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/* eispack/eltran.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"
/*< subroutine eltran(nm,n,low,igh,a,int,z) >*/
/* Subroutine */ int eltran_(integer *nm, integer *n, integer *low, integer *
igh, doublereal *a, integer *int__, doublereal *z__)
{
/* System generated locals */
integer a_dim1, a_offset, z_dim1, z_offset, i__1, i__2;
/* Local variables */
integer i__, j, kl, mm, mp, mp1;
/*< integer i,j,n,kl,mm,mp,nm,igh,low,mp1 >*/
/*< double precision a(nm,igh),z(nm,n) >*/
/*< integer int(igh) >*/
/* this subroutine is a translation of the algol procedure elmtrans, */
/* num. math. 16, 181-204(1970) by peters and wilkinson. */
/* handbook for auto. comp., vol.ii-linear algebra, 372-395(1971). */
/* this subroutine accumulates the stabilized elementary */
/* similarity transformations used in the reduction of a */
/* real general matrix to upper hessenberg form by elmhes. */
/* on input */
/* nm must be set to the row dimension of two-dimensional */
/* array parameters as declared in the calling program */
/* dimension statement. */
/* n is the order of the matrix. */
/* low and igh are integers determined by the balancing */
/* subroutine balanc. if balanc has not been used, */
/* set low=1, igh=n. */
/* a contains the multipliers which were used in the */
/* reduction by elmhes in its lower triangle */
/* below the subdiagonal. */
/* int contains information on the rows and columns */
/* interchanged in the reduction by elmhes. */
/* only elements low through igh are used. */
/* on output */
/* z contains the transformation matrix produced in the */
/* reduction by elmhes. */
/* questions and comments should be directed to burton s. garbow, */
/* mathematics and computer science div, argonne national laboratory */
/* this version dated august 1983. */
/* ------------------------------------------------------------------ */
/* .......... initialize z to identity matrix .......... */
/*< do 80 j = 1, n >*/
/* Parameter adjustments */
z_dim1 = *nm;
z_offset = 1 + z_dim1;
z__ -= z_offset;
--int__;
a_dim1 = *nm;
a_offset = 1 + a_dim1;
a -= a_offset;
/* Function Body */
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
/*< do 60 i = 1, n >*/
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
/*< 60 z(i,j) = 0.0d0 >*/
/* L60: */
z__[i__ + j * z_dim1] = 0.;
}
/*< z(j,j) = 1.0d0 >*/
z__[j + j * z_dim1] = 1.;
/*< 80 continue >*/
/* L80: */
}
/*< kl = igh - low - 1 >*/
kl = *igh - *low - 1;
/*< if (kl .lt. 1) go to 200 >*/
if (kl < 1) {
goto L200;
}
/* .......... for mp=igh-1 step -1 until low+1 do -- .......... */
/*< do 140 mm = 1, kl >*/
i__1 = kl;
for (mm = 1; mm <= i__1; ++mm) {
/*< mp = igh - mm >*/
mp = *igh - mm;
/*< mp1 = mp + 1 >*/
mp1 = mp + 1;
/*< do 100 i = mp1, igh >*/
i__2 = *igh;
for (i__ = mp1; i__ <= i__2; ++i__) {
/*< 100 z(i,mp) = a(i,mp-1) >*/
/* L100: */
z__[i__ + mp * z_dim1] = a[i__ + (mp - 1) * a_dim1];
}
/*< i = int(mp) >*/
i__ = int__[mp];
/*< if (i .eq. mp) go to 140 >*/
if (i__ == mp) {
goto L140;
}
/*< do 130 j = mp, igh >*/
i__2 = *igh;
for (j = mp; j <= i__2; ++j) {
/*< z(mp,j) = z(i,j) >*/
z__[mp + j * z_dim1] = z__[i__ + j * z_dim1];
/*< z(i,j) = 0.0d0 >*/
z__[i__ + j * z_dim1] = 0.;
/*< 130 continue >*/
/* L130: */
}
/*< z(i,mp) = 1.0d0 >*/
z__[i__ + mp * z_dim1] = 1.;
/*< 140 continue >*/
L140:
;
}
/*< 200 return >*/
L200:
return 0;
/*< end >*/
} /* eltran_ */
#ifdef __cplusplus
}
#endif
|
