/*  -- translated by f2c (version 20240504).
   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
*/

#include "f2c.h"

/* -----------------------------------------------------------------------   
   \BeginDoc   

   \Name: dsortc   

   \Description:   
    Sorts the complex array in XREAL and XIMAG into the order   
    specified by WHICH and optionally applies the permutation to the   
    real array Y. It is assumed that if an element of XIMAG is   
    nonzero, then its negative is also an element. In other words,   
    both members of a complex conjugate pair are to be sorted and the   
    pairs are kept adjacent to each other.   

   \Usage:   
    call dsortc   
       ( WHICH, APPLY, N, XREAL, XIMAG, Y )   

   \Arguments   
    WHICH   Character*2.  (Input)   
            'LM' -> sort XREAL,XIMAG into increasing order of magnitude.   
            'SM' -> sort XREAL,XIMAG into decreasing order of magnitude.   
            'LR' -> sort XREAL into increasing order of algebraic.   
            'SR' -> sort XREAL into decreasing order of algebraic.   
            'LI' -> sort XIMAG into increasing order of magnitude.   
            'SI' -> sort XIMAG into decreasing order of magnitude.   
            NOTE: If an element of XIMAG is non-zero, then its negative   
                  is also an element.   

    APPLY   Logical.  (Input)   
            APPLY = .TRUE.  -> apply the sorted order to array Y.   
            APPLY = .FALSE. -> do not apply the sorted order to array Y.   

    N       Integer.  (INPUT)   
            Size of the arrays.   

    XREAL,  Double precision array of length N.  (INPUT/OUTPUT)   
    XIMAG   Real and imaginary part of the array to be sorted.   

    Y       Double precision array of length N.  (INPUT/OUTPUT)   

   \EndDoc   

   -----------------------------------------------------------------------   

   \BeginLib   

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

   \Revision history:   
       xx/xx/92: Version ' 2.1'   
                 Adapted from the sort routine in LANSO.   

   \SCCS Information: @(#)   
   FILE: sortc.F   SID: 2.3   DATE OF SID: 4/20/96   RELEASE: 2   

   \EndLib   

   -----------------------------------------------------------------------   

   Subroutine */ int igraphdsortc_(char *which, logical *apply, integer *n, 
	doublereal *xreal, doublereal *ximag, doublereal *y)
{
    /* System generated locals */
    integer i__1;
    doublereal d__1, d__2;

    /* Builtin functions */
    integer s_cmp(char *, char *, ftnlen, ftnlen);

    /* Local variables */
    integer i__, j, igap;
    doublereal temp, temp1, temp2;
    extern doublereal igraphdlapy2_(doublereal *, doublereal *);


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


       %-----------------%   
       | Array Arguments |   
       %-----------------%   


       %---------------%   
       | Local Scalars |   
       %---------------%   


       %--------------------%   
       | External Functions |   
       %--------------------%   


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

    igap = *n / 2;

    if (s_cmp(which, "LM", (ftnlen)2, (ftnlen)2) == 0) {

/*        %------------------------------------------------------%   
          | Sort XREAL,XIMAG into increasing order of magnitude. |   
          %------------------------------------------------------% */

L10:
	if (igap == 0) {
	    goto L9000;
	}

	i__1 = *n - 1;
	for (i__ = igap; i__ <= i__1; ++i__) {
	    j = i__ - igap;
L20:

	    if (j < 0) {
		goto L30;
	    }

	    temp1 = igraphdlapy2_(&xreal[j], &ximag[j]);
	    temp2 = igraphdlapy2_(&xreal[j + igap], &ximag[j + igap]);

	    if (temp1 > temp2) {
		temp = xreal[j];
		xreal[j] = xreal[j + igap];
		xreal[j + igap] = temp;

		temp = ximag[j];
		ximag[j] = ximag[j + igap];
		ximag[j + igap] = temp;

		if (*apply) {
		    temp = y[j];
		    y[j] = y[j + igap];
		    y[j + igap] = temp;
		}
	    } else {
		goto L30;
	    }
	    j -= igap;
	    goto L20;
L30:
	    ;
	}
	igap /= 2;
	goto L10;

    } else if (s_cmp(which, "SM", (ftnlen)2, (ftnlen)2) == 0) {

/*        %------------------------------------------------------%   
          | Sort XREAL,XIMAG into decreasing order of magnitude. |   
          %------------------------------------------------------% */

L40:
	if (igap == 0) {
	    goto L9000;
	}

	i__1 = *n - 1;
	for (i__ = igap; i__ <= i__1; ++i__) {
	    j = i__ - igap;
L50:

	    if (j < 0) {
		goto L60;
	    }

	    temp1 = igraphdlapy2_(&xreal[j], &ximag[j]);
	    temp2 = igraphdlapy2_(&xreal[j + igap], &ximag[j + igap]);

	    if (temp1 < temp2) {
		temp = xreal[j];
		xreal[j] = xreal[j + igap];
		xreal[j + igap] = temp;

		temp = ximag[j];
		ximag[j] = ximag[j + igap];
		ximag[j + igap] = temp;

		if (*apply) {
		    temp = y[j];
		    y[j] = y[j + igap];
		    y[j + igap] = temp;
		}
	    } else {
		goto L60;
	    }
	    j -= igap;
	    goto L50;
L60:
	    ;
	}
	igap /= 2;
	goto L40;

