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-rw-r--r--src/cm/custom.c228
-rw-r--r--src/cm/custom.h9
2 files changed, 174 insertions, 63 deletions
diff --git a/src/cm/custom.c b/src/cm/custom.c
index 71d6625..0ebd708 100644
--- a/src/cm/custom.c
+++ b/src/cm/custom.c
@@ -11,6 +11,7 @@
static size_t custom_add_primes(GEN r, GEN order, GEN **primes,
size_t nprimes) {
+ debug_log("add_primes r = %Pi, nprimes = %lu", r, nprimes);
size_t nalloc = nprimes;
if (nprimes == 0) {
nalloc = 10;
@@ -46,71 +47,155 @@ static size_t custom_add_primes(GEN r, GEN order, GEN **primes,
return nprimes;
}
-static custom_quadr_t custom_quadr(GEN order) {
- pari_sp ltop = avma;
- custom_quadr_t result = {0};
+static void custom_quadr_init(custom_quadr_t *quadr, GEN order) {
+ quadr->D = gen_0;
+ quadr->p = gen_0;
+ quadr->t = gen_0;
+
+ quadr->order = order;
+ quadr->r = gen_0;
+ quadr->i = gen_0;
+ quadr->Sp = NULL;
+ quadr->nprimes = 0;
+}
- GEN r = gen_0;
- GEN *Sp;
- size_t nprimes = custom_add_primes(r, order, &Sp, 0);
+static void custom_quadr_next(custom_quadr_t *quadr) {
+ // Ok I get some state in r, i, Sp and nprimes.
+ // Here I want to check if I want to generate more primes into Sp
+ // Then continue with i
- GEN logN = ground(glog(order, BIGDEFAULTPREC));
- GEN rlog2 = sqri(mulii(r, logN));
+ GEN logN = ground(glog(quadr->order, BIGDEFAULTPREC));
+ GEN rlog2 = sqri(mulii(quadr->r, logN));
- GEN i = gen_0;
+ // When Do I want more primes? If i == imax, or nprimes == 0
+ GEN imax = int2n(quadr->nprimes);
+ if (equalii(quadr->i, imax) || quadr->nprimes == 0) {
+ quadr->nprimes = custom_add_primes(quadr->r, quadr->order, &(quadr->Sp),
+ quadr->nprimes);
+ }
while (true) {
- GEN imax = int2n(nprimes);
+ imax = int2n(quadr->nprimes);
- while (cmpii(i, imax) < 0) {
- // debug_log("i %Pi", i);
+ while (cmpii(quadr->i, imax) < 0) {
+ debug_log("i %Pi", quadr->i);
pari_sp btop = avma;
GEN pprod = gen_1;
- bits_t *ibits = bits_from_i_len(i, nprimes);
- for (size_t j = 0; j < nprimes; ++j) {
+ bits_t *ibits = bits_from_i_len(quadr->i, quadr->nprimes);
+ for (size_t j = 0; j < quadr->nprimes; ++j) {
if (GET_BIT(ibits->bits, j) == 1) {
- // debug_log("multiplying %Pi", Sp[j]);
- pprod = mulii(pprod, Sp[j]);
+ // debug_log("multiplying %Pi", quadr->Sp[j]);
+ pprod = mulii(pprod, quadr->Sp[j]);
}
}
bits_free(&ibits);
if (cmpii(pprod, rlog2) < 0 && equalii(modis(pprod, 8), stoi(5))) {
- // debug_log("candidate D = %Pi", pprod);
+ debug_log("candidate D = %Pi, rlog2 = %Pi", pprod, rlog2);
GEN x;
GEN y;
- cornacchia2(negi(pprod), order, &x, &y);
- GEN pp1 = addii(addis(order, 1), x);
- GEN pp2 = subii(addis(order, 1), x);
+ if (!cornacchia2(negi(pprod), quadr->order, &x, &y)) {
+ avma = btop;
+ quadr->i = addis(quadr->i, 1);
+ // debug_log("Cornacchia fail");
+ continue;
+ }
+ GEN pp1 = addii(addis(quadr->order, 1), x);
+ GEN pp2 = subii(addis(quadr->order, 1), x);
if (isprime(pp1)) {
- result.p = pp1;
- result.D = pprod;
- result.t = x;
- result.v = gen_0;
- gerepileall(ltop, 4, &result.p, &result.t, &result.v,
- &result.D);
- try_free(Sp);
- return result;
+ quadr->p = pp1;
+ quadr->D = pprod;
+ quadr->t = x;
+ quadr->i = addis(quadr->i, 1);
+ debug_log("good D %Pi", pprod);
+ return;
}
if (isprime(pp2)) {
- result.p = pp2;
- result.D = pprod;
- result.t = x;
- result.v = gen_0;
- gerepileall(ltop, 4, &result.p, &result.t, &result.v,
- &result.D);
- try_free(Sp);
- return result;
+ quadr->p = pp2;
+ quadr->D = pprod;
+ quadr->t = x;
+ quadr->i = addis(quadr->i, 1);
+ debug_log("good D %Pi", pprod);
+ return;
}
}
avma = btop;
- i = addis(i, 1);
+ quadr->i = addis(quadr->i, 1);
}
- r = addis(r, 1);
- nprimes = custom_add_primes(r, order, &Sp, nprimes);
+ quadr->r = addis(quadr->r, 1);
