void
checkprimes (unsigned long p1, unsigned long p2, unsigned long p3)
{
mpz_t b, f;
if (p1 - 1 != p2 - 1 + p3 - 1)
{
printf ("checkprimes(%lu, %lu, %lu) wrong\n", p1, p2, p3);
printf (" %lu - 1 != %lu - 1 + %lu - 1 \n", p1, p2, p3);
abort ();
}
mpz_init (b);
mpz_init (f);
checkWilson (b, p1); /* b = (p1-1)! */
checkWilson (f, p2); /* f = (p2-1)! */
mpz_divexact (b, b, f);
checkWilson (f, p3); /* f = (p3-1)! */
mpz_divexact (b, b, f); /* b = (p1-1)!/((p2-1)!(p3-1)!) */
mpz_bin_uiui (f, p1 - 1, p2 - 1);
if (mpz_cmp (f, b) != 0)
{
printf ("checkprimes(%lu, %lu, %lu) wrong\n", p1, p2, p3);
printf (" got "); mpz_out_str (stdout, 10, b); printf("\n");
printf (" want "); mpz_out_str (stdout, 10, f); printf("\n");
abort ();
}
mpz_clear (b);
mpz_clear (f);
}
/**
* Computes the product of the first w primes such that the product <= B
*/
void mpz_bounded_primorial(int* w, mpz_t primorial, mpz_t phi, const mpz_t B) {
mpz_t p;
mpz_t t;
if (mpz_cmp_ui(B, 1) <= 0) {
mpz_set_ui(primorial, 0);
mpz_set_ui(phi, 0);
*w = 0;
return;
}
mpz_init_set_ui(p, 1);
mpz_init(t);
mpz_set_ui(primorial, 1);
mpz_set_ui(phi, 1);
*w = 0;
do {
mpz_nextprime(p, p);
(*w) ++;
mpz_mul(primorial, primorial, p);
mpz_sub_ui(t, p, 1);
mpz_mul(phi, phi, t);
} while (mpz_cmp(primorial, B) <= 0);
mpz_divexact(primorial, primorial, p);
mpz_divexact(phi, phi, t);
(*w) --;
mpz_clear(p);
mpz_clear(t);
}
void Qdet(mpq_t D, Qmat Min)
{
Qmat M;
int n, i, j, k;
mpz_t tmp, Dnum, Dden;
n = Min->nrows;
if (n == 1) { mpq_set(det, Min->entry[0][0]); return; }
M = Qmat(n, n);
for (i=0; i < n; i++)
for (j=0; j < n; j++)
mpq_set(M->entry[i][j], Min->entry[i][j]);
compute_row_lcm(row_lcm, M);
compute_col_lcm(col_lcm, M);
mpz_init(tmp);
mpz_init(Dnum);
mpz_init_set_ui(Dden, 1);
while ((k = choose_row_or_col(M, row_lcm, col_lcm)))
{
if (k > 0) /* the choice was row k-1 */
{
i = k-1;
mpz_mul(Dden, Dden, row_lcm[i]);
for (j=0; j < n; j++)
{
mpz_divexact(tmp, row_lcm[i], mpq_denref(M->entry[i][j]));
mpz_mul(mpq_numref(M->entry[i][j]), mpq_numref(M->entry[i][j]), tmp);
}
compute_col_lcm(col_lcm, M);
}
else /* the choice was col -k-1 */
{
j = -k-1;
mpz_mul(Dden, Dden, col_lcm[j]);
for (i=0; i < n; i++)
{
mpz_divexact(tmp, col_lcm[j], mpq_denref(M->entry[i][j]));
mpz_mul(mpq_numref(M->entry[i][j]), mpq_numref(M->entry[i][j]), tmp);
}
compute_row_lcm(row_lcm, M);
}
}
mpz_clear(tmp);
{
Zmat M_integer;
M_integer = Zmat_ctor(n, n);
for (i=0; i < n; i++)
for (j=0; j < n; j++)
mpz_set(M_integer[i][j], mpq_numref(M->entry[i][j]));
Zdet(Dnum, M_integer);
Zmat_dtor(M_integer);
mpz_set(mpq_numref(D), Dnum);
mpz_set(mpq_denref(D), Dden);
mpq_canonicalize(D);
}
Qmat_dtor(M);
}
static PyObject *
GMPy_MPZ_Function_Divexact(PyObject *self, PyObject *args)
{
PyObject *x, *y;
MPZ_Object *result, *tempx= NULL, *tempy = NULL;
if(PyTuple_GET_SIZE(args) != 2) {
TYPE_ERROR("divexact() requires 'mpz','mpz' arguments");
return NULL;
}
if (!(result = GMPy_MPZ_New(NULL))) {
/* LCOV_EXCL_START */
return NULL;
