/* ./src_f77/zngets.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>

/* Common Block Declarations */

struct {
    integer logfil, ndigit, mgetv0, msaupd, msaup2, msaitr, mseigt, msapps, 
	    msgets, mseupd, mnaupd, mnaup2, mnaitr, mneigh, mnapps, mngets, 
	    mneupd, mcaupd, mcaup2, mcaitr, mceigh, mcapps, mcgets, mceupd;
} debug_ZNGETS;

#define debug_1 debug_ZNGETS

struct {
    integer nopx, nbx, nrorth, nitref, nrstrt;
    real tsaupd, tsaup2, tsaitr, tseigt, tsgets, tsapps, tsconv, tnaupd, 
	    tnaup2, tnaitr, tneigh, tngets, tnapps, tnconv, tcaupd, tcaup2, 
	    tcaitr, tceigh, tcgets, tcapps, tcconv, tmvopx, tmvbx, tgetv0, 
	    titref, trvec;
} timing_ZNGETS;

#define timing_1 timing_ZNGETS

/* Table of constant values */

static logical c_true = TRUE_;
static integer c__1 = 1;

/* \BeginDoc */

/* \Name: zngets */

/* \Description: */
/*  Given the eigenvalues of the upper Hessenberg matrix H, */
/*  computes the NP shifts AMU that are zeros of the polynomial of */
/*  degree NP which filters out components of the unwanted eigenvectors */
/*  corresponding to the AMU's based on some given criteria. */

/*  NOTE: call this even in the case of user specified shifts in order */
/*  to sort the eigenvalues, and error bounds of H for later use. */

/* \Usage: */
/*  call zngets */
/*      ( ISHIFT, WHICH, KEV, NP, RITZ, BOUNDS ) */

/* \Arguments */
/*  ISHIFT  Integer.  (INPUT) */
/*          Method for selecting the implicit shifts at each iteration. */
/*          ISHIFT = 0: user specified shifts */
/*          ISHIFT = 1: exact shift with respect to the matrix H. */

/*  WHICH   Character*2.  (INPUT) */
/*          Shift selection criteria. */
/*          'LM' -> want the KEV eigenvalues of largest magnitude. */
/*          'SM' -> want the KEV eigenvalues of smallest magnitude. */
/*          'LR' -> want the KEV eigenvalues of largest REAL part. */
/*          'SR' -> want the KEV eigenvalues of smallest REAL part. */
/*          'LI' -> want the KEV eigenvalues of largest imaginary part. */
/*          'SI' -> want the KEV eigenvalues of smallest imaginary part. */

/*  KEV     Integer.  (INPUT) */
/*          The number of desired eigenvalues. */

/*  NP      Integer.  (INPUT) */
/*          The number of shifts to compute. */

/*  RITZ    Complex*16 array of length KEV+NP.  (INPUT/OUTPUT) */
/*          On INPUT, RITZ contains the the eigenvalues of H. */
/*          On OUTPUT, RITZ are sorted so that the unwanted */
/*          eigenvalues are in the first NP locations and the wanted */
/*          portion is in the last KEV locations.  When exact shifts are */
/*          selected, the unwanted part corresponds to the shifts to */
/*          be applied. Also, if ISHIFT .eq. 1, the unwanted eigenvalues */
/*          are further sorted so that the ones with largest Ritz values */
/*          are first. */

/*  BOUNDS  Complex*16 array of length KEV+NP.  (INPUT/OUTPUT) */
/*          Error bounds corresponding to the ordering in RITZ. */



/* \EndDoc */

/* ----------------------------------------------------------------------- */

/* \BeginLib */

/* \Local variables: */
/*     xxxxxx  Complex*16 */

/* \Routines called: */
/*     zsortc  ARPACK sorting routine. */
/*     ivout   ARPACK utility routine that prints integers. */
/*     second  ARPACK utility routine for timing. */
/*     zvout   ARPACK utility routine that prints vectors. */

/* \Author */
/*     Danny Sorensen               Phuong Vu */
/*     Richard Lehoucq              CRPC / Rice University */
/*     Dept. of Computational &     Houston, Texas */
/*     Applied Mathematics */
/*     Rice University */
/*     Houston, Texas */

