#include "blaswrap.h"
#include "f2c.h"

/* Subroutine */ int dlamrg_(integer *n1, integer *n2, doublereal *a, integer 
	*dtrd1, integer *dtrd2, integer *index)
{
/*  -- 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   


    Purpose   
    =======   

    DLAMRG will create a permutation list which will merge the elements   
    of A (which is composed of two independently sorted sets) into a   
    single set which is sorted in ascending order.   

    Arguments   
    =========   

    N1     (input) INTEGER   
    N2     (input) INTEGER   
           These arguements contain the respective lengths of the two   
           sorted lists to be merged.   

    A      (input) DOUBLE PRECISION array, dimension (N1+N2)   
           The first N1 elements of A contain a list of numbers which   
           are sorted in either ascending or descending order.  Likewise   
           for the final N2 elements.   

    DTRD1  (input) INTEGER   
    DTRD2  (input) INTEGER   
           These are the strides to be taken through the array A.   
           Allowable strides are 1 and -1.  They indicate whether a   
           subset of A is sorted in ascending (DTRDx = 1) or descending   
           (DTRDx = -1) order.   

    INDEX  (output) INTEGER array, dimension (N1+N2)   
           On exit this array will contain a permutation such that   
           if B( I ) = A( INDEX( I ) ) for I=1,N1+N2, then B will be   
           sorted in ascending order.   

    =====================================================================   


       Parameter adjustments */
    /* System generated locals */
    integer i__1;
    /* Local variables */
    static integer i__, ind1, ind2, n1sv, n2sv;

    --index;
    --a;

    /* Function Body */
    n1sv = *n1;
    n2sv = *n2;
    if (*dtrd1 > 0) {
	ind1 = 1;
    } else {
	ind1 = *n1;
    }
    if (*dtrd2 > 0) {
	ind2 = *n1 + 1;
    } else {
	ind2 = *n1 + *n2;
    }
    i__ = 1;
/*     while ( (N1SV > 0) & (N2SV > 0) ) */
L10:
    if (n1sv > 0 && n2sv > 0) {
	if (a[ind1] <= a[ind2]) {
	    index[i__] = ind1;
	    ++i__;
	    ind1 += *dtrd1;
	    --n1sv;
	} else {
	    index[i__] = ind2;
	    ++i__;
	    ind2 += *dtrd2;
	    --n2sv;
	}
	goto L10;
    }
/*     end while */
    if (n1sv == 0) {
	i__1 = n2sv;
	for (n1sv = 1; n1sv <= i__1; ++n1sv) {
	    index[i__] = ind2;
	    ++i__;
	    ind2 += *dtrd2;
/* L20: */
	}
    } else {
/*     N2SV .EQ. 0 */
	i__1 = n1sv;
	for (n2sv = 1; n2sv <= i__1; ++n2sv) {
	    index[i__] = ind1;
	    ++i__;
	    ind1 += *dtrd1;
/* L30: */
	}
    }

    return 0;

/*     End of DLAMRG */

} /* dlamrg_ */