/* LCOV_EXCL_STOP */
}
x = PyTuple_GET_ITEM(args, 0);
y = PyTuple_GET_ITEM(args, 1);
if (MPZ_Check(x) && MPZ_Check(y)) {
if (mpz_sgn(MPZ(y)) == 0) {
ZERO_ERROR("divexact() division by 0");
Py_DECREF((PyObject*)result);
return NULL;
}
mpz_divexact(result->z, MPZ(x), MPZ(y));
}
else {
if (!(tempx = GMPy_MPZ_From_Integer(x, NULL)) ||
!(tempy = GMPy_MPZ_From_Integer(y, NULL))) {
TYPE_ERROR("divexact() requires 'mpz','mpz' arguments");
Py_XDECREF((PyObject*)tempx);
Py_XDECREF((PyObject*)tempy);
Py_DECREF((PyObject*)result);
return NULL;
}
if (mpz_sgn(MPZ(tempy)) == 0) {
ZERO_ERROR("divexact() division by 0");
Py_DECREF((PyObject*)tempx);
Py_DECREF((PyObject*)tempy);
Py_DECREF((PyObject*)result);
return NULL;
}
mpz_divexact(result->z, tempx->z, tempy->z);
Py_DECREF((PyObject*)tempx);
Py_DECREF((PyObject*)tempy);
}
return (PyObject*)result;
}
/*
* Store a value in a PP structure.
* Input:
* pp_pp* pp: pointer to the PP structure to store in
* mpq_t value: the value to store
* int parent: the parent to refer to
* int self: TRUE if value represents 1/parent, FALSE if it represents the
* resolution of pp[parent]
* Returns:
* Nothing.
* Effect:
* The specified value is stored in the specified PP structure, with a
* reference to the specified parent. Internal variables are updated
* accordingly.
*
* For a given value q, the caller is expected to have determined the
* greatest prime power p^k dividing the denominator of q. In this case,
* the pp structure should be that for p^k.
*
* The parent is used solely for determining a final solution vector.
* If the value is a source value (i.e. 1/r representing the integer
* r in the solution vector), the parent should be set to r, and self should
* be TRUE. If not, the parent is assumed to be a fully resolved PP structure
* storing a walk result that specifies the actual vector contribution
* (possibly recursively), and self should be FALSE.
*/
void pp_save_any(pp_pp* pp, mpq_t value, int parent, int self) {
int i;
mpz_t zvalue;
pp_value* v;
ZINIT(&zvalue, "pp_save_any zvalue");
/* new value = mpq_numref(value) * (denominator / mpq_denref(value))
* new_pp() setting of denominator guarantees exactness
*/
mpz_divexact(zvalue, pp->denominator, mpq_denref(value));
mpz_mul(zvalue, zvalue, mpq_numref(value));
/* adding to total may change required fixed size, at worst once per pp */
mpz_add(pp->total, pp->total, zvalue);
if (pp->total->_mp_size > pp->valnumsize) {
Dprintf("pp_%d: growing to %d with total %Zd (denom %Zd)\n",
pp->pp, pp->total->_mp_size, pp->total, pp->denominator);
pp_grownum(pp, pp->total->_mp_size);
}
++pp->valsize;
pp_grow(pp, pp->valsize);
v = pp_value_i(pp, pp->valsize - 1);
v->parent = parent;
v->self = self;
v->inv = (pp->invdenom * mod_ui(zvalue, pp->p)) % pp->p; /* ref: MAX_P */
mpx_set_z(ppv_mpx(v), pp->valnumsize, zvalue);
pp->invtotal = (pp->invtotal + v->inv) % pp->p;
pp_insert_last(pp);
ZCLEAR(&zvalue, "pp_save_any zvalue");
}
static Variant HHVM_FUNCTION(gmp_divexact,
