO 40 K=J,NBLOCK >*/
i__2 = *nblock;
for (k = j; k <= i__2; ++k) {
/*< TEMP = -DDOT(LENGTH,Z(I,I),1,Z(I,K),1)/TAU >*/
temp = -ddot_(&length, &z__[i__ + i__ * z_dim1], &c__1, &z__[i__
+ k * z_dim1], &c__1) / tau;
/*< CALL DAXPY(LENGTH, TEMP, Z(I,I), 1, Z(I,K), 1) >*/
daxpy_(&length, &temp, &z__[i__ + i__ * z_dim1], &c__1, &z__[i__
+ k * z_dim1], &c__1);
/*< 40 CONTINUE >*/
/* L40: */
}
/*< 50 CALL DSCAL(LENGTH, -1.0D0/SIGMA, Z(I,I), 1) >*/
L50:
d__1 = -1. / sigma;
dscal_(&length, &d__1, &z__[i__ + i__ * z_dim1], &c__1);
/*< 60 Z(I,I) = 1.0D0 + Z(I,I) >*/
L60:
z__[i__ + i__ * z_dim1] += 1.;
/*< 70 CONTINUE >*/
/* L70: */
}
/*< RETURN >*/
return 0;
/*< END >*/
} /* dortqr_ */
#ifdef __cplusplus
}
#endif
|
