/* The implementation is based on Section 5.2 of Michael Karr,
* "Affine Relationships Among Variables of a Program",
* except that the echelon form we use starts from the last column
* and that we are dealing with integer coefficients.
*/
static struct isl_basic_set *affine_hull(
struct isl_basic_set *bset1, struct isl_basic_set *bset2)
{
unsigned total;
int col;
int row;
if (!bset1 || !bset2)
goto error;
total = 1 + isl_basic_set_n_dim(bset1);
row = 0;
for (col = total-1; col >= 0; --col) {
int is_zero1 = row >= bset1->n_eq ||
isl_int_is_zero(bset1->eq[row][col]);
int is_zero2 = row >= bset2->n_eq ||
isl_int_is_zero(bset2->eq[row][col]);
if (!is_zero1 && !is_zero2) {
set_common_multiple(bset1, bset2, row, col);
++row;
} else if (!is_zero1 && is_zero2) {
construct_column(bset1, bset2, row, col);
} else if (is_zero1 && !is_zero2) {
construct_column(bset2, bset1, row, col);
} else {
if (transform_column(bset1, bset2, row, col))
--row;
}
}
isl_assert(bset1->ctx, row == bset1->n_eq, goto error);
isl_basic_set_free(bset2);
bset1 = isl_basic_set_normalize_constraints(bset1);
return bset1;
error:
isl_basic_set_free(bset1);
isl_basic_set_free(bset2);
return NULL;
}
size_t TRILINOS_KLU_kernel /* final size of LU on output */
(
/* input, not modified */
Int n, /* A is n-by-n */
Int Ap [ ], /* size n+1, column pointers for A */
Int Ai [ ], /* size nz = Ap [n], row indices for A */
Entry Ax [ ], /* size nz, values of A */
Int Q [ ], /* size n, optional input permutation */
size_t lusize, /* initial size of LU on input */
/* output, not defined on input */
Int Pinv [ ], /* size n, inverse row permutation, where Pinv [i] = k if
* row i is the kth pivot row */
Int P [ ], /* size n, row permutation, where P [k] = i if row i is the
* kth pivot row. */
Unit **p_LU, /* LU array, size lusize on input */
Entry Udiag [ ], /* size n, diagonal of U */
Int Llen [ ], /* size n, column length of L */
Int Ulen [ ], /* size n, column length of U */
Int Lip [ ], /* size n, column pointers for L */
Int Uip [ ], /* size n, column pointers for U */
Int *lnz, /* size of L*/
Int *unz, /* size of U*/
/* workspace, not defined on input */
Entry X [ ], /* size n, undefined on input, zero on output */
/* workspace, not defined on input or output */
Int Stack [ ], /* size n */
Int Flag [ ], /* size n */
Int Ap_pos [ ], /* size n */
/* other workspace: */
Int Lpend [ ], /* size n workspace, for pruning only */
/* inputs, not modified on output */
Int k1, /* the block of A is from k1 to k2-1 */
Int PSinv [ ], /* inverse of P from symbolic factorization */
double Rs [ ], /* scale factors for A */
/* inputs, modified on output */
Int Offp [ ], /* off-diagonal matrix (modified by this routine) */
Int Offi [ ],
Entry Offx [ ],
/* --------------- */
TRILINOS_KLU_common *Common
)
{
Entry pivot ;
double abs_pivot, xsize, nunits, tol, memgrow ;
Entry *Ux ;
Int *Li, *Ui ;
Unit *LU ; /* LU factors (pattern and values) */
Int k, p, i, j, pivrow, kbar, diagrow, firstrow, lup, top, scale, len ;
size_t newlusize ;
#ifndef NDEBUG
Entry *Lx ;
#endif
ASSERT (Common != NULL) ;