const Variant& dataA,
const Variant& dataB) {
mpz_t gmpDataA, gmpDataB, gmpReturn;
if (!variantToGMPData(cs_GMP_FUNC_NAME_GMP_DIVEXACT, gmpDataA, dataA)) {
return false;
}
if (!variantToGMPData(cs_GMP_FUNC_NAME_GMP_DIVEXACT, gmpDataB, dataB)) {
mpz_clear(gmpDataA);
return false;
}
if (mpz_sgn(gmpDataB) == 0) {
raise_warning(cs_GMP_INVALID_VALUE_MUST_NOT_BE_ZERO,
cs_GMP_FUNC_NAME_GMP_DIVEXACT);
mpz_clear(gmpDataA);
mpz_clear(gmpDataB);
return false;
}
mpz_init(gmpReturn);
mpz_divexact(gmpReturn, gmpDataA, gmpDataB);
Variant ret = NEWOBJ(GMPResource)(gmpReturn);
mpz_clear(gmpDataA);
mpz_clear(gmpDataB);
mpz_clear(gmpReturn);
return ret;
}
unsigned long int nCr(unsigned long int n, unsigned long int r) {
mpz_t a,b,c, answer;
unsigned long int ret;
mpz_init(answer);
mpz_init(a);
mpz_init(b);
mpz_init(c);
if(n>r) {
mpz_fac_ui(a,n);
mpz_fac_ui(b,r);
mpz_fac_ui(c,n-r);
mpz_mul(b,b,c);
mpz_divexact(answer,a,b);
} else {
mpz_set_ui(answer,0);
}
ret = mpz_get_ui(answer);
mpz_clear(answer);
mpz_clear(a);
mpz_clear(b);
mpz_clear(c);
return ret;
}
void UniZRootZ_ByFactor(std::vector<mpz_ptr> & rootlist,const poly_z & f)
{
static mpz_t b,a;
std::vector<poly_z> faclist;
std::vector<uint> deglist;
mpz_init(b);
mpz_init(a);
UniFacZ(f,b,faclist,deglist);
uint totalroots=0;
for(uint i=0; i<faclist.size(); i++)
{
if(faclist[i].size()==2)
{
mpz_set(a,faclist[i][1]);
mpz_neg(b,faclist[i][0]);
if(mpz_divisible_p(b,a)!=0)
{
totalroots++;
resize_z_list(rootlist,totalroots);
mpz_divexact(rootlist[totalroots-1],b,a);
}
}
}
mpz_clear(b);
mpz_clear(a);
clear_poly_z_list(faclist);
std::sort(rootlist.begin(),rootlist.end(),mpz_ptr_less);
return ;
}
int factor(mpz_t x_1, mpz_t x_2, mpz_t d, mpz_t n, mpz_t tmp, mpz_t *factors)
{
int num_factors = 0;
while (IS_ONE(n) != 0 && IS_PRIME(n) == 0) {
/*pollard(x_1, x_2, d, n, 2, 1, MAX_NUMBER_OF_TRIES);*/
pollard_brent(x_1, x_2, d, n, 2, 3, MAX_NUMBER_OF_TRIES);
if(FAILED(d)) {
return 0;
}
while (IS_ONE(d) != 0 && IS_PRIME(d) == 0) {
/*pollard(x_2, x_2, tmp, d, 2, 1, MAX_NUMBER_OF_TRIES);*/
pollard_brent(x_1, x_2, d, n, 2, 3, MAX_NUMBER_OF_TRIES);
if(FAILED(tmp)) {
return 0;
}
mpz_set(d, tmp);
}
do {
ADD_FACTOR(factors, num_factors, d);
mpz_divexact(n, n, d);
} while (mpz_divisible_p(n, d));
}
if(IS_ONE(n) != 0) {
ADD_FACTOR(factors, num_factors, n);
}
return num_factors;
}
/* See Cohen 1.5.3 */
int modified_cornacchia(mpz_t x, mpz_t y, mpz_t D, mpz_t p)
{
int result = 0;
mpz_t a, b, c, d;
if (mpz_cmp_ui(p, 2) == 0) {
mpz_add_ui(x, D, 8);
if (mpz_perfect_square_p(x)) {
mpz_sqrt(x, x);
mpz_set_ui(y, 1);
result = 1;
}
return result;
}
if (mpz_jacobi(D, p) == -1) /* No solution */
return 0;
mpz_init(a);
mpz_init(b);
mpz_init(c);
mpz_init(d);
sqrtmod(x, D, p, a, b, c, d);
if ( (mpz_even_p(D) && mpz_odd_p(x)) || (mpz_odd_p(D) && mpz_even_p(x)) )
mpz_sub(x, p, x);
mpz_mul_ui(a, p, 2);
mpz_set(b, x);
mpz_sqrt(c, p);
mpz_mul_ui(c, c, 2);
/* Euclidean algorithm */
while (mpz_cmp(b, c) > 0) {
mpz_set(d, a);
