X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Futils.h;h=7018bc9511a02584ffb885b81bf0cffb9d183a1b;hp=edde75fcde3ff071cd7e8ed4b88bcfc9a6840d99;hb=af0c47009ca7a15af966430bdf1a72fe05c1c6f9;hpb=9eab44408b9213d8909b7a9e525f404ad06064dd diff --git a/ginac/utils.h b/ginac/utils.h index edde75fc..7018bc95 100644 --- a/ginac/utils.h +++ b/ginac/utils.h @@ -1,9 +1,10 @@ /** @file utils.h * - * Interface to several small and furry utilities. */ + * Interface to several small and furry utilities needed within GiNaC but not + * of any interest to the user of the library. */ /* - * GiNaC Copyright (C) 1999 Johannes Gutenberg University Mainz, Germany + * GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -26,20 +27,68 @@ #include #include #include "config.h" +#include "assertion.h" +#ifndef NO_NAMESPACE_GINAC namespace GiNaC { +#endif // ndef NO_NAMESPACE_GINAC template -string ToString(T const & t) +string ToString(const T & t) { char buf[256]; ostrstream(buf,sizeof(buf)) << t << ends; return buf; } +/** Exception thrown by classes which provide their own series expansion to + * signal that ordinary Taylor expansion is safe. */ +class do_taylor {}; + unsigned log2(unsigned n); -int compare_pointers(void const * a, void const * b); +int compare_pointers(const void * a, const void * b); + +/** Rotate lower 31 bits of unsigned value by one bit to the left + * (upper bits get cleared). */ +inline unsigned rotate_left_31(unsigned n) +{ + // clear highest bit and shift 1 bit to the left + n=(n & 0x7FFFFFFFU) << 1; + + // overflow? clear highest bit and set lowest bit + if (n & 0x80000000U) { + n=(n & 0x7FFFFFFFU) | 0x00000001U; + } + GINAC_ASSERT(n<0x80000000U); + + return n; +} + +/** Golden ratio hash function. */ +inline unsigned golden_ratio_hash(unsigned n) +{ + // This function requires arithmetic with at least 64 significant bits +#if SIZEOF_LONG_DOUBLE > 8 + // If "long double" is bigger than 64 bits, we assume that the mantissa + // has at least 64 bits. This is not guaranteed but it's a good guess. + const static long double golden_ratio = .618033988749894848204586834370; + long double m = golden_ratio * n; + return unsigned((m - int(m)) * 0x80000000); +#elif SIZEOF_LONG >= 8 + // "long" has 64 bits, so we prefer it because it might be more efficient + // than "long long" + unsigned long l = n * 0x4f1bbcddL; + return (l & 0x7fffffffU) ^ (l >> 32); +#elif SIZEOF_LONG_LONG >= 8 + // This requires ´long long´ (or an equivalent 64 bit type)---which is, + // unfortunately, not ANSI-compliant: + unsigned long long l = n * 0x4f1bbcddLL; + return (l & 0x7fffffffU) ^ (l >> 32); +#else +#error "No 64 bit data type. You lose." +#endif +} // modified from stl_algo.h: always do com(*first1,*first2) instead of comp(*first2,*first1) template +int permutation_sign(vector s) +{ + if (s.size() < 2) + return 0; + int sigma = 1; + for (typename vector::iterator i=s.begin(); i!=s.end()-1; ++i) { + for (typename vector::iterator j=i+1; j!=s.end(); ++j) { + if (*i == *j) + return 0; + if (*i > *j) { + iter_swap(i,j); + sigma = -sigma; + } + } + } + return sigma; +} + +// Collection of `construct on first use' wrappers for safely avoiding +// internal object replication without running into the `static +// initialization order fiasco'. This chest of numbers helps speed up +// the library but should not be used outside it since it is +// potentially confusing. + +class numeric; +class ex; + +const numeric & _num_120(void); // -120 +const ex & _ex_120(void); +const numeric & _num_60(void); // -60 +const ex & _ex_60(void); +const numeric & _num_30(void); // -30 +const ex & _ex_30(void); +const numeric & _num_25(void); // -25 +const ex & _ex_25(void); +const numeric & _num_24(void); // -24 +const ex & _ex_24(void); +const numeric & _num_20(void); // -20 +const ex & _ex_20(void); +const numeric & _num_18(void); // -18 +const ex & _ex_18(void); +const numeric & _num_15(void); // -15 +const ex & _ex_15(void); +const numeric & _num_12(void); // -12 +const ex & _ex_12(void); +const numeric & _num_11(void); // -11 +const ex & _ex_11(void); +const numeric & _num_10(void); // -10 +const ex & _ex_10(void); +const numeric & _num_9(void); // -9 +const ex & _ex_9(void); +const numeric & _num_8(void); // -8 +const ex & _ex_8(void); +const numeric & _num_7(void); // -7 +const ex & _ex_7(void); +const numeric & _num_6(void); // -6 +const ex & _ex_6(void); +const numeric & _num_5(void); // -5 +const ex & _ex_5(void); +const numeric & _num_4(void); // -4 +const ex & _ex_4(void); +const numeric & _num_3(void); // -3 +const ex & _ex_3(void); +const numeric & _num_2(void); // -2 +const ex & _ex_2(void); +const numeric & _num_1(void); // -1 +const ex & _ex_1(void); +const numeric & _num_1_2(void); // -1/2 +const ex & _ex_1_2(void); +const numeric & _num_1_3(void); // -1/3 +const ex & _ex_1_3(void); +const numeric & _num_1_4(void); // -1/4 +const ex & _ex_1_4(void); +const numeric & _num0(void); // 0 +const ex & _ex0(void); +const numeric & _num1_4(void); // 1/4 +const ex & _ex1_4(void); +const numeric & _num1_3(void); // 1/3 +const ex & _ex1_3(void); +const numeric & _num1_2(void); // 1/2 +const ex & _ex1_2(void); +const numeric & _num1(void); // 1 +const ex & _ex1(void); +const numeric & _num2(void); // 2 +const ex & _ex2(void); +const numeric & _num3(void); // 3 +const ex & _ex3(void); +const numeric & _num4(void); // 4 +const ex & _ex4(void); +const numeric & _num5(void); // 5 +const ex & _ex5(void); +const numeric & _num6(void); // 6 +const ex & _ex6(void); +const numeric & _num7(void); // 7 +const ex & _ex7(void); +const numeric & _num8(void); // 8 +const ex & _ex8(void); +const numeric & _num9(void); // 9 +const ex & _ex9(void); +const numeric & _num10(void); // 10 +const ex & _ex10(void); +const numeric & _num11(void); // 11 +const ex & _ex11(void); +const numeric & _num12(void); // 12 +const ex & _ex12(void); +const numeric & _num15(void); // 15 +const ex & _ex15(void); +const numeric & _num18(void); // 18 +const ex & _ex18(void); +const numeric & _num20(void); // 20 +const ex & _ex20(void); +const numeric & _num24(void); // 24 +const ex & _ex24(void); +const numeric & _num25(void); // 25 +const ex & _ex25(void); +const numeric & _num30(void); // 30 +const ex & _ex30(void); +const numeric & _num60(void); // 60 +const ex & _ex60(void); +const numeric & _num120(void); // 120 +const ex & _ex120(void); + +#ifndef NO_NAMESPACE_GINAC } // namespace GiNaC +#endif // ndef NO_NAMESPACE_GINAC #endif // ndef __GINAC_UTILS_H__