scale = Common->scale ;
tol = Common->tol ;
memgrow = Common->memgrow ;
*lnz = 0 ;
*unz = 0 ;
/* ---------------------------------------------------------------------- */
/* get initial Li, Lx, Ui, and Ux */
/* ---------------------------------------------------------------------- */
PRINTF (("input: lusize %d \n", lusize)) ;
ASSERT (lusize > 0) ;
LU = *p_LU ;
/* ---------------------------------------------------------------------- */
/* initializations */
/* ---------------------------------------------------------------------- */
firstrow = 0 ;
lup = 0 ;
for (k = 0 ; k < n ; k++)
{
/* X [k] = 0 ; */
CLEAR (X [k]) ;
Flag [k] = EMPTY ;
Lpend [k] = EMPTY ; /* flag k as not pruned */
}
/* ---------------------------------------------------------------------- */
/* mark all rows as non-pivotal and determine initial diagonal mapping */
/* ---------------------------------------------------------------------- */
/* PSinv does the symmetric permutation, so don't do it here */
for (k = 0 ; k < n ; k++)
{
P [k] = k ;
Pinv [k] = FLIP (k) ; /* mark all rows as non-pivotal */
}
/* initialize the construction of the off-diagonal matrix */
Offp [0] = 0 ;
/* P [k] = row means that UNFLIP (Pinv [row]) = k, and visa versa.
* If row is pivotal, then Pinv [row] >= 0. A row is initially "flipped"
* (Pinv [k] < EMPTY), and then marked "unflipped" when it becomes
* pivotal. */
#ifndef NDEBUG
for (k = 0 ; k < n ; k++)
{
PRINTF (("Initial P [%d] = %d\n", k, P [k])) ;
}
#endif
/* ---------------------------------------------------------------------- */
/* factorize */
/* ---------------------------------------------------------------------- */
for (k = 0 ; k < n ; k++)
{
PRINTF (("\n\n==================================== k: %d\n", k)) ;
/* ------------------------------------------------------------------ */
/* determine if LU factors have grown too big */
/* ------------------------------------------------------------------ */
/* (n - k) entries for L and k entries for U */
nunits = DUNITS (Int, n - k) + DUNITS (Int, k) +
DUNITS (Entry, n - k) + DUNITS (Entry, k) ;
/* LU can grow by at most 'nunits' entries if the column is dense */
PRINTF (("lup %d lusize %g lup+nunits: %g\n", lup, (double) lusize,
lup+nunits));
xsize = ((double) lup) + nunits ;
if (xsize > (double) lusize)
{
/* check here how much to grow */
xsize = (memgrow * ((double) lusize) + 4*n + 1) ;
if (INT_OVERFLOW (xsize))
{
PRINTF (("Matrix is too large (Int overflow)\n")) ;
Common->status = TRILINOS_KLU_TOO_LARGE ;
return (lusize) ;
}
newlusize = memgrow * lusize + 2*n + 1 ;
/* Future work: retry mechanism in case of malloc failure */
LU = (Unit*) TRILINOS_KLU_realloc (newlusize, lusize, sizeof (Unit), LU, Common) ;
Common->nrealloc++ ;
*p_LU = LU ;
if (Common->status == TRILINOS_KLU_OUT_OF_MEMORY)
{
PRINTF (("Matrix is too large (LU)\n")) ;
return (lusize) ;
}
lusize = newlusize ;
PRINTF (("inc LU to %d done\n", lusize)) ;
}
/* ------------------------------------------------------------------ */
/* start the kth column of L and U */
/* ------------------------------------------------------------------ */
