diff options
Diffstat (limited to 'src/cm/custom.c')
| -rw-r--r-- | src/cm/custom.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/src/cm/custom.c b/src/cm/custom.c index da80329..10caff4 100644 --- a/src/cm/custom.c +++ b/src/cm/custom.c @@ -145,6 +145,7 @@ curve_t *custom_curve() { } GEN a = NULL; + GEN b = NULL; GEN e = NULL; GEN g = NULL; @@ -170,11 +171,14 @@ curve_t *custom_curve() { long rlen = glength(r); for (long i = 1; i <= rlen; ++i) { GEN root = gel(r, i); - a = Fp_div( - Fp_mul(stoi(27), root, quadr.p), - Fp_mul(stoi(4), Fp_sub(stoi(1728), root, quadr.p), quadr.p), + a = mkintmod( + Fp_div( + Fp_mul(stoi(27), root, quadr.p), + Fp_mul(stoi(4), Fp_sub(stoi(1728), root, quadr.p), quadr.p), + quadr.p), quadr.p); - e = ellinit(mkvec2(a, negi(a)), quadr.p, 0); + b = gneg(a); + e = ellinit(mkvec2(a, b), quadr.p, 0); pari_CATCH(e_TYPE) { continue; } pari_TRY { checkell(e); }; pari_ENDCATCH{}; @@ -196,7 +200,7 @@ curve_t *custom_curve() { curve_t *result = curve_new(); result->field = quadr.p; result->a = a; - result->b = negi(a); + result->b = b; result->curve = e; result->order = order; result->generators = subgroups_new(1); |