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|
/* lapack/double/dggbak.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 */ int dggbak_(char *job, char *side, integer *n, integer *ilo,
integer *ihi, doublereal *lscale, doublereal *rscale, integer *m,
doublereal *v, integer *ldv, integer *info, ftnlen job_len, ftnlen
side_len)
{
/* System generated locals */
integer v_dim1, v_offset, i__1;
/* Local variables */
integer i__, k;
extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *,
integer *);
extern logical lsame_(char *, char *, ftnlen, ftnlen);
extern /* Subroutine */ int dswap_(integer *, doublereal *, integer *,
doublereal *, integer *);
logical leftv;
extern /* Subroutine */ int xerbla_(char *, integer *, ftnlen);
logical rightv;
(void)job_len;
(void)side_len;
/* -- LAPACK routine (version 3.0) -- */
/* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., */
/* Courant Institute, Argonne National Lab, and Rice University */
/* September 30, 1994 */
/* .. Scalar Arguments .. */
/*< CHARACTER JOB, SIDE >*/
/*< INTEGER IHI, ILO, INFO, LDV, M, N >*/
/* .. */
/* .. Array Arguments .. */
/*< DOUBLE PRECISION LSCALE( * ), RSCALE( * ), V( LDV, * ) >*/
/* .. */
/* Purpose */
/* ======= */
/* DGGBAK forms the right or left eigenvectors of a real generalized */
/* eigenvalue problem A*x = lambda*B*x, by backward transformation on */
/* the computed eigenvectors of the balanced pair of matrices output by */
/* DGGBAL. */
/* Arguments */
/* ========= */
/* JOB (input) CHARACTER*1 */
/* Specifies the type of backward transformation required: */
/* = 'N': do nothing, return immediately; */
/* = 'P': do backward transformation for permutation only; */
/* = 'S': do backward transformation for scaling only; */
/* = 'B': do backward transformations for both permutation and */
/* scaling. */
/* JOB must be the same as the argument JOB supplied to DGGBAL. */
/* SIDE (input) CHARACTER*1 */
/* = 'R': V contains right eigenvectors; */
/* = 'L': V contains left eigenvectors. */
/* N (input) INTEGER */
/* The number of rows of the matrix V. N >= 0. */
/* ILO (input) INTEGER */
/* IHI (input) INTEGER */
/* The integers ILO and IHI determined by DGGBAL. */
/* 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0. */
/* LSCALE (input) DOUBLE PRECISION array, dimension (N) */
/* Details of the permutations and/or scaling factors applied */
/* to the left side of A and B, as returned by DGGBAL. */
/* RSCALE (input) DOUBLE PRECISION array, dimension (N) */
/* Details of the permutations and/or scaling factors applied */
/* to the right side of A and B, as returned by DGGBAL. */
/* M (input) INTEGER */
/* The number of columns of the matrix V. M >= 0. */
/* V (input/output) DOUBLE PRECISION array, dimension (LDV,M) */
/* On entry, the matrix of right or left eigenvectors to be */
/* transformed, as returned by DTGEVC. */
/* On exit, V is overwritten by the transformed eigenvectors. */
/* LDV (input) INTEGER */
/* The leading dimension of the matrix V. LDV >= max(1,N). */
/* INFO (output) INTEGER */
/* = 0: successful exit. */
/* < 0: if INFO = -i, the i-th argument had an illegal value. */
/* Further Details */
/* =============== */
/* See R.C. Ward, Balancing the generalized eigenvalue problem, */
/* SIAM J. Sci. Stat. Comp. 2 (1981), 141-152. */
/* ===================================================================== */
/* .. Local Scalars .. */
/*< LOGICAL LEFTV, RIGHTV >*/
/*< INTEGER I, K >*/
/* .. */
/* .. External Functions .. */
/*< LOGICAL LSAME >*/
/*< EXTERNAL LSAME >*/
/* .. */
/* .. External Subroutines .. */
/*< EXTERNAL DSCAL, DSWAP, XERBLA >*/
/* .. */
/* .. Intrinsic Functions .. */
/*< INTRINSIC MAX >*/
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters */
/*< RIGHTV = LSAME( SIDE, 'R' ) >*/
/* Parameter adjustments */
--lscale;
--rscale;
v_dim1 = *ldv;
v_offset = 1 + v_dim1;
v -= v_offset;
/* Function Body */
rightv = lsame_(side, "R", (ftnlen)1, (ftnlen)1);
/*< LEFTV = LSAME( SIDE, 'L' ) >*/
leftv = lsame_(side, "L", (ftnlen)1, (ftnlen)1);
/*< INFO = 0 >*/
*info = 0;
/*< >*/