Lip [k] = lup ;
/* ------------------------------------------------------------------ */
/* compute the nonzero pattern of the kth column of L and U */
/* ------------------------------------------------------------------ */
#ifndef NDEBUG
for (i = 0 ; i < n ; i++)
{
ASSERT (Flag [i] < k) ;
/* ASSERT (X [i] == 0) ; */
ASSERT (IS_ZERO (X [i])) ;
}
#endif
top = lsolve_symbolic (n, k, Ap, Ai, Q, Pinv, Stack, Flag,
Lpend, Ap_pos, LU, lup, Llen, Lip, k1, PSinv) ;
#ifndef NDEBUG
PRINTF (("--- in U:\n")) ;
for (p = top ; p < n ; p++)
{
PRINTF (("pattern of X for U: %d : %d pivot row: %d\n",
p, Stack [p], Pinv [Stack [p]])) ;
ASSERT (Flag [Stack [p]] == k) ;
}
PRINTF (("--- in L:\n")) ;
Li = (Int *) (LU + Lip [k]);
for (p = 0 ; p < Llen [k] ; p++)
{
PRINTF (("pattern of X in L: %d : %d pivot row: %d\n",
p, Li [p], Pinv [Li [p]])) ;
ASSERT (Flag [Li [p]] == k) ;
}
p = 0 ;
for (i = 0 ; i < n ; i++)
{
ASSERT (Flag [i] <= k) ;
if (Flag [i] == k) p++ ;
}
#endif
/* ------------------------------------------------------------------ */
/* get the column of the matrix to factorize and scatter into X */
/* ------------------------------------------------------------------ */
construct_column (k, Ap, Ai, Ax, Q, X,
k1, PSinv, Rs, scale, Offp, Offi, Offx) ;
/* ------------------------------------------------------------------ */
/* compute the numerical values of the kth column (s = L \ A (:,k)) */
/* ------------------------------------------------------------------ */
lsolve_numeric (Pinv, LU, Stack, Lip, top, n, Llen, X) ;
#ifndef NDEBUG
for (p = top ; p < n ; p++)
{
PRINTF (("X for U %d : ", Stack [p])) ;
PRINT_ENTRY (X [Stack [p]]) ;
}
Li = (Int *) (LU + Lip [k]) ;
for (p = 0 ; p < Llen [k] ; p++)
{
PRINTF (("X for L %d : ", Li [p])) ;
PRINT_ENTRY (X [Li [p]]) ;
}
#endif
/* ------------------------------------------------------------------ */
/* partial pivoting with diagonal preference */
/* ------------------------------------------------------------------ */
/* determine what the "diagonal" is */
diagrow = P [k] ; /* might already be pivotal */
PRINTF (("k %d, diagrow = %d, UNFLIP (diagrow) = %d\n",
k, diagrow, UNFLIP (diagrow))) ;
/* find a pivot and scale the pivot column */
if (!lpivot (diagrow, &pivrow, &pivot, &abs_pivot, tol, X, LU, Lip,
Llen, k, n, Pinv, &firstrow, Common))
{
/* matrix is structurally or numerically singular */
Common->status = TRILINOS_KLU_SINGULAR ;
if (Common->numerical_rank == EMPTY)
{
Common->numerical_rank = k+k1 ;
Common->singular_col = Q [k+k1] ;
}
if (Common->halt_if_singular)
{
/* do not continue the factorization */
return (lusize) ;
}
}
/* we now have a valid pivot row, even if the column has NaN's or
* has no entries on or below the diagonal at all. */
PRINTF (("\nk %d : Pivot row %d : ", k, pivrow)) ;
PRINT_ENTRY (pivot) ;
ASSERT (pivrow >= 0 && pivrow < n) ;
ASSERT (Pinv [pivrow] < 0) ;
/* set the Uip pointer */
Uip [k] = Lip [k] + UNITS (Int, Llen [k]) + UNITS (Entry, Llen [k]) ;
/* move the lup pointer to the position where indices of U
* should be stored */
