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/*
Copyright (C) 2011, 2012 Sebastian Pancratz
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "long_extras.h"
#include "fmpq.h"
#include "padic.h"
char * _padic_get_str(char *str, const padic_t op, const fmpz_t p, enum padic_print_mode mode)
{
const fmpz *u = padic_unit(op);
const slong v = padic_val(op);
if (fmpz_is_zero(u))
{
if (!str)
{
str = flint_malloc(2);
}
str[0] = '0';
str[1] = '\0';
return str;
}
if (mode == PADIC_TERSE)
{
if (v == 0)
{
str = fmpz_get_str(str, 10, u);
}
else if (v > 0)
{
fmpz_t t;
fmpz_init(t);
fmpz_pow_ui(t, p, v);
fmpz_mul(t, t, u);
str = fmpz_get_str(str, 10, t);
fmpz_clear(t);
}
else /* v < 0 */
{
fmpz_t t;
fmpz_init(t);
fmpz_pow_ui(t, p, -v);
str = _fmpq_get_str(str, 10, u, t);
fmpz_clear(t);
}
}
else if (mode == PADIC_SERIES)
{
char *s;
fmpz_t x;
fmpz_t d;
slong j, N;
N = fmpz_clog(u, p) + v + 1;
if (!str)
{
slong b = (N - v) * (2 * fmpz_sizeinbase(p, 10)
+ z_sizeinbase(FLINT_MAX(FLINT_ABS(v), FLINT_ABS(N)), 10)
+ 5) + 1;
str = flint_malloc(b);
if (!str)
{
flint_throw(FLINT_ERROR, "Exception (padic_get_str). Memory allocation failed.\n");
}
}
s = str;
fmpz_init(d);
fmpz_init(x);
fmpz_set(x, u);
/* Unroll first step */
j = 0;
{
fmpz_mod(d, x, p); /* d = u mod p^{j+1} */
fmpz_sub(x, x, d); /* x = x - d */
fmpz_divexact(x, x, p); /* x = x / p */
if (!fmpz_is_zero(d))
{
if (j + v != 0)
{
fmpz_get_str(s, 10, d);
while (*++s != '\0') ;
*s++ = '*';
fmpz_get_str(s, 10, p);
while (*++s != '\0') ;
*s++ = '^';
flint_sprintf(s, "%wd", j + v);
while (*++s != '\0') ;
}
else
{
fmpz_get_str(s, 10, d);
while (*++s != '\0') ;
}
}
j++;
}
for ( ; !fmpz_is_zero(x); j++)
{
fmpz_mod(d, x, p); /* d = u mod p^{j+1} */
fmpz_sub(x, x, d); /* x = x - d */
fmpz_divexact(x, x, p); /* x = x / p */
if (!fmpz_is_zero(d))
{
if (j + v != 0)
{
*s++ = ' ';
*s++ = '+';
*s++ = ' ';
fmpz_get_str(s, 10, d);
while (*++s != '\0') ;
*s++ = '*';
fmpz_get_str(s, 10, p);
while (*++s != '\0') ;
*s++ = '^';
flint_sprintf(s, "%wd", j + v);
while (*++s != '\0') ;
}
else
{
*s++ = ' ';
*s++ = '+';
*s++ = ' ';
fmpz_get_str(s, 10, d);
while (*++s != '\0') ;
}
}
}
fmpz_clear(x);
fmpz_clear(d);
}
else /* ctx->mode == PADIC_VAL_UNIT */
{
if (!str)
{
slong b = fmpz_sizeinbase(u, 10) + fmpz_sizeinbase(p, 10)
+ z_sizeinbase(v, 10) + 4;
str = flint_malloc(b);
if (!str)
{
flint_throw(FLINT_ERROR, "Exception (padic_get_str). Memory allocation failed.\n");
}
}
if (v == 0)
{
str = fmpz_get_str(str, 10, u);
}
else if (v == 1)
{
char *s = str;
fmpz_get_str(s, 10, u);
while (*++s != '\0') ;
*s++ = '*';
fmpz_get_str(s, 10, p);
}
else
{
char *s = str;
fmpz_get_str(s, 10, u);
while (*++s != '\0') ;
*s++ = '*';
fmpz_get_str(s, 10, p);
while (*++s != '\0') ;
*s++ = '^';
flint_sprintf(s, "%wd", v);
}
}
return str;
}
char * padic_get_str(char *str, const padic_t op, const padic_ctx_t ctx)
{
return _padic_get_str(str, op, ctx->p, ctx->mode);
}