pqc/external/flint-2.4.3/fmpq_poly/get_str_pretty.c

219 lines
6.2 KiB
C
Raw Normal View History

2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2010, 2011 Sebastian Pancratz
******************************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpq_poly.h"
char * _fmpq_poly_get_str_pretty(const fmpz *poly, const fmpz_t den, slong len,
const char *var)
{
slong i;
size_t j;
size_t size; /* Upper bound on the length */
size_t densize; /* Size of the denominator in base 10 */
size_t varsize; /* Length of the variable name */
mpz_t z; /* op->den (if this is not 1) */
mpq_t q;
char *str;
if (len == 0) /* Zero polynomial */
{
str = flint_malloc(2);
str[0] = '0';
str[1] = '\0';
return str;
}
if (len == 1) /* Constant polynomials */
{
mpq_init(q);
fmpz_get_mpz(mpq_numref(q), poly);
fmpz_get_mpz(mpq_denref(q), den);
mpq_canonicalize(q);
str = mpq_get_str(NULL, 10, q);
mpq_clear(q);
return str;
}
if (len == 2) /* Linear polynomials */
{
mpq_t a0, a1;
size_t size0, size1;
mpq_init(a0);
mpq_init(a1);
fmpz_get_mpz(mpq_numref(a0), poly);
fmpz_get_mpz(mpq_denref(a0), den);
mpq_canonicalize(a0);
fmpz_get_mpz(mpq_numref(a1), poly + 1);
fmpz_get_mpz(mpq_denref(a1), den);
mpq_canonicalize(a1);
size0 = mpz_sizeinbase(mpq_numref(a0), 10)
+ mpz_sizeinbase(mpq_denref(a0), 10) + 1;
size1 = mpz_sizeinbase(mpq_numref(a1), 10)
+ mpz_sizeinbase(mpq_denref(a1), 10) + 1;
size = size0 + 1 + strlen(var) + 1 + size1 + 1;
str = flint_malloc(size);
if (flint_mpq_cmp_si(a1, 1, 1) == 0)
{
if (mpq_sgn(a0) == 0)
gmp_sprintf(str, "%s", var);
else if (mpq_sgn(a0) > 0)
gmp_sprintf(str, "%s+%Qd", var, a0);
else /* mpq_sgn(a0) < 0 */
gmp_sprintf(str, "%s%Qd", var, a0);
}
else if (flint_mpq_cmp_si(a1, -1, 1) == 0)
{
if (mpq_sgn(a0) == 0)
gmp_sprintf(str, "-%s", var);
else if (mpq_sgn(a0) > 0)
gmp_sprintf(str, "-%s+%Qd", var, a0);
else /* mpq_sgn(a0) < 0 */
gmp_sprintf(str, "-%s%Qd", var, a0);
}
else
{
if (mpq_sgn(a0) == 0)
gmp_sprintf(str, "%Qd*%s", a1, var);
else if (mpq_sgn(a0) > 0)
gmp_sprintf(str, "%Qd*%s+%Qd", a1, var, a0);
else /* mpq_sgn(a0) < 0 */
gmp_sprintf(str, "%Qd*%s%Qd", a1, var, a0);
}
mpq_clear(a0);
mpq_clear(a1);
return str;
}
varsize = strlen(var);
/* Copy the denominator into an mpz_t */
mpz_init(z);
if (*den == WORD(1))
{
densize = 0;
}
else
{
fmpz_get_mpz(z, den);
densize = mpz_sizeinbase(z, 10);
}
/* Estimate the length */
size = 0;
for (i = 0; i < len; i++)
{
fmpz_get_mpz(z, poly + i);
size += mpz_sizeinbase(z, 10); /* Numerator */
if (mpz_sgn(z) != 0) size += 1 + densize; /* Denominator and / */
size += 3; /* Operator and ws */
size += 1 + varsize + 1; /* *, x and ^ */
size += (size_t) ceil(log10((double) (i + 1))); /* Exponent */
}
mpq_init(q);
str = flint_malloc(size);
j = 0;
/* Print the leading term */
fmpz_get_mpz(mpq_numref(q), poly + (len - 1));
fmpz_get_mpz(mpq_denref(q), den);
mpq_canonicalize(q);
if (flint_mpq_cmp_si(q, 1, 1) != 0)
{
if (flint_mpq_cmp_si(q, -1, 1) == 0)
str[j++] = '-';
else
{
mpq_get_str(str, 10, q);
j += strlen(str + j);
str[j++] = '*';
}
}
j += flint_sprintf(str + j, "%s", var);
str[j++] = '^';
j += flint_sprintf(str + j, "%li", len - 1);
i = len - 1;
while (i)
{
i--;
if (fmpz_is_zero(poly + i))
continue;
fmpz_get_mpz(mpq_numref(q), poly + i);
fmpz_get_mpz(mpq_denref(q), den);
mpq_canonicalize(q);
str[j++] = ' ';
if (mpq_sgn(q) < 0)
{
mpq_abs(q, q);
str[j++] = '-';
}
else
str[j++] = '+';
str[j++] = ' ';
mpq_get_str(str + j, 10, q);
j += strlen(str + j);
if (i > 0)
{
str[j++] = '*';
j += flint_sprintf(str + j, "%s", var);
if (i > 1)
{
str[j++] = '^';
j += flint_sprintf(str + j, "%li", i);
}
}
}
mpq_clear(q);
mpz_clear(z);
return str;
}
char * fmpq_poly_get_str_pretty(const fmpq_poly_t poly, const char * var)
{
return _fmpq_poly_get_str_pretty(poly->coeffs, poly->den, poly->length,
var);
}