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schoof.c
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schoof.c
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#include "schoof.h"
int main(int agrc, char** argv)
{
// Déclaration
fmpz_t q, a, b, card;
fq_ctx_t fq;
fq_t A, B, delta, tmp_fq;
// Allocation
fmpz_init(q); fmpz_init(a); fmpz_init(b); fmpz_init(card);
// Initialisation
if(fmpz_set_str(q, argv[1], 10) == -1)
{
fprintf(stderr, "q is not an integer.\n"); exit(EXIT_FAILURE);
}
if(fmpz_is_prime(q) != 1)
{
fprintf(stderr, "q is not prime.\n"); exit(EXIT_FAILURE);
}
if(fmpz_set_str(a, argv[2], 10) == -1)
{
fprintf(stderr, "a is not an integer.\n"); exit(EXIT_FAILURE);
}
if(fmpz_set_str(b, argv[3], 10) == -1)
{
fprintf(stderr, "b is not an integer.\n"); exit(EXIT_FAILURE);
}
// Transformation de a et b dans Fq
fq_ctx_init(fq, q, 1, "X");
fq_init(A, fq); fq_init(B, fq);
fq_set_fmpz(A, a, fq); fq_set_fmpz(B, b, fq);
// Libération mémoire
fmpz_clear(a); fmpz_clear(b);
// Test du discriminant pour savoir s'il s'agit bien d'une courbe elliptique
fq_init(delta, fq); fq_init(tmp_fq, fq);
fq_sqr(tmp_fq, B, fq);
fq_mul_ui(tmp_fq, tmp_fq, 27, fq);
fq_pow_ui(delta, A, 3, fq);
fq_mul_ui(delta, delta, 4, fq);
fq_add(delta, delta, tmp_fq, fq);
fq_mul_ui(delta, delta, 16, fq);
fq_neg(delta, delta, fq);
if(fq_is_zero(delta, fq))
{
fprintf(stderr, "The input parameters don't give us a elliptic curve.\n"); exit(EXIT_FAILURE);
}
// Libération mémoire
fq_clear(delta, fq); fq_clear(tmp_fq, fq);
// Fonction schoof
printf("La fonction de schoof :\n");
schoof(card, A, B, q, fq);
// Affichage du résultat
printf("Le cardinal est "); fmpz_print(card); printf("\n");
// Libération mémoire
fq_clear(A, fq); fq_clear(B, fq);
fq_ctx_clear(fq);
fmpz_clear(q); fmpz_clear(card);
exit(EXIT_SUCCESS);
}