mpz_set(a, b);
mpz_mod(b, d, b);
}
mpz_mul_ui(c, p, 4);
mpz_mul(a, b, b);
mpz_sub(a, c, a); /* a = 4p - b^2 */
mpz_abs(d, D); /* d = |D| */
if (mpz_divisible_p(a, d)) {
mpz_divexact(c, a, d);
if (mpz_perfect_square_p(c)) {
mpz_set(x, b);
mpz_sqrt(y, c);
result = 1;
}
}
mpz_clear(a);
mpz_clear(b);
mpz_clear(c);
mpz_clear(d);
return result;
}
void Integer::gcd(const Integer& a, const Integer& b) {
assert(this != &a);
assert(this != &b);
assert(a.divisible(b));
#ifdef GINV_INTEGER_ALLOCATOR
reallocate(abs(a.mMpz._mp_size) - abs(b.mMpz._mp_size) + 1);
#endif // GINV_INTEGER_ALLOCATOR
mpz_divexact(&mMpz, &a.mMpz, &b.mMpz);
}
void
mpz_lcm (mpz_ptr r, mpz_srcptr u, mpz_srcptr v)
{
mpz_t g;
mp_size_t usize, vsize;
TMP_DECL;
usize = SIZ (u);
vsize = SIZ (v);
if (usize == 0 || vsize == 0)
{
SIZ (r) = 0;
return;
}
usize = ABS (usize);
vsize = ABS (vsize);
if (vsize == 1 || usize == 1)
{
mp_limb_t vl, gl, c;
mp_srcptr up;
mp_ptr rp;
if (usize == 1)
{
usize = vsize;
MPZ_SRCPTR_SWAP (u, v);
}
MPZ_REALLOC (r, usize+1);
up = PTR(u);
vl = PTR(v)[0];
gl = mpn_gcd_1 (up, usize, vl);
vl /= gl;
rp = PTR(r);
c = mpn_mul_1 (rp, up, usize, vl);
rp[usize] = c;
usize += (c != 0);
SIZ(r) = usize;
return;
}
TMP_MARK;
MPZ_TMP_INIT (g, usize); /* v != 0 implies |gcd(u,v)| <= |u| */
mpz_gcd (g, u, v);
mpz_divexact (g, u, g);
mpz_mul (r, g, v);
SIZ (r) = ABS (SIZ (r)); /* result always positive */
TMP_FREE;
}
/** \brief 整系数多项式本原部分.
\param f 整系数多项式.
\param r 本原部分.
\return 本原部分,其lc为正整数.
*/
void UniPPZ(poly_z & r,const poly_z & f)
{
mpz_t a;
mpz_init(a);
UniContZ(a,f);
r.resize(f.size());
for(size_t i=0;i<f.size();i++)
{
mpz_divexact(r[i],f[i],a);
}
mpz_clear(a);
}
///@brief test doc
bool divide(ElementType& result,
const ElementType& a,
const ElementType& b) const
{
if (mpz_divisible_p(&a, &b))
{
mpz_divexact(&result, &a, &b);
return true;
}
else
return false;
}
static int insert_factor(mpz_t n, mpz_t* farray, int nfacs, mpz_t f)
{
int i, j;
mpz_t t, t2;
if (mpz_cmp_ui(f, 1) <= 0)
return nfacs;
/* skip duplicates */
for (i = 0; i < nfacs; i++)
if (mpz_cmp(farray[i], f) == 0)
break;
if (i != nfacs) { return nfacs; }
/* Look for common factors in all the existing set */
/* for (i = 0; i < nfacs; i++) gmp_printf(" F[%d] = %Zd\n", i, farray[i]); */
mpz_init(t); mpz_init(t2);
for (i = 0; i < nfacs; i++) {
mpz_gcd(t, farray[i], f);
if (mpz_cmp_ui(t, 1) == 0) /* t=1: F and f unchanged */
continue;
mpz_divexact(t2, farray[i], t); /* t2 = F/t */
mpz_divexact(f, f, t); /* f = f/t */
/* Remove the old farray[i] */
for (j = i+1; j < nfacs; j++)
mpz_set(farray[j-1], farray[j]);
mpz_set_ui(farray[nfacs--], 0);
/* Insert F/t, t, f/t */
nfacs = insert_factor(n, farray, nfacs, t2);
nfacs = insert_factor(n, farray, nfacs, t);
nfacs = insert_factor(n, farray, nfacs, f);
i=0;
break;
}
/* If nothing common, insert it. */
if (i == nfacs)
mpz_set(farray[nfacs++], f);
mpz_clear(t); mpz_clear(t2);
return nfacs;
}
// Liefert die Primfaktorzerlegung einer Zahl als String.
