ilazlr.c

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/* ilazlr.f -- translated by f2c (version 20061008).
   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"
#include "blaswrap.h"

integer ilazlr_(integer *m, integer *n, doublecomplex *a, integer *lda)
{
    /* System generated locals */
    integer a_dim1, a_offset, ret_val, i__1, i__2;

    /* Local variables */
    integer i__, j;


/*  -- LAPACK auxiliary routine (version 3.2.1)                        -- */

/*  -- April 2009                                                      -- */

/*  -- LAPACK is a software package provided by Univ. of Tennessee,    -- */
/*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

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

/*  ILAZLR scans A for its last non-zero row. */

/*  Arguments */
/*  ========= */

/*  M       (input) INTEGER */
/*          The number of rows of the matrix A. */

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

/*  A       (input) COMPLEX*16 array, dimension (LDA,N) */
/*          The m by n matrix A. */

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

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Quick test for the common case where one corner is non-zero. */
    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;

    /* Function Body */
    if (*m == 0) {
        ret_val = *m;
    } else /* if(complicated condition) */ {
        i__1 = *m + a_dim1;
        i__2 = *m + *n * a_dim1;
        if (a[i__1].r != 0. || a[i__1].i != 0. || (a[i__2].r != 0. || a[i__2]
                .i != 0.)) {
            ret_val = *m;
        } else {
/*     Scan up each column tracking the last zero row seen. */
            ret_val = 0;
            i__1 = *n;
            for (j = 1; j <= i__1; ++j) {
                for (i__ = *m; i__ >= 1; --i__) {
                    i__2 = i__ + j * a_dim1;
                    if (a[i__2].r != 0. || a[i__2].i != 0.) {
                        break;
                    }
                }
                ret_val = max(ret_val,i__);
            }
        }
    }
    return ret_val;
} /* ilazlr_ */