/* -- translated by f2c (version 20191129).
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
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
/* > \brief \b DLASR applies a sequence of plane rotations to a general rectangular matrix.
=========== DOCUMENTATION ===========
Online html documentation available at
http://www.netlib.org/lapack/explore-html/
> \htmlonly
> Download DLASR + dependencies
>
> [TGZ]
>
> [ZIP]
>
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> \endhtmlonly
Definition:
===========
SUBROUTINE DLASR( SIDE, PIVOT, DIRECT, M, N, C, S, A, LDA )
CHARACTER DIRECT, PIVOT, SIDE
INTEGER LDA, M, N
DOUBLE PRECISION A( LDA, * ), C( * ), S( * )
> \par Purpose:
=============
>
> \verbatim
>
> DLASR applies a sequence of plane rotations to a real matrix A,
> from either the left or the right.
>
> When SIDE = 'L', the transformation takes the form
>
> A := P*A
>
> and when SIDE = 'R', the transformation takes the form
>
> A := A*P**T
>
> where P is an orthogonal matrix consisting of a sequence of z plane
> rotations, with z = M when SIDE = 'L' and z = N when SIDE = 'R',
> and P**T is the transpose of P.
>
> When DIRECT = 'F' (Forward sequence), then
>
> P = P(z-1) * ... * P(2) * P(1)
>
> and when DIRECT = 'B' (Backward sequence), then
>
> P = P(1) * P(2) * ... * P(z-1)
>
> where P(k) is a plane rotation matrix defined by the 2-by-2 rotation
>
> R(k) = ( c(k) s(k) )
> = ( -s(k) c(k) ).
>
> When PIVOT = 'V' (Variable pivot), the rotation is performed
> for the plane (k,k+1), i.e., P(k) has the form
>
> P(k) = ( 1 )
> ( ... )
> ( 1 )
> ( c(k) s(k) )
> ( -s(k) c(k) )
> ( 1 )
> ( ... )
> ( 1 )
>
> where R(k) appears as a rank-2 modification to the identity matrix in
> rows and columns k and k+1.
>
> When PIVOT = 'T' (Top pivot), the rotation is performed for the
> plane (1,k+1), so P(k) has the form
>
> P(k) = ( c(k) s(k) )
> ( 1 )
> ( ... )
> ( 1 )
> ( -s(k) c(k) )
> ( 1 )
> ( ... )
> ( 1 )
>
> where R(k) appears in rows and columns 1 and k+1.
>
> Similarly, when PIVOT = 'B' (Bottom pivot), the rotation is
> performed for the plane (k,z), giving P(k) the form
>
> P(k) = ( 1 )
> ( ... )
> ( 1 )
> ( c(k) s(k) )
> ( 1 )
> ( ... )
> ( 1 )
> ( -s(k) c(k) )
>
> where R(k) appears in rows and columns k and z. The rotations are
> performed without ever forming P(k) explicitly.
> \endverbatim
Arguments:
==========
> \param[in] SIDE
> \verbatim
> SIDE is CHARACTER*1
> Specifies whether the plane rotation matrix P is applied to
> A on the left or the right.
> = 'L': Left, compute A := P*A
> = 'R': Right, compute A:= A*P**T
> \endverbatim
>
> \param[in] PIVOT
> \verbatim
> PIVOT is CHARACTER*1
> Specifies the plane for which P(k) is a plane rotation
> matrix.
> = 'V': Variable pivot, the plane (k,k+1)
> = 'T': Top pivot, the plane (1,k+1)
> = 'B': Bottom pivot, the plane (k,z)
> \endverbatim
>
> \param[in] DIRECT
> \verbatim
> DIRECT is CHARACTER*1
> Specifies whether P is a forward or backward sequence of
> plane rotations.
> = 'F': Forward, P = P(z-1)*...*P(2)*P(1)
> = 'B': Backward, P = P(1)*P(2)*...*P(z-1)
> \endverbatim
>
> \param[in] M
> \verbatim
> M is INTEGER
> The number of rows of the matrix A. If m <= 1, an immediate
> return is effected.
> \endverbatim
>
> \param[in] N
> \verbatim
> N is INTEGER
> The number of columns of the matrix A. If n <= 1, an
> immediate return is effected.
> \endverbatim
>
> \param[in] C
> \verbatim
> C is DOUBLE PRECISION array, dimension
> (M-1) if SIDE = 'L'
> (N-1) if SIDE = 'R'
> The cosines c(k) of the plane rotations.
