From 96946f633a839757e3a40e0f9020be722e4a0c42 Mon Sep 17 00:00:00 2001
From: Andreas Enge <andreas.enge@inria.fr>
Date: Fri, 24 Feb 2023 13:08:09 +0100
Subject: [PATCH] Correct logic in class polynomial factoring.
* lib/pari.c (mpzx_oneroot_split_mod): Make sure that factors of factors
are also read by only treating one factor per loop round.
---
lib/pari.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)
diff --git a/lib/pari.c b/lib/pari.c
index e7f7e6f..ec26772 100644
--- a/lib/pari.c
+++ b/lib/pari.c
@@ -524,7 +524,7 @@ void mpzx_oneroot_split_mod (mpz_ptr root, mpzx_srcptr f, mpz_srcptr p,
/* Compute in root a root of the polynomial f over the prime field
of characteristic p, assuming that f splits completely. */
{
- mpzx_t F, factor, factorloc;
+ mpzx_t F, factor;
mpz_t inv;
int i;
cm_timer_t clock;
@@ -548,22 +548,18 @@ void mpzx_oneroot_split_mod (mpz_ptr root, mpzx_srcptr f, mpz_srcptr p,
while (F->deg != 1) {
/* Try to read a factor of F from a checkpointing file. */
- if (tmpdir != NULL) {
- mpzx_init (factorloc, -1);
- if (cm_file_read_factor (tmpdir, factorloc, F, p)) {
- mpzx_set (F, factorloc);
- if (debug)
- cm_file_printf (" Read factor of degree %i\n", F->deg);
- }
- mpzx_clear (factorloc);
+ if (tmpdir != NULL && cm_file_read_factor (tmpdir, factor, F, p)) {
+ if (debug)
+ cm_file_printf (" Read factor of degree %i\n", factor->deg);
}
+ else {
+ /* Find a factor. */
+ mpzx_onefactor_split_mod (factor, F, p, debug);
- /* Find a smaller factor. */
- mpzx_onefactor_split_mod (factor, F, p, debug);
-
- /* Write the factor to a checkpointing file. */
- if (tmpdir != NULL)
- cm_file_write_factor (tmpdir, factor, F, p);
+ /* Write the factor to a checkpointing file. */
+ if (tmpdir != NULL)
+ cm_file_write_factor (tmpdir, factor, F, p);
+ }
/* Replace F by the factor. */
mpzx_set (F, factor);
--
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