char *factorize(mpz_t number)
{
// Primtest (Miller-Rabin).
if (mpz_probab_prime_p(number, 10) > 0)
return mpz_get_str(NULL, 10, number);
mpz_t factor, cofactor;
mpz_init(factor);
mpz_init(cofactor);
char *str1, *str2, *result;
int B1 = INITB1, B2 = INITB2, curves = INITCURVES;
// Zunaechst eine einfache Probedivision.
trial(number, factor, 3e3);
if (mpz_cmp_si(factor, 1) == 0)
{
// Zweite Strategie: Pollard-Rho.
do
{
rho(number, factor, 4e4);
} while (mpz_cmp(factor, number) == 0);
// Falls immer noch kein Faktor gefunden wurde, mit ECM fortfahren.
while (mpz_cmp_si(factor, 1) == 0)
{
ecm(number, factor, B1, B2, curves);
if (mpz_cmp(factor, number) == 0)
{
mpz_set_si(factor, 1);
B1 = INITB1;
B2 = INITB2;
curves = INITCURVES;
continue;
}
// Anpassung der Parameter.
B1 *= 4;
B2 *= 5;
curves = (curves * 5) / 2;
}
}
mpz_divexact(cofactor, number, factor);
str1 = factorize(factor);
str2 = factorize(cofactor);
result = (char *) malloc(strlen(str1) + strlen(str2) + 4);
strcpy(result, str1);
strcat(result, " * ");
strcat(result, str2);
mpz_clear(factor);
mpz_clear(cofactor);
return result;
}
void init_ecpp_gcds(void) {
if (_gcdinit == 0) {
mpz_init(_gcd_small);
mpz_init(_gcd_large);
_GMP_pn_primorial(_gcd_small, 3000);
_GMP_pn_primorial(_gcd_large, 20000);
mpz_divexact(_gcd_large, _gcd_large, _gcd_small);
mpz_divexact_ui(_gcd_small, _gcd_small, 2*3*5);
mpz_init(_lcm_small);
_GMP_lcm_of_consecutive_integers(300, _lcm_small);
_gcdinit = 1;
}
}
static void initpq(params_t params)
//calculate system parameters that can be determined from p and q
//also initialize the elliptic curve library so points can be used
{
mpz_init(params->p1onq);
mpz_add_ui(params->p1onq, params->p, 1);
mpz_divexact(params->p1onq, params->p1onq, params->q);
//initialize the elliptic curve library
curve_init(params->curve, params->p, params->q);
fp2_init(params->zeta);
fp2_set_cbrt_unity(params->zeta, params->p);
}
unsigned long my_div_estimate_threshold()
{
const double log10 = 3.321928;
clock_t begin, end, diff1, diff2;
mpz_t y, x;
unsigned long digits = 100, min_digits, max_digits, prec, stage = 1;
div_threshold = 0;
for (;;) {
if (stage == 1)
digits *= 2;
else
digits = (min_digits + max_digits)/2;
prec = (unsigned long) (digits * log10) + 32;
my_init(prec);
mpz_init(y);
mpz_init(x);
mpz_ui_pow_ui(y, 10, digits);
mpz_ui_pow_ui(x, 10, digits/10);
begin = clock();
my_divexact(y, y, x);
end = clock();
diff1 = end - begin;
mpz_ui_pow_ui(y, 10, digits);
begin = clock();
mpz_divexact(y, y, x);
end = clock();
diff2 = end - begin;
my_clear();
mpz_clear(y);