if (! lsame_(job, "N", (ftnlen)1, (ftnlen)1) && ! lsame_(job, "P", (
ftnlen)1, (ftnlen)1) && ! lsame_(job, "S", (ftnlen)1, (ftnlen)1)
&& ! lsame_(job, "B", (ftnlen)1, (ftnlen)1)) {
/*< INFO = -1 >*/
*info = -1;
/*< ELSE IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN >*/
} else if (! rightv && ! leftv) {
/*< INFO = -2 >*/
*info = -2;
/*< ELSE IF( N.LT.0 ) THEN >*/
} else if (*n < 0) {
/*< INFO = -3 >*/
*info = -3;
/*< ELSE IF( ILO.LT.1 ) THEN >*/
} else if (*ilo < 1) {
/*< INFO = -4 >*/
*info = -4;
/*< ELSE IF( IHI.LT.ILO .OR. IHI.GT.MAX( 1, N ) ) THEN >*/
} else if (*ihi < *ilo || *ihi > max(1,*n)) {
/*< INFO = -5 >*/
*info = -5;
/*< ELSE IF( M.LT.0 ) THEN >*/
} else if (*m < 0) {
/*< INFO = -6 >*/
*info = -6;
/*< ELSE IF( LDV.LT.MAX( 1, N ) ) THEN >*/
} else if (*ldv < max(1,*n)) {
/*< INFO = -10 >*/
*info = -10;
/*< END IF >*/
}
/*< IF( INFO.NE.0 ) THEN >*/
if (*info != 0) {
/*< CALL XERBLA( 'DGGBAK', -INFO ) >*/
i__1 = -(*info);
xerbla_("DGGBAK", &i__1, (ftnlen)6);
/*< RETURN >*/
return 0;
/*< END IF >*/
}
/* Quick return if possible */
/*< >*/
if (*n == 0) {
return 0;
}
/*< >*/
if (*m == 0) {
return 0;
}
/*< >*/
if (lsame_(job, "N", (ftnlen)1, (ftnlen)1)) {
return 0;
}
/*< >*/
if (*ilo == *ihi) {
goto L30;
}
/* Backward balance */
/*< IF( LSAME( JOB, 'S' ) .OR. LSAME( JOB, 'B' ) ) THEN >*/
if (lsame_(job, "S", (ftnlen)1, (ftnlen)1) || lsame_(job, "B", (ftnlen)1,
(ftnlen)1)) {
/* Backward transformation on right eigenvectors */
/*< IF( RIGHTV ) THEN >*/
if (rightv) {
/*< DO 10 I = ILO, IHI >*/
i__1 = *ihi;
for (i__ = *ilo; i__ <= i__1; ++i__) {
/*< CALL DSCAL( M, RSCALE( I ), V( I, 1 ), LDV ) >*/
dscal_(m, &rscale[i__], &v[i__ + v_dim1], ldv);
/*< 10 CONTINUE >*/
/* L10: */
}
/*< END IF >*/
}
/* Backward transformation on left eigenvectors */
/*< IF( LEFTV ) THEN >*/
if (leftv) {
/*< DO 20 I = ILO, IHI >*/
i__1 = *ihi;
for (i__ = *ilo; i__ <= i__1; ++i__) {
/*< CALL DSCAL( M, LSCALE( I ), V( I, 1 ), LDV ) >*/
dscal_(m, &lscale[i__], &v[i__ + v_dim1], ldv);
/*< 20 CONTINUE >*/
/* L20: */
}
/*< END IF >*/
}
/*< END IF >*/
}
/* Backward permutation */
/*< 30 CONTINUE >*/
L30:
/*< IF( LSAME( JOB, 'P' ) .OR. LSAME( JOB, 'B' ) ) THEN >*/
if (lsame_(job, "P", (ftnlen)1, (ftnlen)1) || lsame_(job, "B", (ftnlen)1,
(ftnlen)1)) {
/* Backward permutation on right eigenvectors */
/*< IF( RIGHTV ) THEN >*/
if (rightv) {
/*< >*/
if (*ilo == 1) {
goto L50;
}
/*< DO 40 I = ILO - 1, 1, -1 >*/
for (i__ = *ilo - 1; i__ >= 1; --i__) {
/*< K = RSCALE( I ) >*/
k = (integer) rscale[i__];
/*< >*/
if (k == i__) {
goto L40;
}
/*< CALL DSWAP( M, V( I, 1 ), LDV, V( K, 1 ), LDV ) >*/
dswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
/*< 40 CONTINUE >*/
L40:
;
}
/*< 50 CONTINUE >*/
L50:
/*< >*/
if (*ihi == *n) {
goto L70;
}
/*< DO 60 I = IHI + 1, N >*/
i__1 = *n;
for (i__ = *ihi + 1; i__ <= i__1; ++i__) {
/*< K = RSCALE( I ) >*/
k = (integer) rscale[i__];
/*< >*/
if (k == i__) {
goto L60;
}
/*< CALL DSWAP( M, V( I, 1 ), LDV, V( K, 1 ), LDV ) >*/
dswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
/*< 60 CONTINUE >*/
L60:
;
}
/*< END IF >*/
}
/* Backward permutation on left eigenvectors */
/*< 70 CONTINUE >*/
L70:
/*< IF( LEFTV ) THEN >*/
if (leftv) {
/*< >*/
if (*ilo == 1) {
goto L90;
}
/*< DO 80 I = ILO - 1, 1, -1 >*/
for (i__ = *ilo - 1; i__ >= 1; --i__) {
/*< K = LSCALE( I ) >*/
k = (integer) lscale[i__];
/*< >*/
if (k == i__) {
goto L80;
}
/*< CALL DSWAP( M, V( I, 1 ), LDV, V( K, 1 ), LDV ) >*/
dswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
/*< 80 CONTINUE >*/
L80:
;
}
/*< 90 CONTINUE >*/
L90:
/*< >*/
if (*ihi == *n) {
goto L110;
}
/*< DO 100 I = IHI + 1, N >*/
i__1 = *n;
for (i__ = *ihi + 1; i__ <= i__1; ++i__) {
/*< K = LSCALE( I ) >*/
k = (integer) lscale[i__];
/*< >*/
if (k == i__) {
goto L100;
}
/*< CALL DSWAP( M, V( I, 1 ), LDV, V( K, 1 ), LDV ) >*/
dswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
/*< 100 CONTINUE >*/
L100:
;
}
/*< END IF >*/
}
/*< END IF >*/
}
/*< 110 CONTINUE >*/
L110:
/*< RETURN >*/
return 0;
/* End of DGGBAK */
/*< END >*/
} /* dggbak_ */
#ifdef __cplusplus
}
#endif
|
