/* ./src_f77/zggbak.f -- translated by f2c (version 20030320).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include <punc/vf2c.h>

/* Subroutine */ int zggbak_(char *job, char *side, integer *n, integer *ilo, 
	integer *ihi, doublereal *lscale, doublereal *rscale, integer *m, 
	doublecomplex *v, integer *ldv, integer *info, ftnlen job_len, ftnlen 
	side_len)
{
    /* System generated locals */
    integer v_dim1, v_offset, i__1;

    /* Local variables */
    static integer i__, k;
    extern logical lsame_(char *, char *, ftnlen, ftnlen);
    static logical leftv;
    extern /* Subroutine */ int zswap_(integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *), xerbla_(char *, integer *, ftnlen), 
	    zdscal_(integer *, doublereal *, doublecomplex *, integer *);
    static logical rightv;


/*  -- 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 .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZGGBAK forms the right or left eigenvectors of a complex generalized */
/*  eigenvalue problem A*x = lambda*B*x, by backward transformation on */
/*  the computed eigenvectors of the balanced pair of matrices output by */
/*  ZGGBAL. */

/*  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 ZGGBAL. */

/*  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 ZGGBAL. */
/*          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 ZGGBAL. */

/*  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 ZGGBAL. */

/*  M       (input) INTEGER */
/*          The number of columns of the matrix V.  M >= 0. */

/*  V       (input/output) COMPLEX*16 array, dimension (LDV,M) */
/*          On entry, the matrix of right or left eigenvectors to be */
/*          transformed, as returned by ZTGEVC. */
/*          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 .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Test the input parameters */

    /* 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", (ftnlen)1, (ftnlen)1);

    *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;
    } else if (! rightv && ! leftv) {
	*info = -2;
    } else if (*n < 0) {
	*info = -3;
    } else if (*ilo < 1) {
	*info = -4;
    } else if (*ihi < *ilo || *ihi > max(1,*n)) {
	*info = -5;
    } else if (*m < 0) {
	*info = -6;
    } else if (*ldv < max(1,*n)) {
	*info = -10;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZGGBAK", &i__1, (ftnlen)6);
	return 0;
    }

/*     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", (ftnlen)1, (ftnlen)1) || lsame_(job, "B", (ftnlen)1, 
	    (ftnlen)1)) {

/*        Backward transformation on right eigenvectors */

	if (rightv) {
	    i__1 = *ihi;
	    for (i__ = *ilo; i__ <= i__1; ++i__) {
		zdscal_(m, &rscale[i__], &v[i__ + v_dim1], ldv);
/* L10: */
	    }
	}

/*        Backward transformation on left eigenvectors */

	if (leftv) {
	    i__1 = *ihi;
	    for (i__ = *ilo; i__ <= i__1; ++i__) {
		zdscal_(m, &lscale[i__], &v[i__ + v_dim1], ldv);
/* L20: */
	    }
	}
    }

/*     Backward permutation */

L30:
    if (lsame_(job, "P", (ftnlen)1, (ftnlen)1) || lsame_(job, "B", (ftnlen)1, 
	    (ftnlen)1)) {

/*        Backward permutation on right eigenvectors */

	if (rightv) {
	    if (*ilo == 1) {
		goto L50;
	    }
	    for (i__ = *ilo - 1; i__ >= 1; --i__) {
		k = (integer) rscale[i__];
		if (k == i__) {
		    goto L40;
		}
		zswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
L40:
		;
	    }

L50:
	    if (*ihi == *n) {
		goto L70;
	    }
	    i__1 = *n;
	    for (i__ = *ihi + 1; i__ <= i__1; ++i__) {
		k = (integer) rscale[i__];
		if (k == i__) {
		    goto L60;
		}
		zswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
L60:
		;
	    }
	}

/*        Backward permutation on left eigenvectors */

L70:
	if (leftv) {
	    if (*ilo == 1) {
		goto L90;
	    }
	    for (i__ = *ilo - 1; i__ >= 1; --i__) {
		k = (integer) lscale[i__];
		if (k == i__) {
		    goto L80;
		}
		zswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
L80:
		;
	    }

L90:
	    if (*ihi == *n) {
		goto L110;
	    }
	    i__1 = *n;
	    for (i__ = *ihi + 1; i__ <= i__1; ++i__) {
		k = (integer) lscale[i__];
		if (k == i__) {
		    goto L100;
		}
		zswap_(m, &v[i__ + v_dim1], ldv, &v[k + v_dim1], ldv);
L100:
		;
	    }
	}
    }

L110:

    return 0;

/*     End of ZGGBAK */

} /* zggbak_ */