mpz_clear(x);
printf("digits %ld, my %ld, mpz %ld\n", digits, diff1, diff2);
if (stage == 1) {
if (diff1 >= 10 && diff1 < diff2) {
stage = 2;
min_digits = digits/2;
max_digits = digits;
}
} else {
if (diff1 < diff2)
max_digits = digits;
else
min_digits = digits;
if (max_digits - min_digits < 100)
break;
}
}
return (unsigned long) (digits * log10);
}
/* f /= gcd(f,g), g /= gcd(f,g) */
void
fac_remove_gcd(mpz_t p, fac_t fp, mpz_t g, fac_t fg)
{
long int i, j, k, c;
fac_resize(fmul, min(fp->num_facs, fg->num_facs));
for (i=j=k=0; i<fp->num_facs && j<fg->num_facs; ) {
if (fp->fac[i] == fg->fac[j]) {
c = min(fp->pow[i], fg->pow[j]);
fp->pow[i] -= c;
fg->pow[j] -= c;
fmul->fac[k] = fp->fac[i];
fmul->pow[k] = c;
i++; j++; k++;
} else if (fp->fac[i] < fg->fac[j]) {
i++;
} else {
j++;
}
}
fmul->num_facs = k;
assert(k <= fmul->max_facs);
if (fmul->num_facs) {
bs_mul(gcd, 0, fmul->num_facs);
#if HAVE_DIVEXACT_PREINV
mpz_invert_mod_2exp (mgcd, gcd);
mpz_divexact_pre (p, p, gcd, mgcd);
mpz_divexact_pre (g, g, gcd, mgcd);
#else
#define SIZ(x) x->_mp_size
mpz_divexact(p, p, gcd);
mpz_divexact(g, g, gcd);
#endif
fac_compact(fp);
fac_compact(fg);
}
}
void init_ecpp_gcds(UV nsize) {
if (_gcdinit == 0) {
mpz_init(_gcd_small);
mpz_init(_gcd_large);
_GMP_pn_primorial(_gcd_small, 3000);
/* This is never re-adjusted -- first number proved sets the size */
nsize *= 20;
if (nsize < 20000) nsize = 20000;
else if (nsize > 500000) nsize = 500000;
_GMP_pn_primorial(_gcd_large, nsize);
mpz_divexact(_gcd_large, _gcd_large, _gcd_small);
mpz_divexact_ui(_gcd_small, _gcd_small, 2*3*5);
_gcdinit = 1;
}
}
int main(void)
{
mpz_t a, b;
mpz_init(a);
mpz_init(b);
/* 40C20 */
mpz_fac_ui(a, 40);
mpz_fac_ui(b, 20);
mpz_mul(b, b, b);
mpz_divexact(a, a, b);
gmp_printf("%Zd\n", a);
return 0;
}
void choose(mpz_t ans, int n, int r) {
factorial(ans, n);
mpz_t smaller;
factorial(smaller, r);
mpz_t third;
factorial(third, n-r);
/* gmp_printf("smaller is: %Zd\n", smaller); */
/* gmp_printf("third is: %Zd\n", third); */
mpz_mul(smaller, smaller, third);
/* gmp_printf("top is: %Zd\n", ans); */
/* gmp_printf("smaller is: %Zd\n", smaller); */
mpz_divexact(ans, ans, smaller);
}
void decrypt(mpz_t c){
//set big_temp = c^d mod n^2
mpz_powm(big_temp, c, d, n_square);
//set big_temp = big_temp -1
mpz_sub_ui(big_temp, big_temp, 1);
//divide big_temp by n
mpz_divexact(big_temp, big_temp, n);
//d^-1 * big_temp
mpz_mul(big_temp, d_inverse, big_temp);
mpz_mod(c, big_temp, n);
}
/*
* Algorithm as seen in the initial paper. Simple optimizations
* have been added. rop and op can be aliases.
