/* p-adic logarithm */
void padiclog(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo) {
/* Compute the p-adic logarithm of a,
which is supposed to be congruent to 1 mod p
Algorithm:
1. we raise a at the power p^(v-1) (for a suitable v) in order
to make it closer to 1
2. we write the new a as a product
1/a = (1 - a_0*p^v) (1 - a_1*p^(2*v) (1 - a_2*p^(4*v) ...
with 0 <= a_i < p^(v*2^i).
3. we compute each log(1 - a_i*p^(v*2^i)) using Taylor expansion
and a binary spliting strategy. */
unsigned long i, v, e, N, saveN, Np, tmp, trunc, step;
double den = log(p);
mpz_t f, arg, trunc_mod, h, hpow, mpz_tmp, mpz_tmp2, d, inv, mod2;
mpz_t *num, *denom;
mpz_init(mpz_tmp);
mpz_init(mpz_tmp2);
mpz_init(arg);
mpz_set_ui(ans, 0);
mpz_fdiv_r_ui(mpz_tmp, a, p);
mpz_set(arg, a);
/* First we make the argument closer to 1 by raising it to the p^(v-1) */
if (prec < p) {
v = 0; e = 1;
} else {
v = (unsigned long)(log(prec)/den); // v here is v-1
e = pow(p,v);
mpz_mul_ui(mpz_tmp, modulo, e);
mpz_powm_ui(arg, arg, e, mpz_tmp);
prec += v;
}
/* Where do we need to truncate the Taylor expansion */
N = prec+v; N /= ++v; // note the ++v
Np = N;
den *= v;
while(1) {
tmp = Np + (unsigned long)(log(N)/den);
if (tmp == N) break;
N = tmp;
}
/* We allocate memory and initialize variables */
mpz_init(f); mpz_init(mod2);
mpz_init(h); mpz_init(hpow);
mpz_init(d); mpz_init(inv);
sig_block();
num = (mpz_t*)malloc(N*sizeof(mpz_t));
denom = (mpz_t*)malloc(N*sizeof(mpz_t));
sig_unblock();
for (i = 0; i < N; i++) {
mpz_init(num[i]);
mpz_init(denom[i]);
}
trunc = v << 1;
mpz_init(trunc_mod);
mpz_ui_pow_ui(trunc_mod, p, trunc);
while(1) {
/* We compute f = 1 - a_i*p^((v+1)*2^i)
trunc_mod is p^((v+1)*2^(i+1)) */
mpz_fdiv_r(f, arg, trunc_mod);
if (mpz_cmp_ui(f, 1) != 0) {
mpz_ui_sub(f, 2, f);
mpz_mul(arg, arg, f);
/* We compute the Taylor expansion of log(f)
For now, computations are carried out over the rationals */
for (i = 0; i < N; i++) {
mpz_set_ui(num[i], 1);
mpz_set_ui(denom[i], i+1);
}
step = 1;
mpz_ui_sub(h, 1, f); // we write f = 1 - h, i.e. h = a_i*p^(2^i)
mpz_set(hpow, h);
while(step < N) {
for (i = 0; i < N - step; i += step << 1) {
mpz_mul(mpz_tmp2, hpow, num[i+step]);
mpz_mul(mpz_tmp, mpz_tmp2, denom[i]);
mpz_mul(num[i], num[i], denom[i+step]);
mpz_add(num[i], num[i], mpz_tmp);
mpz_mul(denom[i], denom[i], denom[i+step]);
}
step <<= 1;
mpz_mul(hpow, hpow, hpow);
}
/* We simplify the fraction */
Np = N; tmp = 0;
while(Np > 0) { Np /= p; tmp += Np; }
mpz_ui_pow_ui(d, p, tmp);
mpz_divexact(mpz_tmp, num[0], d);
mpz_divexact(denom[0], denom[0], d);
mpz_divexact_ui(h, h, e);
mpz_mul(mpz_tmp, h, mpz_tmp);
/* We coerce the result from Q to Zp */
mpz_gcdext(d, inv, NULL, denom[0], modulo);
mpz_mul(mpz_tmp, mpz_tmp, inv);
/* We add this contribution to log(f) */
mpz_add(ans, ans, mpz_tmp);
}
if (trunc > prec) break;
/* We update the variables for the next step */
mpz_mul(trunc_mod, trunc_mod, trunc_mod);
trunc <<= 1;
for (i = N >> 1; i < N; i++) {
mpz_clear(num[i]);
mpz_clear(denom[i]);
}
N >>= 1;
}
mpz_fdiv_r(ans, ans, modulo);
/* We clear memory */
mpz_clear(arg);
mpz_clear(f);
mpz_clear(trunc_mod);
mpz_clear(h);
mpz_clear(hpow);
mpz_clear(mpz_tmp);
mpz_clear(d);
mpz_clear(inv);
mpz_clear(mod2);
for (i = 0; i < N; i++) {
mpz_clear(num[i]);
mpz_clear(denom[i]);
}
sig_block();
free(num);
free(denom);
sig_unblock();
}
void
try_op_si (int c)
{
long si, oi;
mpz_t sz, oz;
si = c;
mpz_init_set_si (sz, si);
oi = si;
mpz_init_set (oz, sz);
do {
si *= 2; /* c * 2^k */
mpz_mul_2exp (sz, sz, 1);
if (check_si (sz, oz, si, oi, c))
{
mpz_set (oz, sz);
break;
}
oi = si + c; /* c * (2^k + 1) */
if (c == -1)
mpz_sub_ui (oz, sz, 1);
else
mpz_add_ui (oz, sz, 1);
if (check_si (oz, sz, oi, si, c))
break;
