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Diffstat (limited to 'libtommath/bn_mp_n_root_ex.c')
-rw-r--r--libtommath/bn_mp_n_root_ex.c132
1 files changed, 0 insertions, 132 deletions
diff --git a/libtommath/bn_mp_n_root_ex.c b/libtommath/bn_mp_n_root_ex.c
deleted file mode 100644
index 079b4f3..0000000
--- a/libtommath/bn_mp_n_root_ex.c
+++ /dev/null
@@ -1,132 +0,0 @@
-#include <tommath_private.h>
-#ifdef BN_MP_N_ROOT_EX_C
-/* LibTomMath, multiple-precision integer library -- Tom St Denis
- *
- * LibTomMath is a library that provides multiple-precision
- * integer arithmetic as well as number theoretic functionality.
- *
- * The library was designed directly after the MPI library by
- * Michael Fromberger but has been written from scratch with
- * additional optimizations in place.
- *
- * The library is free for all purposes without any express
- * guarantee it works.
- *
- * Tom St Denis, tstdenis82@gmail.com, http://libtom.org
- */
-
-/* find the n'th root of an integer
- *
- * Result found such that (c)**b <= a and (c+1)**b > a
- *
- * This algorithm uses Newton's approximation
- * x[i+1] = x[i] - f(x[i])/f'(x[i])
- * which will find the root in log(N) time where
- * each step involves a fair bit. This is not meant to
- * find huge roots [square and cube, etc].
- */
-int mp_n_root_ex (mp_int * a, mp_digit b, mp_int * c, int fast)
-{
- mp_int t1, t2, t3;
- int res, neg;
-
- /* input must be positive if b is even */
- if (((b & 1) == 0) && (a->sign == MP_NEG)) {
- return MP_VAL;
- }
-
- if ((res = mp_init (&t1)) != MP_OKAY) {
- return res;
- }
-
- if ((res = mp_init (&t2)) != MP_OKAY) {
- goto LBL_T1;
- }
-
- if ((res = mp_init (&t3)) != MP_OKAY) {
- goto LBL_T2;
- }
-
- /* if a is negative fudge the sign but keep track */
- neg = a->sign;
- a->sign = MP_ZPOS;
-
- /* t2 = 2 */
- mp_set (&t2, 2);
-
- do {
- /* t1 = t2 */
- if ((res = mp_copy (&t2, &t1)) != MP_OKAY) {
- goto LBL_T3;
- }
-
- /* t2 = t1 - ((t1**b - a) / (b * t1**(b-1))) */
-
- /* t3 = t1**(b-1) */
- if ((res = mp_expt_d_ex (&t1, b - 1, &t3, fast)) != MP_OKAY) {
- goto LBL_T3;
- }
-
- /* numerator */
- /* t2 = t1**b */
- if ((res = mp_mul (&t3, &t1, &t2)) != MP_OKAY) {
- goto LBL_T3;
- }
-
- /* t2 = t1**b - a */
- if ((res = mp_sub (&t2, a, &t2)) != MP_OKAY) {
- goto LBL_T3;
- }
-
- /* denominator */
- /* t3 = t1**(b-1) * b */
- if ((res = mp_mul_d (&t3, b, &t3)) != MP_OKAY) {
- goto LBL_T3;
- }
-
- /* t3 = (t1**b - a)/(b * t1**(b-1)) */
- if ((res = mp_div (&t2, &t3, &t3, NULL)) != MP_OKAY) {
- goto LBL_T3;
- }
-
- if ((res = mp_sub (&t1, &t3, &t2)) != MP_OKAY) {
- goto LBL_T3;
- }
- } while (mp_cmp (&t1, &t2) != MP_EQ);
-
- /* result can be off by a few so check */
- for (;;) {
- if ((res = mp_expt_d_ex (&t1, b, &t2, fast)) != MP_OKAY) {
- goto LBL_T3;
- }
-
- if (mp_cmp (&t2, a) == MP_GT) {
- if ((res = mp_sub_d (&t1, 1, &t1)) != MP_OKAY) {
- goto LBL_T3;
- }
- } else {
- break;
- }
- }
-
- /* reset the sign of a first */
- a->sign = neg;
-
- /* set the result */
- mp_exch (&t1, c);
-
- /* set the sign of the result */
- c->sign = neg;
-
- res = MP_OKAY;
-
-LBL_T3:mp_clear (&t3);
-LBL_T2:mp_clear (&t2);
-LBL_T1:mp_clear (&t1);
- return res;
-}
-#endif
-
-/* ref: $Format:%D$ */
-/* git commit: $Format:%H$ */
-/* commit time: $Format:%ai$ */