*/
static void dlog_s(djcs_private_key *vk, mpz_t rop, mpz_t op)
{
mpz_t a, t1, t2, t3, kfact;
mpz_inits(a, t1, t2, t3, kfact, NULL);
/* Optimization: L(a mod n^(j+1)) = L(a mod n^(s+1)) mod n^j
* where j <= s */
mpz_mod(a, op, vk->n[vk->s]);
mpz_sub_ui(a, a, 1);
mpz_divexact(a, a, vk->n[0]);
mpz_set_ui(rop, 0);
for (unsigned long j = 1; j <= vk->s; ++j) {
/* t1 = L(a mod n^j+1) */
mpz_mod(t1, a, vk->n[j-1]);
/* t2 = i */
mpz_set(t2, rop);
mpz_set_ui(kfact, 1);
for (unsigned long k = 2; k <= j; ++k) {
/* i = i - 1 */
mpz_sub_ui(rop, rop, 1);
mpz_mul_ui(kfact, kfact, k);
/* t2 = t2 * i mod n^j */
mpz_mul(t2, t2, rop);
mpz_mod(t2, t2, vk->n[j-1]);
/* t1 = t1 - (t2 * n^(k-1)) * k!^(-1)) mod n^j */
mpz_invert(t3, kfact, vk->n[j-1]);
mpz_mul(t3, t3, t2);
mpz_mod(t3, t3, vk->n[j-1]);
mpz_mul(t3, t3, vk->n[k-2]);
mpz_mod(t3, t3, vk->n[j-1]);
mpz_sub(t1, t1, t3);
mpz_mod(t1, t1, vk->n[j-1]);
}
mpz_set(rop, t1);
}
mpz_zeros(a, t1, t2, t3, kfact, NULL);
mpz_clears(a, t1, t2, t3, kfact, NULL);
}
/* div */
static int divide(void *a, void *b, void *c, void *d)
{
mpz_t tmp;
LTC_ARGCHK(a != NULL);
LTC_ARGCHK(b != NULL);
if (c != NULL) {
mpz_init(tmp);
mpz_divexact(tmp, a, b);
}
if (d != NULL) {
mpz_mod(d, a, b);
}
if (c != NULL) {
mpz_set(c, tmp);
mpz_clear(tmp);
}
return CRYPT_OK;
}
/* See Cohen 1.5.2 */
int cornacchia(mpz_t x, mpz_t y, mpz_t D, mpz_t p)
{
int result = 0;
mpz_t a, b, c, d;
if (mpz_jacobi(D, p) < 0) /* No solution */
return 0;
mpz_init(a);
mpz_init(b);
mpz_init(c);
mpz_init(d);
sqrtmod(x, D, p, a, b, c, d);
mpz_set(a, p);
mpz_set(b, x);
mpz_sqrt(c, p);
while (mpz_cmp(b,c) > 0) {
mpz_set(d, a);
mpz_set(a, b);
mpz_mod(b, d, b);
}
mpz_mul(a, b, b);
mpz_sub(a, p, a); /* a = p - b^2 */
mpz_abs(d, D); /* d = |D| */
if (mpz_divisible_p(a, d)) {
mpz_divexact(c, a, d);
if (mpz_perfect_square_p(c)) {
mpz_set(x, b);
mpz_sqrt(y, c);
result = 1;
}
}
mpz_clear(a);
mpz_clear(b);
mpz_clear(c);
mpz_clear(d);
return result;
}
void
fmpz_divexact(fmpz_t f, const fmpz_t g, const fmpz_t h)
{
fmpz c1 = *g;
fmpz c2 = *h;
if (fmpz_is_zero(h))
{
flint_printf("Exception (fmpz_divexact). Division by zero.\n");
abort();
}
if (!COEFF_IS_MPZ(c1)) /* g is small, h must be also or division isn't exact */
{
fmpz_set_si(f, c1 / c2);
}
else /* g is large */
{
__mpz_struct * mpz_ptr = _fmpz_promote(f);
if (!COEFF_IS_MPZ(c2)) /* h is small */
{
if (c2 > 0) /* h > 0 */
{
flint_mpz_divexact_ui(mpz_ptr, COEFF_TO_PTR(c1), c2);
_fmpz_demote_val(f); /* division by h may result in small value */
}
else
{
flint_mpz_divexact_ui(mpz_ptr, COEFF_TO_PTR(c1), -c2);
_fmpz_demote_val(f); /* division by h may result in small value */
fmpz_neg(f, f);
}
}
else /* both are large */
{
mpz_divexact(mpz_ptr, COEFF_TO_PTR(c1), COEFF_TO_PTR(c2));
_fmpz_demote_val(f); /* division by h may result in small value */
}
}
}
void *SumThread(void *context)
{
PSUM_THREAD_CONTEXT tcontext = (PSUM_THREAD_CONTEXT)context;
while (mpz_cmp(tcontext->factor, tcontext->end) < 0)
{
//Check if the number is divisible by the factor
