void dLCP::transfer_i_from_C_to_N (int i, void *tmpbuf)
{
{
int *C = m_C;
// remove a row/column from the factorization, and adjust the
// indexes (black magic!)
int last_idx = -1;
const int nC = m_nC;
int j = 0;
for ( ; j<nC; ++j) {
if (C[j]==nC-1) {
last_idx = j;
}
if (C[j]==i) {
dLDLTRemove (m_A,C,m_L,m_d,m_n,nC,j,m_nskip,tmpbuf);
int k;
if (last_idx == -1) {
for (k=j+1 ; k<nC; ++k) {
if (C[k]==nC-1) {
break;
}
}
dIASSERT (k < nC);
}
else {
k = last_idx;
}
C[k] = C[j];
if (j < (nC-1)) memmove (C+j,C+j+1,(nC-j-1)*sizeof(int));
break;
}
}
dIASSERT (j < nC);
swapProblem (m_A,m_x,m_b,m_w,m_lo,m_hi,m_p,m_state,m_findex,m_n,i,nC-1,m_nskip,1);
m_nN++;
m_nC = nC - 1; // nC value is outdated after this line
}
# ifdef DEBUG_LCP
checkFactorization (m_A,m_L,m_d,m_nC,m_C,m_nskip);
# endif
}
void dLCP::transfer_i_from_C_to_N (int i)
{
// remove a row/column from the factorization, and adjust the
// indexes (black magic!)
int j,k;
for (j=0; j<nC; j++) if (C[j]==i) {
dLDLTRemove (A,C,L,d,n,nC,j,nskip);
for (k=0; k<nC; k++) if (C[k]==nC-1) {
C[k] = C[j];
if (j < (nC-1)) memmove (C+j,C+j+1,(nC-j-1)*sizeof(int));
break;
}
dIASSERT (k < nC);
break;
}
dIASSERT (j < nC);
swapProblem (A,x,b,w,lo,hi,p,state,findex,n,i,nC-1,nskip,1);
nC--;
nN++;
# ifdef DEBUG_LCP
checkFactorization (A,L,d,nC,C,nskip);
# endif
}
void testLDLTRemove()
{
int i,j,r,p[MSIZE];
dReal A[MSIZE4*MSIZE], L[MSIZE4*MSIZE], d[MSIZE],
L2[MSIZE4*MSIZE], d2[MSIZE], DL2[MSIZE4*MSIZE],
Atest1[MSIZE4*MSIZE], Atest2[MSIZE4*MSIZE], diff, maxdiff;
HEADER;
// make array of A row pointers
dReal *Arows[MSIZE];
for (i=0; i<MSIZE; i++) Arows[i] = A+i*MSIZE4;
// fill permutation vector
for (i=0; i<MSIZE; i++) p[i]=i;
dMakeRandomMatrix (A,MSIZE,MSIZE,1.0);
dMultiply2 (L,A,A,MSIZE,MSIZE,MSIZE);
memcpy (A,L,MSIZE4*MSIZE*sizeof(dReal));
dFactorLDLT (L,d,MSIZE,MSIZE4);
maxdiff = 1e10;
for (r=0; r<MSIZE; r++) {
// get Atest1 = A with row/column r removed
memcpy (Atest1,A,MSIZE4*MSIZE*sizeof(dReal));
dRemoveRowCol (Atest1,MSIZE,MSIZE4,r);
// test that the row/column removal worked
int bad = 0;
for (i=0; i<MSIZE; i++) {
for (j=0; j<MSIZE; j++) {
if (i != r && j != r) {
int ii = i;
int jj = j;
if (ii >= r) ii--;
if (jj >= r) jj--;
if (A[i*MSIZE4+j] != Atest1[ii*MSIZE4+jj]) bad = 1;
}
}
}
if (bad) printf ("\trow/col removal FAILED for row %d\n",r);
// zero out last row/column of Atest1
for (i=0; i<MSIZE; i++) {
Atest1[(MSIZE-1)*MSIZE4+i] = 0;
Atest1[i*MSIZE4+MSIZE-1] = 0;
}
// get L2*D2*L2' = adjusted factorization to remove that row
memcpy (L2,L,MSIZE4*MSIZE*sizeof(dReal));
memcpy (d2,d,MSIZE*sizeof(dReal));
dLDLTRemove (/*A*/ Arows,p,L2,d2,MSIZE,MSIZE,r,MSIZE4);
// get Atest2 = L2*D2*L2'
dClearUpperTriangle (L2,MSIZE);
for (i=0; i<(MSIZE-1); i++) L2[i*MSIZE4+i] = 1.0;
for (i=0; i<MSIZE; i++) L2[(MSIZE-1)*MSIZE4+i] = 0;
d2[MSIZE-1] = 1;
dSetZero (DL2,MSIZE4*MSIZE);
for (i=0; i<(MSIZE-1); i++) {
for (j=0; j<MSIZE-1; j++) DL2[i*MSIZE4+j] = L2[i*MSIZE4+j] / d2[j];
}
dMultiply2 (Atest2,L2,DL2,MSIZE,MSIZE,MSIZE);
diff = dMaxDifference(Atest1,Atest2,MSIZE,MSIZE);
if (diff < maxdiff) maxdiff = diff;
/*
dPrintMatrix (Atest1,MSIZE,MSIZE);
printf ("\n");
dPrintMatrix (Atest2,MSIZE,MSIZE);
printf ("\n");
*/
}
printf ("\tmaximum difference = %.6e - %s\n",maxdiff,
maxdiff > tol ? "FAILED" : "passed");
}