lup += UNITS (Int, Llen [k]) + UNITS (Entry, Llen [k]) ;
Ulen [k] = n - top ;
/* extract Stack [top..n-1] to Ui and the values to Ux and clear X */
GET_POINTER (LU, Uip, Ulen, Ui, Ux, k, len) ;
for (p = top, i = 0 ; p < n ; p++, i++)
{
j = Stack [p] ;
Ui [i] = Pinv [j] ;
Ux [i] = X [j] ;
CLEAR (X [j]) ;
}
/* position the lu index at the starting point for next column */
lup += UNITS (Int, Ulen [k]) + UNITS (Entry, Ulen [k]) ;
/* U(k,k) = pivot */
Udiag [k] = pivot ;
/* ------------------------------------------------------------------ */
/* log the pivot permutation */
/* ------------------------------------------------------------------ */
ASSERT (UNFLIP (Pinv [diagrow]) < n) ;
ASSERT (P [UNFLIP (Pinv [diagrow])] == diagrow) ;
if (pivrow != diagrow)
{
/* an off-diagonal pivot has been chosen */
Common->noffdiag++ ;
PRINTF ((">>>>>>>>>>>>>>>>> pivrow %d k %d off-diagonal\n",
pivrow, k)) ;
if (Pinv [diagrow] < 0)
{
/* the former diagonal row index, diagrow, has not yet been
* chosen as a pivot row. Log this diagrow as the "diagonal"
* entry in the column kbar for which the chosen pivot row,
* pivrow, was originally logged as the "diagonal" */
kbar = FLIP (Pinv [pivrow]) ;
P [kbar] = diagrow ;
Pinv [diagrow] = FLIP (kbar) ;
}
}
P [k] = pivrow ;
Pinv [pivrow] = k ;
#ifndef NDEBUG
for (i = 0 ; i < n ; i++) { ASSERT (IS_ZERO (X [i])) ;}
GET_POINTER (LU, Uip, Ulen, Ui, Ux, k, len) ;
for (p = 0 ; p < len ; p++)
{
PRINTF (("Column %d of U: %d : ", k, Ui [p])) ;
PRINT_ENTRY (Ux [p]) ;
}
GET_POINTER (LU, Lip, Llen, Li, Lx, k, len) ;
for (p = 0 ; p < len ; p++)
{
PRINTF (("Column %d of L: %d : ", k, Li [p])) ;
PRINT_ENTRY (Lx [p]) ;
}
#endif
/* ------------------------------------------------------------------ */
/* symmetric pruning */
/* ------------------------------------------------------------------ */
prune (Lpend, Pinv, k, pivrow, LU, Uip, Lip, Ulen, Llen) ;
*lnz += Llen [k] + 1 ; /* 1 added to lnz for diagonal */
*unz += Ulen [k] + 1 ; /* 1 added to unz for diagonal */
}
/* ---------------------------------------------------------------------- */
/* finalize column pointers for L and U, and put L in the pivotal order */
/* ---------------------------------------------------------------------- */
for (p = 0 ; p < n ; p++)
{
Li = (Int *) (LU + Lip [p]) ;
for (i = 0 ; i < Llen [p] ; i++)
{
Li [i] = Pinv [Li [i]] ;
}
}
#ifndef NDEBUG
for (i = 0 ; i < n ; i++)
{
PRINTF (("P [%d] = %d Pinv [%d] = %d\n", i, P [i], i, Pinv [i])) ;
}
for (i = 0 ; i < n ; i++)
{
ASSERT (Pinv [i] >= 0 && Pinv [i] < n) ;
ASSERT (P [i] >= 0 && P [i] < n) ;
ASSERT (P [Pinv [i]] == i) ;
ASSERT (IS_ZERO (X [i])) ;
}
#endif
/* ---------------------------------------------------------------------- */
/* shrink the LU factors to just the required size */
/* ---------------------------------------------------------------------- */
newlusize = lup ;
ASSERT ((size_t) newlusize <= lusize) ;
/* this cannot fail, since the block is descreasing in size */
LU = (Unit*) TRILINOS_KLU_realloc (newlusize, lusize, sizeof (Unit), LU, Common) ;
*p_LU = LU ;
return (newlusize) ;
}
