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

/* Subroutine */ int cgesc2_(integer *n, complex *a, integer *lda, complex *
	rhs, integer *ipiv, integer *jpiv, real *scale)
{
/*  -- LAPACK auxiliary routine (version 3.1) --   
       Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..   
       November 2006   


    Purpose   
    =======   

    CGESC2 solves a system of linear equations   

              A * X = scale* RHS   

    with a general N-by-N matrix A using the LU factorization with   
    complete pivoting computed by CGETC2.   


    Arguments   
    =========   

    N       (input) INTEGER   
            The number of columns of the matrix A.   

    A       (input) COMPLEX array, dimension (LDA, N)   
            On entry, the  LU part of the factorization of the n-by-n   
            matrix A computed by CGETC2:  A = P * L * U * Q   

    LDA     (input) INTEGER   
            The leading dimension of the array A.  LDA >= max(1, N).   

    RHS     (input/output) COMPLEX array, dimension N.   
            On entry, the right hand side vector b.   
            On exit, the solution vector X.   

    IPIV    (input) INTEGER array, dimension (N).   
            The pivot indices; for 1 <= i <= N, row i of the   
            matrix has been interchanged with row IPIV(i).   

    JPIV    (input) INTEGER array, dimension (N).   
            The pivot indices; for 1 <= j <= N, column j of the   
            matrix has been interchanged with column JPIV(j).   

    SCALE    (output) REAL   
             On exit, SCALE contains the scale factor. SCALE is chosen   
             0 <= SCALE <= 1 to prevent owerflow in the solution.   

    Further Details   
    ===============   

    Based on contributions by   
       Bo Kagstrom and Peter Poromaa, Department of Computing Science,   
       Umea University, S-901 87 Umea, Sweden.   

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


       Set constant to control overflow   

       Parameter adjustments */
    /* Table of constant values */
    static integer c__1 = 1;
    static complex c_b13 = {1.f,0.f};
    static integer c_n1 = -1;
    
    /* System generated locals */
    integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5, i__6;
    real r__1;
    complex q__1, q__2, q__3;
    /* Builtin functions */
    double c_abs(complex *);
    void c_div(complex *, complex *, complex *);
    /* Local variables */
    static integer i__, j;
    static real eps;
    static complex temp;
    extern /* Subroutine */ int cscal_(integer *, complex *, complex *, 
	    integer *), slabad_(real *, real *);
    extern integer icamax_(integer *, complex *, integer *);
    extern doublereal slamch_(char *);
    static real bignum;
    extern /* Subroutine */ int claswp_(integer *, complex *, integer *, 
	    integer *, integer *, integer *, integer *);
    static real smlnum;


    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --rhs;
    --ipiv;
    --jpiv;

    /* Function Body */
    eps = slamch_("P");
    smlnum = slamch_("S") / eps;
    bignum = 1.f / smlnum;
    slabad_(&smlnum, &bignum);

/*     Apply permutations IPIV to RHS */

    i__1 = *n - 1;
    claswp_(&c__1, &rhs[1], lda, &c__1, &i__1, &ipiv[1], &c__1);

/*     Solve for L part */

    i__1 = *n - 1;
    for (i__ = 1; i__ <= i__1; ++i__) {
	i__2 = *n;
	for (j = i__ + 1; j <= i__2; ++j) {
	    i__3 = j;
	    i__4 = j;
	    i__5 = j + i__ * a_dim1;
	    i__6 = i__;
	    q__2.r = a[i__5].r * rhs[i__6].r - a[i__5].i * rhs[i__6].i, 
		    q__2.i = a[i__5].r * rhs[i__6].i + a[i__5].i * rhs[i__6]
		    .r;
	    q__1.r = rhs[i__4].r - q__2.r, q__1.i = rhs[i__4].i - q__2.i;
	    rhs[i__3].r = q__1.r, rhs[i__3].i = q__1.i;
/* L10: */
	}
/* L20: */
    }

/*     Solve for U part */

    *scale = 1.f;

/*     Check for scaling */

    i__ = icamax_(n, &rhs[1], &c__1);
    if (smlnum * 2.f * c_abs(&rhs[i__]) > c_abs(&a[*n + *n * a_dim1])) {
	r__1 = c_abs(&rhs[i__]);
	q__1.r = .5f / r__1, q__1.i = 0.f / r__1;
	temp.r = q__1.r, temp.i = q__1.i;
	cscal_(n, &temp, &rhs[1], &c__1);
	*scale *= temp.r;
    }
    for (i__ = *n; i__ >= 1; --i__) {
	c_div(&q__1, &c_b13, &a[i__ + i__ * a_dim1]);
	temp.r = q__1.r, temp.i = q__1.i;
	i__1 = i__;
	i__2 = i__;
	q__1.r = rhs[i__2].r * temp.r - rhs[i__2].i * temp.i, q__1.i = rhs[
		i__2].r * temp.i + rhs[i__2].i * temp.r;
	rhs[i__1].r = q__1.r, rhs[i__1].i = q__1.i;
	i__1 = *n;
	for (j = i__ + 1; j <= i__1; ++j) {
	    i__2 = i__;
	    i__3 = i__;
	    i__4 = j;
	    i__5 = i__ + j * a_dim1;
	    q__3.r = a[i__5].r * temp.r - a[i__5].i * temp.i, q__3.i = a[i__5]
		    .r * temp.i + a[i__5].i * temp.r;
	    q__2.r = rhs[i__4].r * q__3.r - rhs[i__4].i * q__3.i, q__2.i = 
		    rhs[i__4].r * q__3.i + rhs[i__4].i * q__3.r;
	    q__1.r = rhs[i__3].r - q__2.r, q__1.i = rhs[i__3].i - q__2.i;
	    rhs[i__2].r = q__1.r, rhs[i__2].i = q__1.i;
/* L30: */
	}
/* L40: */
    }

/*     Apply permutations JPIV to the solution (RHS) */

    i__1 = *n - 1;
    claswp_(&c__1, &rhs[1], lda, &c__1, &i__1, &jpiv[1], &c_n1);
    return 0;

/*     End of CGESC2 */

} /* cgesc2_ */