chia-blockchain/lib/chiavdf/fast_vdf/nucomp.h

203 lines
4.8 KiB
C

/**
Copyright 2018 Chia Network Inc
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
**/
#define LOG2(X) (63 - __builtin_clzll((X)))
//using namespace std;
typedef struct qfb
{
fmpz_t a;
fmpz_t b;
fmpz_t c;
} qfb;
typedef qfb qfb_t[1];
// From Antic using Flint (works!)
void qfb_nucomp(qfb_t r, const qfb_t f, const qfb_t g, fmpz_t D, fmpz_t L)
{
fmpz_t a1, a2, c2, ca, cb, cc, k, s, sp, ss, m, t, u2, v1, v2;
if (fmpz_cmp(f->a, g->a) > 0)
{
qfb_nucomp(r, g, f, D, L);
return;
}
fmpz_init(a1); fmpz_init(a2); fmpz_init(c2);
fmpz_init(ca); fmpz_init(cb); fmpz_init(cc);
fmpz_init(k); fmpz_init(m);
fmpz_init(s); fmpz_init(sp); fmpz_init(ss);
fmpz_init(t); fmpz_init(u2); fmpz_init(v1); fmpz_init(v2);
/* nucomp calculation */
fmpz_set(a1, f->a);
fmpz_set(a2, g->a);
fmpz_set(c2, g->c);
fmpz_add(ss, f->b, g->b);
fmpz_fdiv_q_2exp(ss, ss, 1);
fmpz_sub(m, f->b, g->b);
fmpz_fdiv_q_2exp(m, m, 1);
fmpz_fdiv_r(t, a2, a1);
if (fmpz_is_zero(t))
{
fmpz_set_ui(v1, 0);
fmpz_set(sp, a1);
} else
fmpz_gcdinv(sp, v1, t, a1);
fmpz_mul(k, m, v1);
fmpz_fdiv_r(k, k, a1);
if (!fmpz_is_one(sp))
{
fmpz_xgcd(s, v2, u2, ss, sp);
fmpz_mul(k, k, u2);
fmpz_mul(t, v2, c2);
fmpz_sub(k, k, t);
if (!fmpz_is_one(s))
{
fmpz_fdiv_q(a1, a1, s);
fmpz_fdiv_q(a2, a2, s);
fmpz_mul(c2, c2, s);
}
fmpz_fdiv_r(k, k, a1);
}
if (fmpz_cmp(a1, L) < 0)
{
fmpz_mul(t, a2, k);
fmpz_mul(ca, a2, a1);
fmpz_mul_2exp(cb, t, 1);
fmpz_add(cb, cb, g->b);
fmpz_add(cc, g->b, t);
fmpz_mul(cc, cc, k);
fmpz_add(cc, cc, c2);
fmpz_fdiv_q(cc, cc, a1);
} else
{
fmpz_t m1, m2, r1, r2, co1, co2, temp;
fmpz_init(m1); fmpz_init(m2); fmpz_init(r1); fmpz_init(r2);
fmpz_init(co1); fmpz_init(co2); fmpz_init(temp);
fmpz_set(r2, a1);
fmpz_set(r1, k);
fmpz_xgcd_partial(co2, co1, r2, r1, L);
fmpz_mul(t, a2, r1);
fmpz_mul(m1, m, co1);
fmpz_add(m1, m1, t);
fmpz_tdiv_q(m1, m1, a1);
fmpz_mul(m2, ss, r1);
fmpz_mul(temp, c2, co1);
fmpz_sub(m2, m2, temp);
fmpz_tdiv_q(m2, m2, a1);
fmpz_mul(ca, r1, m1);
fmpz_mul(temp, co1, m2);
if (fmpz_sgn(co1) < 0)
fmpz_sub(ca, ca, temp);
else
fmpz_sub(ca, temp, ca);
fmpz_mul(cb, ca, co2);
fmpz_sub(cb, t, cb);
fmpz_mul_2exp(cb, cb, 1);
fmpz_fdiv_q(cb, cb, co1);
fmpz_sub(cb, cb, g->b);
fmpz_mul_2exp(temp, ca, 1);
fmpz_fdiv_r(cb, cb, temp);
fmpz_mul(cc, cb, cb);
fmpz_sub(cc, cc, D);
fmpz_fdiv_q(cc, cc, ca);
fmpz_fdiv_q_2exp(cc, cc, 2);
if (fmpz_sgn(ca) < 0)
{
fmpz_neg(ca, ca);
fmpz_neg(cc, cc);
}
fmpz_clear(m1); fmpz_clear(m2); fmpz_clear(r1); fmpz_clear(r2);
fmpz_clear(co1); fmpz_clear(co2); fmpz_clear(temp);
}
fmpz_set(r->a, ca);
fmpz_set(r->b, cb);
fmpz_set(r->c, cc);
fmpz_clear(ca); fmpz_clear(cb); fmpz_clear(cc);
fmpz_clear(k); fmpz_clear(m);
fmpz_clear(s); fmpz_clear(sp); fmpz_clear(ss);
fmpz_clear(t); fmpz_clear(u2); fmpz_clear(v1); fmpz_clear(v2);
fmpz_clear(a1); fmpz_clear(a2); fmpz_clear(c2);
}
// a = b * c
void nucomp_form(form &a, form &b, form &c, integer &D, integer &L) {
qfb fr, fr2, fr3;
fmpz_init(fr.a);
fmpz_init(fr.b);
fmpz_init(fr.c);
fmpz_init(fr2.a);
fmpz_init(fr2.b);
fmpz_init(fr2.c);
fmpz_init(fr3.a);
fmpz_init(fr3.b);
fmpz_init(fr3.c);
fmpz_set_mpz(fr2.a, b.a.impl);
fmpz_set_mpz(fr2.b, b.b.impl);
fmpz_set_mpz(fr2.c, b.c.impl);
fmpz_set_mpz(fr3.a, c.a.impl);
fmpz_set_mpz(fr3.b, c.b.impl);
fmpz_set_mpz(fr3.c, c.c.impl);
fmpz_t anticD, anticL;
fmpz_init(anticD);
fmpz_init(anticL);
fmpz_set_mpz(anticD, D.impl);
fmpz_set_mpz(anticL, L.impl);
qfb_nucomp(&fr,&fr2,&fr3,anticD,anticL);
fmpz_get_mpz(a.a.impl,fr.a);
fmpz_get_mpz(a.b.impl,fr.b);
fmpz_get_mpz(a.c.impl,fr.c);
fmpz_clear(fr.a);
fmpz_clear(fr.b);
fmpz_clear(fr.c);
fmpz_clear(fr2.a);
fmpz_clear(fr2.b);
fmpz_clear(fr2.c);
fmpz_clear(fr3.a);
fmpz_clear(fr3.b);
fmpz_clear(fr3.c);
fmpz_clear(anticD);
fmpz_clear(anticL);
}