> \endverbatim
>
> \param[in] S
> \verbatim
> S is DOUBLE PRECISION array, dimension
> (M-1) if SIDE = 'L'
> (N-1) if SIDE = 'R'
> The sines s(k) of the plane rotations. The 2-by-2 plane
> rotation part of the matrix P(k), R(k), has the form
> R(k) = ( c(k) s(k) )
> ( -s(k) c(k) ).
> \endverbatim
>
> \param[in,out] A
> \verbatim
> A is DOUBLE PRECISION array, dimension (LDA,N)
> The M-by-N matrix A. On exit, A is overwritten by P*A if
> SIDE = 'R' or by A*P**T if SIDE = 'L'.
> \endverbatim
>
> \param[in] LDA
> \verbatim
> LDA is INTEGER
> The leading dimension of the array A. LDA >= max(1,M).
> \endverbatim
Authors:
========
> \author Univ. of Tennessee
> \author Univ. of California Berkeley
> \author Univ. of Colorado Denver
> \author NAG Ltd.
> \date September 2012
> \ingroup auxOTHERauxiliary
=====================================================================
Subroutine */ int igraphdlasr_(char *side, char *pivot, char *direct, integer *m,
integer *n, doublereal *c__, doublereal *s, doublereal *a, integer *
lda)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2;
/* Local variables */
integer i__, j, info;
doublereal temp;
extern logical igraphlsame_(char *, char *);
doublereal ctemp, stemp;
extern /* Subroutine */ int igraphxerbla_(char *, integer *, ftnlen);
/* -- LAPACK auxiliary routine (version 3.4.2) --
-- LAPACK is a software package provided by Univ. of Tennessee, --
-- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
September 2012
=====================================================================
Test the input parameters
Parameter adjustments */
--c__;
--s;
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
/* Function Body */
info = 0;
if (! (igraphlsame_(side, "L") || igraphlsame_(side, "R"))) {
info = 1;
} else if (! (igraphlsame_(pivot, "V") || igraphlsame_(pivot,
"T") || igraphlsame_(pivot, "B"))) {
info = 2;
} else if (! (igraphlsame_(direct, "F") || igraphlsame_(direct,
"B"))) {
info = 3;
} else if (*m < 0) {
info = 4;
} else if (*n < 0) {
info = 5;
} else if (*lda < max(1,*m)) {
info = 9;
}
if (info != 0) {
igraphxerbla_("DLASR ", &info, (ftnlen)6);
return 0;
}
/* Quick return if possible */
if (*m == 0 || *n == 0) {
return 0;
}
if (igraphlsame_(side, "L")) {
/* Form P * A */
if (igraphlsame_(pivot, "V")) {
if (igraphlsame_(direct, "F")) {
i__1 = *m - 1;
for (j = 1; j <= i__1; ++j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = a[j + 1 + i__ * a_dim1];
a[j + 1 + i__ * a_dim1] = ctemp * temp - stemp *
a[j + i__ * a_dim1];
a[j + i__ * a_dim1] = stemp * temp + ctemp * a[j
+ i__ * a_dim1];
/* L10: */
}
}
/* L20: */
}
} else if (igraphlsame_(direct, "B")) {
for (j = *m - 1; j >= 1; --j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
temp = a[j + 1 + i__ * a_dim1];
a[j + 1 + i__ * a_dim1] = ctemp * temp - stemp *
a[j + i__ * a_dim1];
a[j + i__ * a_dim1] = stemp * temp + ctemp * a[j
+ i__ * a_dim1];
/* L30: */
}
}
/* L40: */
}
}
} else if (igraphlsame_(pivot, "T")) {
if (igraphlsame_(direct, "F")) {
i__1 = *m;
for (j = 2; j <= i__1; ++j) {
ctemp = c__[j - 1];
stemp = s[j - 1];
if (ctemp != 1. || stemp != 0.) {
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = a[j + i__ * a_dim1];
a[j + i__ * a_dim1] = ctemp * temp - stemp * a[
i__ * a_dim1 + 1];
a[i__ * a_dim1 + 1] = stemp * temp + ctemp * a[
i__ * a_dim1 + 1];
/* L50: */
}
}
/* L60: */
}
} else if (igraphlsame_(direct, "B")) {