if (mpz_divisible_p(tcontext->num, tcontext->factor) != 0)
{
pthread_mutex_lock(tcontext->termMutex);
//Add the factor
mpz_add(*tcontext->sum, *tcontext->sum, tcontext->factor);
//Add the other factor in the pair
mpz_divexact(tcontext->otherfactor, tcontext->num, tcontext->factor);
mpz_add(*tcontext->sum, *tcontext->sum, tcontext->otherfactor);
//Bail early if we've exceeded our number
if (mpz_cmp(*tcontext->sum, tcontext->num) > 0)
{
pthread_mutex_unlock(tcontext->termMutex);
break;
}
pthread_mutex_unlock(tcontext->termMutex);
}
//This is a valid cancellation point
pthread_testcancel();
mpz_add_ui(tcontext->factor, tcontext->factor, 1);
}
pthread_mutex_lock(tcontext->termMutex);
(*tcontext->termCount)++;
pthread_cond_signal(tcontext->termVar);
pthread_mutex_unlock(tcontext->termMutex);
pthread_exit(NULL);
}
/* Return non-zero iff c+i*d is an exact square (a+i*b)^2,
with a, b both of the form m*2^e with m, e integers.
If so, returns in a+i*b the corresponding square root, with a >= 0.
The variables a, b must not overlap with c, d.
We have c = a^2 - b^2 and d = 2*a*b.
If one of a, b is exact, then both are (see algorithms.tex).
Case 1: a <> 0 and b <> 0.
Let a = m*2^e and b = n*2^f with m, e, n, f integers, m and n odd
(we will treat apart the case a = 0 or b = 0).
Then 2*a*b = m*n*2^(e+f+1), thus necessarily e+f >= -1.
Assume e < 0, then f >= 0, then a^2 - b^2 = m^2*2^(2e) - n^2*2^(2f) cannot
be an integer, since n^2*2^(2f) is an integer, and m^2*2^(2e) is not.
Similarly when f < 0 (and thus e >= 0).
Thus we have e, f >= 0, and a, b are both integers.
Let A = 2a^2, then eliminating b between c = a^2 - b^2 and d = 2*a*b
gives A^2 - 2c*A - d^2 = 0, which has solutions c +/- sqrt(c^2+d^2).
We thus need c^2+d^2 to be a square, and c + sqrt(c^2+d^2) --- the solution
we are interested in --- to be two times a square. Then b = d/(2a) is
necessarily an integer.
Case 2: a = 0. Then d is necessarily zero, thus it suffices to check
whether c = -b^2, i.e., if -c is a square.
Case 3: b = 0. Then d is necessarily zero, thus it suffices to check
whether c = a^2, i.e., if c is a square.
*/
static int
mpc_perfect_square_p (mpz_t a, mpz_t b, mpz_t c, mpz_t d)
{
if (mpz_cmp_ui (d, 0) == 0) /* case a = 0 or b = 0 */
{
/* necessarily c < 0 here, since we have already considered the case
where x is real non-negative and y is real */
MPC_ASSERT (mpz_cmp_ui (c, 0) < 0);
mpz_neg (b, c);
if (mpz_perfect_square_p (b)) /* case 2 above */
{
mpz_sqrt (b, b);
mpz_set_ui (a, 0);
return 1; /* c + i*d = (0 + i*b)^2 */
}
}
else /* both a and b are non-zero */
{
if (mpz_divisible_2exp_p (d, 1) == 0)
return 0; /* d must be even */
mpz_mul (a, c, c);
mpz_addmul (a, d, d); /* c^2 + d^2 */
if (mpz_perfect_square_p (a))
{
mpz_sqrt (a, a);
mpz_add (a, c, a); /* c + sqrt(c^2+d^2) */
if (mpz_divisible_2exp_p (a, 1))
{
mpz_tdiv_q_2exp (a, a, 1);
if (mpz_perfect_square_p (a))
{
mpz_sqrt (a, a);
mpz_tdiv_q_2exp (b, d, 1); /* d/2 */
mpz_divexact (b, b, a); /* d/(2a) */
return 1;
}
}
}
}
return 0; /* not a square */
}