    } else if (s_cmp(which, "LR", (ftnlen)2, (ftnlen)2) == 0) {

/*        %------------------------------------------------%   
          | Sort XREAL into increasing order of algebraic. |   
          %------------------------------------------------% */

L70:
	if (igap == 0) {
	    goto L9000;
	}

	i__1 = *n - 1;
	for (i__ = igap; i__ <= i__1; ++i__) {
	    j = i__ - igap;
L80:

	    if (j < 0) {
		goto L90;
	    }

	    if (xreal[j] > xreal[j + igap]) {
		temp = xreal[j];
		xreal[j] = xreal[j + igap];
		xreal[j + igap] = temp;

		temp = ximag[j];
		ximag[j] = ximag[j + igap];
		ximag[j + igap] = temp;

		if (*apply) {
		    temp = y[j];
		    y[j] = y[j + igap];
		    y[j + igap] = temp;
		}
	    } else {
		goto L90;
	    }
	    j -= igap;
	    goto L80;
L90:
	    ;
	}
	igap /= 2;
	goto L70;

    } else if (s_cmp(which, "SR", (ftnlen)2, (ftnlen)2) == 0) {

/*        %------------------------------------------------%   
          | Sort XREAL into decreasing order of algebraic. |   
          %------------------------------------------------% */

L100:
	if (igap == 0) {
	    goto L9000;
	}
	i__1 = *n - 1;
	for (i__ = igap; i__ <= i__1; ++i__) {
	    j = i__ - igap;
L110:

	    if (j < 0) {
		goto L120;
	    }

	    if (xreal[j] < xreal[j + igap]) {
		temp = xreal[j];
		xreal[j] = xreal[j + igap];
		xreal[j + igap] = temp;

		temp = ximag[j];
		ximag[j] = ximag[j + igap];
		ximag[j + igap] = temp;

		if (*apply) {
		    temp = y[j];
		    y[j] = y[j + igap];
		    y[j + igap] = temp;
		}
	    } else {
		goto L120;
	    }
	    j -= igap;
	    goto L110;
L120:
	    ;
	}
	igap /= 2;
	goto L100;

    } else if (s_cmp(which, "LI", (ftnlen)2, (ftnlen)2) == 0) {

/*        %------------------------------------------------%   
          | Sort XIMAG into increasing order of magnitude. |   
          %------------------------------------------------% */

L130:
	if (igap == 0) {
	    goto L9000;
	}
	i__1 = *n - 1;
	for (i__ = igap; i__ <= i__1; ++i__) {
	    j = i__ - igap;
L140:

	    if (j < 0) {
		goto L150;
	    }

	    if ((d__1 = ximag[j], abs(d__1)) > (d__2 = ximag[j + igap], abs(
		    d__2))) {
		temp = xreal[j];
		xreal[j] = xreal[j + igap];
		xreal[j + igap] = temp;

		temp = ximag[j];
		ximag[j] = ximag[j + igap];
		ximag[j + igap] = temp;

		if (*apply) {
		    temp = y[j];
		    y[j] = y[j + igap];
		    y[j + igap] = temp;
		}
	    } else {
		goto L150;
	    }
	    j -= igap;
	    goto L140;
L150:
	    ;
	}
	igap /= 2;
	goto L130;

    } else if (s_cmp(which, "SI", (ftnlen)2, (ftnlen)2) == 0) {

/*        %------------------------------------------------%   
          | Sort XIMAG into decreasing order of magnitude. |   
          %------------------------------------------------% */

L160:
	if (igap == 0) {
	    goto L9000;
	}
	i__1 = *n - 1;
	for (i__ = igap; i__ <= i__1; ++i__) {
	    j = i__ - igap;
L170:

	    if (j < 0) {
		goto L180;
	    }

	    if ((d__1 = ximag[j], abs(d__1)) < (d__2 = ximag[j + igap], abs(
		    d__2))) {
		temp = xreal[j];
		xreal[j] = xreal[j + igap];
		xreal[j + igap] = temp;

		temp = ximag[j];
		ximag[j] = ximag[j + igap];
		ximag[j + igap] = temp;

		if (*apply) {
		    temp = y[j];
		    y[j] = y[j + igap];
		    y[j + igap] = temp;
		}
	    } else {
		goto L180;
	    }
	    j -= igap;
	    goto L170;
L180:
	    ;
	}
	igap /= 2;
	goto L160;
    }

L9000:
    return 0;

/*     %---------------%   
       | End of dsortc |   
       %---------------% */

} /* igraphdsortc_ */

