diff options
Diffstat (limited to 'src/gen/gens.c')
| -rw-r--r-- | src/gen/gens.c | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/src/gen/gens.c b/src/gen/gens.c index 2cffbc4..e2c624e 100644 --- a/src/gen/gens.c +++ b/src/gen/gens.c @@ -40,16 +40,25 @@ GENERATOR(gens_gen_one) { CHECK(gens_check_anomalous) { if (cfg->field == FIELD_BINARY) return 1; - pari_sp ltop = avma; for (size_t i = 0; i < curve->ngens; ++i) { if (mpcmp(curve->field, curve->generators[i]->order) == 0) { - avma = ltop; return -5; } } return 1; } +GEN gens_get_embedding(GEN prime, GEN order) { + pari_sp ltop = avma; + GEN power = gen_1; + GEN pm; + do { + power = mulii(power, prime); + pm = subii(power, gen_1); + } while (!dvdii(pm, order)); + return gerepilecopy(ltop, power); +} + CHECK(gens_check_embedding) { HAS_ARG(args); if (cfg->field == FIELD_BINARY) return 1; @@ -59,13 +68,8 @@ CHECK(gens_check_embedding) { GEN mind = strtoi(min_degree); for (size_t i = 0; i < curve->ngens; ++i) { - GEN power = gen_0; - GEN pm; - do { - power = addii(power, gen_1); - GEN ppow = powii(curve->field, power); - pm = subii(ppow, gen_1); - } while (!dvdii(pm, curve->generators[i]->order)); + GEN power = + gens_get_embedding(curve->field, curve->generators[i]->order); if (mpcmp(power, mind) <= 0) { avma = ltop; |