+ quadr->nprimes = custom_add_primes(quadr->r, quadr->order, &(quadr->Sp),
+ quadr->nprimes);
+ rlog2 = sqri(mulii(quadr->r, logN));
}
}
+static void custom_quadr_free(custom_quadr_t *quadr) { try_free(quadr->Sp); }
+
+/*
+static custom_quadr_t custom_quadr(GEN order) {
+ pari_sp ltop = avma;
+ custom_quadr_t result = {0};
+
+ GEN r = gen_0;
+ GEN *Sp;
+ size_t nprimes = custom_add_primes(r, order, &Sp, 0);
+
+ GEN logN = ground(glog(order, BIGDEFAULTPREC));
+ GEN rlog2 = sqri(mulii(r, logN));
+
+ GEN i = gen_0;
+
+ while (true) {
+ GEN imax = int2n(nprimes);
+
+ while (cmpii(i, imax) < 0) {
+ // debug_log("i %Pi", i);
+ pari_sp btop = avma;
+ GEN pprod = gen_1;
+ bits_t *ibits = bits_from_i_len(i, nprimes);
+ for (size_t j = 0; j < nprimes; ++j) {
+ if (GET_BIT(ibits->bits, j) == 1) {
+ // debug_log("multiplying %Pi", Sp[j]);
+ pprod = mulii(pprod, Sp[j]);
+ }
+ }
+ bits_free(&ibits);
+ if (cmpii(pprod, rlog2) < 0 && equalii(modis(pprod, 8), stoi(5))) {
+ // debug_log("candidate D = %Pi", pprod);
+ GEN x;
+ GEN y;
+ cornacchia2(negi(pprod), order, &x, &y);
+ GEN pp1 = addii(addis(order, 1), x);
+ GEN pp2 = subii(addis(order, 1), x);
+ if (isprime(pp1)) {
+ result.p = pp1;
+ result.D = pprod;
+ result.t = x;
+ gerepileall(ltop, 3, &result.p, &result.t,
+ &result.D);
+ try_free(Sp);
+ return result;
+ }
+ if (isprime(pp2)) {
+ result.p = pp2;
+ result.D = pprod;
+ result.t = x;
+ gerepileall(ltop, 3, &result.p, &result.t,
+ &result.D);
+ try_free(Sp);
+ return result;
+ }
+ }
+ avma = btop;
+ i = addis(i, 1);
+ }
+
+ r = addis(r, 1);
+ nprimes = custom_add_primes(r, order, &Sp, nprimes);
+ }
+}
+*/
+
curve_t *custom_curve() {
GEN order = strtoi(cfg->cm_order);
if (!isprime(order)) {
@@ -118,36 +203,55 @@ curve_t *custom_curve() {
return NULL;
}
- custom_quadr_t quadr = custom_quadr(order);
- debug_log("order = %Pi", order);
- debug_log("p = %Pi, t = %Pi, v = %Pi, D = %Pi, ", quadr.p, quadr.t, quadr.v,
- quadr.D);
- GEN H = polclass(quadr.D, 0, 0);
-
- debug_log("H = %Ps", H);
-
- GEN r = FpX_roots(H, quadr.p);
- debug_log("roots = %Ps", r);
-
GEN a = NULL;
GEN e = NULL;
GEN g = NULL;
- 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),
- quadr.p);
- e = ellinit(mkvec2(a, negi(a)), quadr.p, 0);
- g = genrand(e);
- GEN gmul = ellmul(e, g, order);
- if (gequal(gmul, gtovec(gen_0))) {
- debug_log("YES %Ps", e);
- break;
+ custom_quadr_t quadr;
+ custom_quadr_init(&quadr, order);
+ while (true) {
+ custom_quadr_next(&quadr);
+
+ debug_log("order = %Pi", order);
+ debug_log("p = %Pi, t = %Pi, D = %Pi, ", quadr.p, quadr.t, quadr.D);
+ GEN H = polclass(quadr.D, 0, 0);
+
+ debug_log("H = %Ps", H);
+
+ GEN r = FpX_roots(H, quadr.p);
+ debug_log("roots = %Ps", r);
+ if (gequal(r, gtovec(gen_0))) {
+ continue;
}
+
+ bool has_curve = false;
+
+ 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),
+ quadr.p);
+ e = ellinit(mkvec2(a, negi(a)), quadr.p, 0);
+ pari_CATCH(e_TYPE) { continue; }
+ pari_TRY { checkell(e); };
+ pari_ENDCATCH{};
+
+ g = genrand(e);
+ GEN gmul = ellmul(e, g, order);
+ if (ell_is_inf(gmul)) {
+ debug_log("YES %Ps", e);
+ has_curve = true;
+ break;
+ }
+ }
+
+ if (has_curve) break;
}
+ custom_quadr_free(&quadr);
+
curve_t *result = curve_new();
result->field = quadr.p;
result->a = a;
diff --git a/src/cm/custom.h b/src/cm/custom.h
index da5007a..221c8be 100644
--- a/src/cm/custom.h
+++ b/src/cm/custom.h
@@ -9,10 +9,17 @@
#include "misc/types.h"
typedef struct {
+ /* Stuff filled with custom_quadr_next. */
GEN p;
GEN t;
- GEN v;
GEN D;
+
+ /* Stuff for saving state. */
+ GEN order;
+ GEN r;
+ GEN i;
+ GEN* Sp;
+ size_t nprimes;
} custom_quadr_t;
/**
generated by cgit v1.2.3-70-g09d2 (git 2.51.2) at 2025-11-08 22:42:44 +0000