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Unified Diff: Modules/_decimal/libmpdec/numbertheory.c

Issue 7652: Merge C version of decimal into py3k.
Patch Set: Created 7 years, 8 months ago
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/Modules/_decimal/libmpdec/numbertheory.c Sat Mar 10 18:12:20 2012 +0100
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2008-2010 Stefan Krah. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+
+#include "mpdecimal.h"
+#include <stdlib.h>
+#include <assert.h>
+#include "bits.h"
+#include "umodarith.h"
+#include "numbertheory.h"
+
+
+/* Bignum: Initialize the Number Theoretic Transform. */
+
+
+/*
+ * Return the nth root of unity in F(p). This corresponds to e**((2*pi*i)/n)
+ * in the Fourier transform. We have w**n == 1 (mod p).
+ * n := transform length.
+ * sign := -1 for forward transform, 1 for backward transform.
+ * modnum := one of {P1, P2, P3}.
+ */
+mpd_uint_t
+_mpd_getkernel(mpd_uint_t n, int sign, int modnum)
+{
+ mpd_uint_t umod, p, r, xi;
+#ifdef PPRO
+ double dmod;
+ uint32_t dinvmod[3];
+#endif
+
+ SETMODULUS(modnum);
+ r = mpd_roots[modnum]; /* primitive root of F(p) */
+ p = umod;
+ xi = (p-1) / n;
+
+ if (sign == -1)
+ return POWMOD(r, (p-1-xi));
+ else
+ return POWMOD(r, xi);
+}
+
+/*
+ * Initialize and return transform parameters.
+ * n := transform length.
+ * sign := -1 for forward transform, 1 for backward transform.
+ * modnum := one of {P1, P2, P3}.
+ */
+struct fnt_params *
+_mpd_init_fnt_params(mpd_size_t n, int sign, int modnum)
+{
+ struct fnt_params *tparams;
+ mpd_uint_t umod;
+#ifdef PPRO
+ double dmod;
+ uint32_t dinvmod[3];
+#endif
+ mpd_uint_t kernel, w;
+ mpd_uint_t i;
+ mpd_size_t nhalf;
+
+ assert(ispower2(n));
+ assert(sign == -1 || sign == 1);
+ assert(P1 <= modnum && modnum <= P3);
+
+ nhalf = n/2;
+ tparams = mpd_sh_alloc(sizeof *tparams, nhalf, sizeof (mpd_uint_t));
+ if (tparams == NULL) {
+ return NULL;
+ }
+
+ SETMODULUS(modnum);
+ kernel = _mpd_getkernel(n, sign, modnum);
+
+ tparams->modnum = modnum;
+ tparams->modulus = umod;
+ tparams->kernel = kernel;
+
+ /* wtable[] := w**0, w**1, ..., w**(nhalf-1) */
+ w = 1;
+ for (i = 0; i < nhalf; i++) {
+ tparams->wtable[i] = w;
+ w = MULMOD(w, kernel);
+ }
+
+ return tparams;
+}
+
+/* Initialize wtable of size three. */
+void
+_mpd_init_w3table(mpd_uint_t w3table[3], int sign, int modnum)
+{
+ mpd_uint_t umod;
+#ifdef PPRO
+ double dmod;
+ uint32_t dinvmod[3];
+#endif
+ mpd_uint_t kernel;
+
+ SETMODULUS(modnum);
+ kernel = _mpd_getkernel(3, sign, modnum);
+
+ w3table[0] = 1;
+ w3table[1] = kernel;
+ w3table[2] = POWMOD(kernel, 2);
+}
+
+
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