for (j = *m; j >= 2; --j) {
ctemp = c__[j - 1];
stemp = s[j - 1];
if (ctemp != 1. || stemp != 0.) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
temp = a[j + i__ * a_dim1];
a[j + i__ * a_dim1] = ctemp * temp - stemp * a[
i__ * a_dim1 + 1];
a[i__ * a_dim1 + 1] = stemp * temp + ctemp * a[
i__ * a_dim1 + 1];
/* L70: */
}
}
/* L80: */
}
}
} else if (igraphlsame_(pivot, "B")) {
if (igraphlsame_(direct, "F")) {
i__1 = *m - 1;
for (j = 1; j <= i__1; ++j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = a[j + i__ * a_dim1];
a[j + i__ * a_dim1] = stemp * a[*m + i__ * a_dim1]
+ ctemp * temp;
a[*m + i__ * a_dim1] = ctemp * a[*m + i__ *
a_dim1] - stemp * temp;
/* L90: */
}
}
/* L100: */
}
} else if (igraphlsame_(direct, "B")) {
for (j = *m - 1; j >= 1; --j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
temp = a[j + i__ * a_dim1];
a[j + i__ * a_dim1] = stemp * a[*m + i__ * a_dim1]
+ ctemp * temp;
a[*m + i__ * a_dim1] = ctemp * a[*m + i__ *
a_dim1] - stemp * temp;
/* L110: */
}
}
/* L120: */
}
}
}
} else if (igraphlsame_(side, "R")) {
/* Form A * P**T */
if (igraphlsame_(pivot, "V")) {
if (igraphlsame_(direct, "F")) {
i__1 = *n - 1;
for (j = 1; j <= i__1; ++j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = a[i__ + (j + 1) * a_dim1];
a[i__ + (j + 1) * a_dim1] = ctemp * temp - stemp *
a[i__ + j * a_dim1];
a[i__ + j * a_dim1] = stemp * temp + ctemp * a[
i__ + j * a_dim1];
/* L130: */
}
}
/* L140: */
}
} else if (igraphlsame_(direct, "B")) {
for (j = *n - 1; j >= 1; --j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__1 = *m;
for (i__ = 1; i__ <= i__1; ++i__) {
temp = a[i__ + (j + 1) * a_dim1];
a[i__ + (j + 1) * a_dim1] = ctemp * temp - stemp *
a[i__ + j * a_dim1];
a[i__ + j * a_dim1] = stemp * temp + ctemp * a[
i__ + j * a_dim1];
/* L150: */
}
}
/* L160: */
}
}
} else if (igraphlsame_(pivot, "T")) {
if (igraphlsame_(direct, "F")) {
i__1 = *n;
for (j = 2; j <= i__1; ++j) {
ctemp = c__[j - 1];
stemp = s[j - 1];
if (ctemp != 1. || stemp != 0.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = a[i__ + j * a_dim1];
a[i__ + j * a_dim1] = ctemp * temp - stemp * a[
i__ + a_dim1];
a[i__ + a_dim1] = stemp * temp + ctemp * a[i__ +
a_dim1];
/* L170: */
}
}
/* L180: */
}
} else if (igraphlsame_(direct, "B")) {
for (j = *n; j >= 2; --j) {
ctemp = c__[j - 1];
stemp = s[j - 1];
if (ctemp != 1. || stemp != 0.) {
i__1 = *m;
for (i__ = 1; i__ <= i__1; ++i__) {
temp = a[i__ + j * a_dim1];
a[i__ + j * a_dim1] = ctemp * temp - stemp * a[
i__ + a_dim1];
a[i__ + a_dim1] = stemp * temp + ctemp * a[i__ +
a_dim1];
/* L190: */
}
}
/* L200: */
}
}
} else if (igraphlsame_(pivot, "B")) {
if (igraphlsame_(direct, "F")) {
i__1 = *n - 1;
for (j = 1; j <= i__1; ++j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = a[i__ + j * a_dim1];
a[i__ + j * a_dim1] = stemp * a[i__ + *n * a_dim1]
+ ctemp * temp;
a[i__ + *n * a_dim1] = ctemp * a[i__ + *n *
a_dim1] - stemp * temp;
/* L210: */
}
}
/* L220: */
}
} else if (igraphlsame_(direct, "B")) {
for (j = *n - 1; j >= 1; --j) {
ctemp = c__[j];
stemp = s[j];
if (ctemp != 1. || stemp != 0.) {
i__1 = *m;
for (i__ = 1; i__ <= i__1; ++i__) {
temp = a[i__ + j * a_dim1];
a[i__ + j * a_dim1] = stemp * a[i__ + *n * a_dim1]
+ ctemp * temp;
a[i__ + *n * a_dim1] = ctemp * a[i__ + *n *
a_dim1] - stemp * temp;
/* L230: */
}
}
/* L240: */
}
}
}
}
return 0;
/* End of DLASR */
} /* igraphdlasr_ */