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/*! @file ilu_zcopy_to_ucol.c
* \brief Copy a computed column of U to the compressed data structure
* and drop some small entries
*
* <pre>
* -- SuperLU routine (version 4.1) --
* Lawrence Berkeley National Laboratory
* November, 2010
* </pre>
*/
#include "slu_zdefs.h"
#ifdef DEBUG
int num_drop_U;
#endif
extern void zcopy_(int *, doublecomplex [], int *, doublecomplex [], int *);
#if 0
static doublecomplex *A; /* used in _compare_ only */
static int _compare_(const void *a, const void *b)
{
register int *x = (int *)a, *y = (int *)b;
register double xx = z_abs1(&A[*x]), yy = z_abs1(&A[*y]);
if (xx > yy) return -1;
else if (xx < yy) return 1;
else return 0;
}
#endif
int
ilu_zcopy_to_ucol(
int jcol, /* in */
int nseg, /* in */
int *segrep, /* in */
int *repfnz, /* in */
int *perm_r, /* in */
doublecomplex *dense, /* modified - reset to zero on return */
int drop_rule,/* in */
milu_t milu, /* in */
double drop_tol, /* in */
int quota, /* maximum nonzero entries allowed */
doublecomplex *sum, /* out - the sum of dropped entries */
int *nnzUj, /* in - out */
GlobalLU_t *Glu, /* modified */
double *work /* working space with minimum size n,
* used by the second dropping rule */
)
{
/*
* Gather from SPA dense[*] to global ucol[*].
*/
int ksub, krep, ksupno;
int i, k, kfnz, segsze;
int fsupc, isub, irow;
int jsupno, nextu;
int new_next, mem_error;
int *xsup, *supno;
int *lsub, *xlsub;
doublecomplex *ucol;
int *usub, *xusub;
int nzumax;
int m; /* number of entries in the nonzero U-segments */
register double d_max = 0.0, d_min = 1.0 / dlamch_("Safe minimum");
register double tmp;
doublecomplex zero = {0.0, 0.0};
int i_1 = 1;
xsup = Glu->xsup;
supno = Glu->supno;
lsub = Glu->lsub;
xlsub = Glu->xlsub;
ucol = Glu->ucol;
usub = Glu->usub;
xusub = Glu->xusub;
nzumax = Glu->nzumax;
*sum = zero;
if (drop_rule == NODROP) {
drop_tol = -1.0, quota = Glu->n;
}
jsupno = supno[jcol];
nextu = xusub[jcol];
k = nseg - 1;
for (ksub = 0; ksub < nseg; ksub++) {
krep = segrep[k--];
ksupno = supno[krep];
if ( ksupno != jsupno ) { /* Should go into ucol[] */
kfnz = repfnz[krep];
if ( kfnz != EMPTY ) { /* Nonzero U-segment */
fsupc = xsup[ksupno];
isub = xlsub[fsupc] + kfnz - fsupc;
segsze = krep - kfnz + 1;
new_next = nextu + segsze;
while ( new_next > nzumax ) {
if ((mem_error = zLUMemXpand(jcol, nextu, UCOL, &nzumax,
Glu)) != 0)
return (mem_error);
ucol = Glu->ucol;
if ((mem_error = zLUMemXpand(jcol, nextu, USUB, &nzumax,
Glu)) != 0)
return (mem_error);
usub = Glu->usub;
lsub = Glu->lsub;
}
for (i = 0; i < segsze; i++) {
irow = lsub[isub++];
tmp = z_abs1(&dense[irow]);
/* first dropping rule */
if (quota > 0 && tmp >= drop_tol) {
if (tmp > d_max) d_max = tmp;
if (tmp < d_min) d_min = tmp;
usub[nextu] = perm_r[irow];
ucol[nextu] = dense[irow];
nextu++;
} else {
switch (milu) {
case SMILU_1:
case SMILU_2:
z_add(sum, sum, &dense[irow]);
break;
case SMILU_3:
/* *sum += fabs(dense[irow]);*/
sum->r += tmp;
break;
case SILU:
default:
break;
}
#ifdef DEBUG
num_drop_U++;
#endif
}
dense[irow] = zero;
}
}
}
} /* for each segment... */
xusub[jcol + 1] = nextu; /* Close U[*,jcol] */
m = xusub[jcol + 1] - xusub[jcol];
/* second dropping rule */
if (drop_rule & DROP_SECONDARY && m > quota) {
register double tol = d_max;
register int m0 = xusub[jcol] + m - 1;
if (quota > 0) {
if (drop_rule & DROP_INTERP) {
d_max = 1.0 / d_max; d_min = 1.0 / d_min;
tol = 1.0 / (d_max + (d_min - d_max) * quota / m);
} else {
i_1 = xusub[jcol];
for (i = 0; i < m; ++i, ++i_1) work[i] = z_abs1(&ucol[i_1]);
tol = dqselect(m, work, quota);
#if 0
A = &ucol[xusub[jcol]];
for (i = 0; i < m; i++) work[i] = i;
qsort(work, m, sizeof(int), _compare_);
tol = fabs(usub[xusub[jcol] + work[quota]]);
#endif
}
}
for (i = xusub[jcol]; i <= m0; ) {
if (z_abs1(&ucol[i]) <= tol) {
switch (milu) {
case SMILU_1:
case SMILU_2:
z_add(sum, sum, &ucol[i]);
break;
case SMILU_3:
sum->r += tmp;
break;
case SILU:
default:
break;
}
ucol[i] = ucol[m0];
usub[i] = usub[m0];
m0--;
m--;
#ifdef DEBUG
num_drop_U++;
#endif
xusub[jcol + 1]--;
continue;
}
i++;
}
}
if (milu == SMILU_2) {
sum->r = z_abs1(sum); sum->i = 0.0;
}
if (milu == SMILU_3) sum->i = 0.0;
*nnzUj += m;
return 0;
}