185 lines
5.0 KiB
C
185 lines
5.0 KiB
C
/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2010, 2012 Sebastian Pancratz
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******************************************************************************/
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#include <stdlib.h>
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#include <stdio.h>
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#include "fmpq_poly.h"
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/*
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Macro wrapping _fmpq_fprint(file, x, y), ensuring that the printed
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rational is in lowest terms. Assumes that y > 0.
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*/
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#define __fmpq_fprint(x,y) \
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do { \
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fmpz_gcd(g, x, y); \
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if (fmpz_is_one(g)) \
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{ \
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_fmpq_fprint(file, x, y); \
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} \
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else \
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{ \
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fmpz_divexact(n, x, g); \
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fmpz_divexact(d, y, g); \
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_fmpq_fprint(file, n, d); \
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} \
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} while (0)
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/* checks if x/y == 1, where (x, y) need not be in lowest terms */
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#define __fmpq_is_one(x,y) fmpz_equal((x), (y))
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/* checks if x/y == +/- 1, where (x, y) need not be in lowest terms */
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#define __fmpq_is_pm1(x,y) (fmpz_cmpabs((x),(y)) == 0)
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int _fmpq_poly_fprint_pretty(FILE * file,
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const fmpz *poly, const fmpz_t den, slong len,
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const char * x)
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{
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fmpz_t n, d, g;
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fmpz_init(n);
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fmpz_init(d);
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fmpz_init(g);
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if (len == 0)
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{
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fputc('0', file);
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}
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else if (len == 1)
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{
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_fmpq_fprint(file, poly + 0, den);
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}
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else if (len == 2)
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{
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if (__fmpq_is_one(poly + 1, den))
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{
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flint_fprintf(file, "%s", x);
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}
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else if (__fmpq_is_pm1(poly + 1, den))
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{
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flint_fprintf(file, "-%s", x);
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}
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else
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{
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__fmpq_fprint(poly + 1, den);
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flint_fprintf(file, "*%s", x);
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}
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if (fmpz_sgn(poly + 0) > 0)
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{
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flint_fprintf(file, "+");
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__fmpq_fprint(poly + 0, den);
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}
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else if (fmpz_sgn(poly + 0) < 0)
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{
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__fmpq_fprint(poly + 0, den);
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}
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}
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else /* len >= 3 */
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{
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slong i = len - 1; /* i >= 2 */
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{
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if (__fmpq_is_one(poly + i, den))
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flint_fprintf(file, "%s^%wd", x, i);
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else if (__fmpq_is_pm1(poly + i, den))
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flint_fprintf(file, "-%s^%wd", x, i);
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else
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{
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__fmpq_fprint(poly + i, den);
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flint_fprintf(file, "*%s^%wd", x, i);
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}
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--i;
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}
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for (; i > 1; --i)
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{
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if (poly[i] == 0)
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continue;
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if (__fmpq_is_one(poly + i, den))
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flint_fprintf(file, "+%s^%wd", x, i);
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else if (__fmpq_is_pm1(poly + i, den))
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flint_fprintf(file, "-%s^%wd", x, i);
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else
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{
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if (fmpz_sgn(poly + i) > 0)
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{
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fputc('+', file);
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}
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__fmpq_fprint(poly + i, den);
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flint_fprintf(file, "*%s^%wd", x, i);
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}
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}
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if (poly[1])
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{
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if (__fmpq_is_one(poly + 1, den))
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{
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fputc('+', file);
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fputs(x, file);
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}
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else if (__fmpq_is_pm1(poly + 1, den))
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{
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fputc('-', file);
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fputs(x, file);
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}
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else
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{
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if (fmpz_sgn(poly + 1) > 0)
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{
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fputc('+', file);
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}
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__fmpq_fprint(poly + 1, den);
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fputc('*', file);
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fputs(x, file);
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}
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}
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if (*(poly))
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{
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if (fmpz_sgn(poly) > 0)
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{
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fputc('+', file);
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}
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__fmpq_fprint(poly + 0, den);
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}
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}
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fmpz_clear(n);
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fmpz_clear(d);
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fmpz_clear(g);
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return 1;
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}
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#undef __fmpq_fprint
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int fmpq_poly_fprint_pretty(FILE * file,
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const fmpq_poly_t poly, const char * var)
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{
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return _fmpq_poly_fprint_pretty(file, poly->coeffs, poly->den, poly->length, var);
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}
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