oi = (si - c) * 2 + c; /* c * (2^K - 1) */
mpz_mul_si (oz, sz, 2*c);
if (c == -1)
mpz_ui_sub (oz, 1, oz); /* oz = sz * 2 + 1 */
else
mpz_sub_ui (oz, oz, 1); /* oz = sz * 2 - 1 */
} while (check_si (oz, sz, oi, si, c) == 0);
mpz_clear (sz);
if (mpz_fits_slong_p (oz))
{
printf ("Should not fit a signed long any more.\n");
printf (" oz="); mpz_out_str (stdout, 10, oz); printf ("\n");
abort ();
}
if (mpz_cmp_si (oz, -c) != c)
{
printf ("mpz_cmp_si (oz, %i) != %i.\n", c, c);
printf (" oz="); mpz_out_str (stdout, 10, oz); printf ("\n");
abort ();
}
mpz_mul_2exp (oz, oz, 1);
if (mpz_cmp_si (oz, -c) != c)
{
printf ("mpz_cmp_si (oz, %i) != %i.\n", c, c);
printf (" oz="); mpz_out_str (stdout, 10, oz); printf ("\n");
abort ();
}
mpz_clear (oz);
}
int
main (int argc, char **argv)
{
mpz_t op1, op2, r1, r2;
mp_size_t op1n, op2n;
unsigned long int op2long;
int i;
int reps = 100000;
gmp_randstate_ptr rands;
mpz_t bs;
unsigned long bsi, size_range;
tests_start ();
rands = RANDS;
mpz_init (bs);
if (argc == 2)
reps = atoi (argv[1]);
mpz_init (op1);
mpz_init (op2);
mpz_init (r1);
mpz_init (r2);
for (i = 0; i < reps; i++)
{
mpz_urandomb (bs, rands, 32);
size_range = mpz_get_ui (bs) % 10 + 2;
mpz_urandomb (bs, rands, size_range);
op1n = mpz_get_ui (bs);
mpz_rrandomb (op1, rands, op1n);
mpz_urandomb (bs, rands, size_range);
op2n = mpz_get_ui (bs);
mpz_rrandomb (op2, rands, op2n);
mpz_urandomb (bs, rands, 2);
bsi = mpz_get_ui (bs);
if ((bsi & 1) != 0)
mpz_neg (op1, op1);
if ((bsi & 2) != 0)
mpz_neg (op2, op2);
/* printf ("%ld %ld\n", SIZ (multiplier), SIZ (multiplicand)); */
mpz_add (r1, op1, op2);
mpz_sub (r2, r1, op2);
if (mpz_cmp (r2, op1) != 0)
dump_abort (i, "mpz_add or mpz_sub incorrect", op1, op2);
if (mpz_fits_ulong_p (op2))
{
op2long = mpz_get_ui (op2);
mpz_add_ui (r1, op1, op2long);
mpz_sub_ui (r2, r1, op2long);
if (mpz_cmp (r2, op1) != 0)
dump_abort (i, "mpz_add_ui or mpz_sub_ui incorrect", op1, op2);
mpz_ui_sub (r1, op2long, op1);
mpz_sub_ui (r2, op1, op2long);
mpz_neg (r2, r2);
if (mpz_cmp (r1, r2) != 0)
dump_abort (i, "mpz_add_ui or mpz_ui_sub incorrect", op1, op2);
}
}
mpz_clear (bs);
mpz_clear (op1);
mpz_clear (op2);
mpz_clear (r1);
mpz_clear (r2);
tests_end ();
exit (0);
}
static PyObject *
GMPy_Integer_Sub(PyObject *x, PyObject *y, CTXT_Object *context)
{
MPZ_Object *result;
if (!(result = GMPy_MPZ_New(context)))
return NULL;
if (CHECK_MPZANY(x)) {
if (PyIntOrLong_Check(y)) {
int error;
long temp = GMPy_Integer_AsLongAndError(y, &error);
if (!error) {
if (temp >= 0) {
mpz_sub_ui(result->z, MPZ(x), temp);
}
else {
mpz_add_ui(result->z, MPZ(x), -temp);
}
}
else {
mpz_t tempz;
mpz_inoc(tempz);
mpz_set_PyIntOrLong(tempz, y);
mpz_sub(result->z, MPZ(x), tempz);
mpz_cloc(tempz);
}
return (PyObject*)result;
}
if (CHECK_MPZANY(y)) {
mpz_sub(result->z, MPZ(x), MPZ(y));
return (PyObject*)result;
}
}
if (CHECK_MPZANY(y)) {
if (PyIntOrLong_Check(x)) {
int error;
long temp = GMPy_Integer_AsLongAndError(x, &error);
if (!error) {
if (temp >= 0) {
mpz_ui_sub(result->z, temp, MPZ(y));
}
else {
mpz_add_ui(result->z, MPZ(y), -temp);
mpz_neg(result->z, result->z);
}
}
else {
mpz_t tempz;
mpz_inoc(tempz);
mpz_set_PyIntOrLong(tempz, x);
mpz_sub(result->z, tempz, MPZ(y));
mpz_cloc(tempz);
}
return (PyObject*)result;
}
}
if (IS_INTEGER(x) && IS_INTEGER(y)) {
MPZ_Object *tempx, *tempy;
tempx = GMPy_MPZ_From_Integer(x, context);
tempy = GMPy_MPZ_From_Integer(y, context);
if (!tempx || !tempy) {
Py_XDECREF((PyObject*)tempx);
Py_XDECREF((PyObject*)tempy);
Py_DECREF((PyObject*)result);
return NULL;
}
mpz_sub(result->z, tempx->z, tempy->z);
Py_DECREF((PyObject*)tempx);
Py_DECREF((PyObject*)tempy);
return (PyObject*)result;
}
Py_DECREF((PyObject*)result);
Py_RETURN_NOTIMPLEMENTED;
}
