/* dopmtr.f -- translated by f2c (version 20061008).
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
*/
#include "f2c.h"
#include "blaswrap.h"
/* Table of constant values */
static integer c__1 = 1;
/* Subroutine */ int dopmtr_(char *side, char *uplo, char *trans, integer *m,
integer *n, doublereal *ap, doublereal *tau, doublereal *c__, integer
*ldc, doublereal *work, integer *info)
{
/* System generated locals */
integer c_dim1, c_offset, i__1, i__2;
/* Local variables */
integer i__, i1, i2, i3, ic, jc, ii, mi, ni, nq;
doublereal aii;
logical left;
extern /* Subroutine */ int dlarf_(char *, integer *, integer *,
doublereal *, integer *, doublereal *, doublereal *, integer *,
doublereal *);
extern logical lsame_(char *, char *);
logical upper;
extern /* Subroutine */ int xerbla_(char *, integer *);
logical notran, forwrd;
/* -- LAPACK routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* DOPMTR overwrites the general real M-by-N matrix C with */
/* SIDE = 'L' SIDE = 'R' */
/* TRANS = 'N': Q * C C * Q */
/* TRANS = 'T': Q**T * C C * Q**T */
/* where Q is a real orthogonal matrix of order nq, with nq = m if */
/* SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of */
/* nq-1 elementary reflectors, as returned by DSPTRD using packed */
/* storage: */
/* if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1); */
/* if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1). */
/* Arguments */
/* ========= */
/* SIDE (input) CHARACTER*1 */
/* = 'L': apply Q or Q**T from the Left; */
/* = 'R': apply Q or Q**T from the Right. */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangular packed storage used in previous */
/* call to DSPTRD; */
/* = 'L': Lower triangular packed storage used in previous */
/* call to DSPTRD. */
/* TRANS (input) CHARACTER*1 */
/* = 'N': No transpose, apply Q; */
/* = 'T': Transpose, apply Q**T. */
/* M (input) INTEGER */
/* The number of rows of the matrix C. M >= 0. */
/* N (input) INTEGER */
/* The number of columns of the matrix C. N >= 0. */
/* AP (input) DOUBLE PRECISION array, dimension */
/* (M*(M+1)/2) if SIDE = 'L' */
/* (N*(N+1)/2) if SIDE = 'R' */
/* The vectors which define the elementary reflectors, as */
/* returned by DSPTRD. AP is modified by the routine but */
/* restored on exit. */
/* TAU (input) DOUBLE PRECISION array, dimension (M-1) if SIDE = 'L' */
/* or (N-1) if SIDE = 'R' */
/* TAU(i) must contain the scalar factor of the elementary */
/* reflector H(i), as returned by DSPTRD. */
/* C (input/output) DOUBLE PRECISION array, dimension (LDC,N) */
/* On entry, the M-by-N matrix C. */
/* On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q. */
/* LDC (input) INTEGER */
/* The leading dimension of the array C. LDC >= max(1,M). */
/* WORK (workspace) DOUBLE PRECISION array, dimension */
/* (N) if SIDE = 'L' */
/* (M) if SIDE = 'R' */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input arguments */
/* Parameter adjustments */
--ap;
--tau;
c_dim1 = *ldc;
c_offset = 1 + c_dim1;
c__ -= c_offset;
--work;
/* Function Body */
*info = 0;
left = lsame_(side, "L");
notran = lsame_(trans, "N");
upper = lsame_(uplo, "U");
/* NQ is the order of Q */
if (left) {
nq = *m;
} else {
nq = *n;
}
if (! left && ! lsame_(side, "R")) {
*info = -1;
} else if (! upper && ! lsame_(uplo, "L")) {
*info = -2;
} else if (! notran && ! lsame_(trans, "T")) {
*info = -3;
} else if (*m < 0) {
*info = -4;
} else if (*n < 0) {
*info = -5;
} else if (*ldc < max(1,*m)) {
*info = -9;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("DOPMTR", &i__1);
return 0;
}
/* Quick return if possible */
if (*m == 0 || *n == 0) {
return 0;
}
if (upper) {
/* Q was determined by a call to DSPTRD with UPLO = 'U' */
forwrd = left && notran || ! left && ! notran;
if (forwrd) {
i1 = 1;
i2 = nq - 1;
i3 = 1;
ii = 2;
} else {
i1 = nq - 1;
i2 = 1;
i3 = -1;
ii = nq * (nq + 1) / 2 - 1;
}
if (left) {
ni = *n;
} else {
mi = *m;
}
i__1 = i2;
i__2 = i3;
for (i__ = i1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
if (left) {
/* H(i) is applied to C(1:i,1:n) */
mi = i__;
} else {
/* H(i) is applied to C(1:m,1:i) */
ni = i__;
}
/* Apply H(i) */
aii = ap[ii];
ap[ii] = 1.;
dlarf_(side, &mi, &ni, &ap[ii - i__ + 1], &c__1, &tau[i__], &c__[
c_offset], ldc, &work[1]);
ap[ii] = aii;
if (forwrd) {
ii = ii + i__ + 2;
} else {
ii = ii - i__ - 1;
}
/* L10: */
}
} else {
/* Q was determined by a call to DSPTRD with UPLO = 'L'. */
forwrd = left && ! notran || ! left && notran;
if (forwrd) {
i1 = 1;
i2 = nq - 1;
i3 = 1;
ii = 2;
} else {
i1 = nq - 1;
i2 = 1;
i3 = -1;
ii = nq * (nq + 1) / 2 - 1;
}
if (left) {
ni = *n;
jc = 1;
} else {
mi = *m;
ic = 1;
}
i__2 = i2;
i__1 = i3;
for (i__ = i1; i__1 < 0 ? i__ >= i__2 : i__ <= i__2; i__ += i__1) {
aii = ap[ii];
ap[ii] = 1.;
if (left) {
/* H(i) is applied to C(i+1:m,1:n) */
mi = *m - i__;
ic = i__ + 1;
} else {
/* H(i) is applied to C(1:m,i+1:n) */
ni = *n - i__;
jc = i__ + 1;
}
/* Apply H(i) */
dlarf_(side, &mi, &ni, &ap[ii], &c__1, &tau[i__], &c__[ic + jc *
c_dim1], ldc, &work[1]);
ap[ii] = aii;
if (forwrd) {
ii = ii + nq - i__ + 1;
} else {
ii = ii - nq + i__ - 2;
}
/* L20: */
}
}
return 0;
/* End of DOPMTR */
} /* dopmtr_ */