/* \SCCS Information: @(#) */
/* FILE: ngets.F   SID: 2.2   DATE OF SID: 4/20/96   RELEASE: 2 */

/* \Remarks */
/*     1. This routine does not keep complex conjugate pairs of */
/*        eigenvalues together. */

/* \EndLib */

/* ----------------------------------------------------------------------- */

/* Subroutine */ int zngets_(integer *ishift, char *which, integer *kev, 
	integer *np, doublecomplex *ritz, doublecomplex *bounds, ftnlen 
	which_len)
{
    /* System generated locals */
    integer i__1;

    /* Local variables */
    static real t0, t1;
    extern /* Subroutine */ int ivout_(integer *, integer *, integer *, 
	    integer *, char *, ftnlen), zvout_(integer *, integer *, 
	    doublecomplex *, integer *, char *, ftnlen), second_(real *);
    static integer msglvl;
    extern /* Subroutine */ int zsortc_(char *, logical *, integer *, 
	    doublecomplex *, doublecomplex *, ftnlen);


/*     %----------------------------------------------------% */
/*     | Include files for debugging and timing information | */
/*     %----------------------------------------------------% */


/* \SCCS Information: @(#) */
/* FILE: debug.h   SID: 2.3   DATE OF SID: 11/16/95   RELEASE: 2 */

/*     %---------------------------------% */
/*     | See debug.doc for documentation | */
/*     %---------------------------------% */

/*     %------------------% */
/*     | Scalar Arguments | */
/*     %------------------% */

/*     %--------------------------------% */
/*     | See stat.doc for documentation | */
/*     %--------------------------------% */

/* \SCCS Information: @(#) */
/* FILE: stat.h   SID: 2.2   DATE OF SID: 11/16/95   RELEASE: 2 */



/*     %-----------------% */
/*     | Array Arguments | */
/*     %-----------------% */


/*     %------------% */
/*     | Parameters | */
/*     %------------% */


/*     %---------------% */
/*     | Local Scalars | */
/*     %---------------% */


/*     %----------------------% */
/*     | External Subroutines | */
/*     %----------------------% */


/*     %-----------------------% */
/*     | Executable Statements | */
/*     %-----------------------% */

/*     %-------------------------------% */
/*     | Initialize timing statistics  | */
/*     | & message level for debugging | */
/*     %-------------------------------% */

    /* Parameter adjustments */
    --bounds;
    --ritz;

    /* Function Body */
    second_(&t0);
    msglvl = debug_1.mcgets;

    i__1 = *kev + *np;
    zsortc_(which, &c_true, &i__1, &ritz[1], &bounds[1], (ftnlen)2);

    if (*ishift == 1) {

/*        %-------------------------------------------------------% */
/*        | Sort the unwanted Ritz values used as shifts so that  | */
/*        | the ones with largest Ritz estimates are first        | */
/*        | This will tend to minimize the effects of the         | */
/*        | forward instability of the iteration when the shifts  | */
/*        | are applied in subroutine znapps.                     | */
/*        | Be careful and use 'SM' since we want to sort BOUNDS! | */
/*        %-------------------------------------------------------% */

	zsortc_("SM", &c_true, np, &bounds[1], &ritz[1], (ftnlen)2);

    }

    second_(&t1);
    timing_1.tcgets += t1 - t0;

    if (msglvl > 0) {
	ivout_(&debug_1.logfil, &c__1, kev, &debug_1.ndigit, "_ngets: KEV is",
		 (ftnlen)14);
	ivout_(&debug_1.logfil, &c__1, np, &debug_1.ndigit, "_ngets: NP is", (
		ftnlen)13);
	i__1 = *kev + *np;
	zvout_(&debug_1.logfil, &i__1, &ritz[1], &debug_1.ndigit, "_ngets: E"
		"igenvalues of current H matrix ", (ftnlen)40);
	i__1 = *kev + *np;
	zvout_(&debug_1.logfil, &i__1, &bounds[1], &debug_1.ndigit, "_ngets:"
		" Ritz estimates of the current KEV+NP Ritz values", (ftnlen)
		56);
    }

    return 0;

/*     %---------------% */
/*     | End of zngets | */
/*     %---------------% */

} /* zngets_ */

