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Diffstat (limited to 'utils/max_plus.h')
-rw-r--r-- | utils/max_plus.h | 201 |
1 files changed, 0 insertions, 201 deletions
diff --git a/utils/max_plus.h b/utils/max_plus.h deleted file mode 100644 index 2e56f85e..00000000 --- a/utils/max_plus.h +++ /dev/null @@ -1,201 +0,0 @@ -#ifndef MAX_PLUS_H_ -#define MAX_PLUS_H_ - -#define MAX_PLUS_ORDER 0 -#define MAX_PLUS_DEBUG(x) - -// max-plus algebra. ordering a > b really means that (i.e. default a<b sorting will do worst (closest to 0) first. so get used to passing predicates like std::greater<MaxPlus<T> > around -// x+y := max{x,y} -// x*y := x+y -// 0 := -inf -// 1 := 0 -// additive inverse does not, but mult. does. (inverse()) and x/y := x-y = x+y.inverse() -//WARNING: default order is reversed, on purpose, i.e. a<b means a "better than" b, i.e. log(p_a)>log(p_b). sorry. defaults in libs are to order ascending, but we want best first. - -#include <boost/functional/hash.hpp> -#include <iostream> -#include <cstdlib> -#include <cmath> -#include <cassert> -#include <limits> -#include "semiring.h" -#include "show.h" -//#include "logval.h" - -template <class T> -class MaxPlus { - public: - void print(std::ostream &o) const { - o<<v_; - } - PRINT_SELF(MaxPlus<T>) - template <class O> - void operator=(O const& o) { - v_=o.v_; - } - template <class O> - MaxPlus(O const& o) : v_(o.v_) { } - - typedef MaxPlus<T> Self; - MaxPlus() : v_(LOGVAL_LOG0) {} - explicit MaxPlus(double x) : v_(std::log(x)) {} - MaxPlus(init_1) : v_(0) { } - MaxPlus(init_0) : v_(LOGVAL_LOG0) { } - MaxPlus(int x) : v_(std::log(x)) {} - MaxPlus(unsigned x) : v_(std::log(x)) { } - MaxPlus(double lnx,bool sign) : v_(lnx) { MAX_PLUS_DEBUG(assert(!sign)); } - MaxPlus(double lnx,init_lnx) : v_(lnx) {} - static Self exp(T lnx) { return MaxPlus(lnx,false); } - - // maybe the below are faster than == 1 and == 0. i don't know. - bool is_1() const { return v_==0; } - bool is_0() const { return v_==LOGVAL_LOG0; } - - static Self One() { return Self(init_1()); } - static Self Zero() { return Self(init_0()); } - static Self e() { return Self(1,false); } - void logeq(const T& v) { v_ = v; } - bool signbit() const { return false; } - - Self& logpluseq(const Self& a) { - if (a.is_0()) return *this; - if (a.v_ < v_) { - v_ = v_ + log1p(std::exp(a.v_ - v_)); - } else { - v_ = a.v_ + log1p(std::exp(v_ - a.v_)); - } - return *this; - } - - Self& besteq(const Self& a) { - if (a.v_ < v_) - v_=a.v_; - return *this; - } - - Self& operator+=(const Self& a) { - if (a.v_ < v_) - v_=a.v_; - return *this; - } - - Self& operator*=(const Self& a) { - v_ += a.v_; - return *this; - } - - Self& operator/=(const Self& a) { - v_ -= a.v_; - return *this; - } - - // Self(fabs(log(x)),x.s_) - friend Self abslog(Self x) { - if (x.v_<0) x.v_=-x.v_; - return x; - } - - Self& poweq(const T& power) { - v_ *= power; - return *this; - } - - Self inverse() const { - return Self(-v_,false); - } - - Self pow(const T& power) const { - Self res = *this; - res.poweq(power); - return res; - } - - Self root(const T& root) const { - return pow(1/root); - } - -// copy elision - as opposed to explicit copy of Self const& o1, we should be able to construct Logval r=a+(b+c) as a single result in place in r. todo: return std::move(o1) - C++0x - friend inline Self operator+(Self a,Self const& b) { - a+=b; - return a; - } - friend inline Self operator*(Self a,Self const& b) { - a*=b; - return a; - } - friend inline Self operator/(Self a,Self const& b) { - a/=b; - return a; - } - friend inline T log(Self const& a) { - return a.v_; - } - friend inline T pow(Self const& a,T const& e) { - return a.pow(e); - } - - // intentionally not defining an operator < or operator > - because you may want to default (for library convenience) a<b means a better than b (i.e. gt) - inline bool lt(Self const& o) const { - return v_ < o.v_; - } - inline bool gt(Self const& o) const { - return o.v_ > v_; - } - friend inline bool operator==(Self const& lhs, Self const& rhs) { - return lhs.v_ == rhs.v_; - } - friend inline bool operator!=(Self const& lhs, Self const& rhs) { - return lhs.v_ != rhs.v_; - } - std::size_t hash() const { - using namespace boost; - return hash_value(v_); - } - friend inline std::size_t hash_value(Self const& x) { - return x.hash(); - } - -/* - operator T() const { - return std::exp(v_); - } -*/ - T as_float() const { - return std::exp(v_); - } - - T v_; -}; - -template <class T> -struct semiring_traits<MaxPlus<T> > : default_semiring_traits<MaxPlus<T> > { - static const bool has_logplus=true; - static const bool has_besteq=true; -#if MAX_PLUS_ORDER - static const bool have_order=true; -#endif -}; - -#if MAX_PLUS_ORDER -template <class T> -bool operator<(const MaxPlus<T>& lhs, const MaxPlus<T>& rhs) { - return (lhs.v_ < rhs.v_); -} - -template <class T> -bool operator<=(const MaxPlus<T>& lhs, const MaxPlus<T>& rhs) { - return (lhs.v_ <= rhs.v_); -} - -template <class T> -bool operator>(const MaxPlus<T>& lhs, const MaxPlus<T>& rhs) { - return (lhs.v_ > rhs.v_); -} - -template <class T> -bool operator>=(const MaxPlus<T>& lhs, const MaxPlus<T>& rhs) { - return (lhs.v_ >= rhs.v_); -} -#endif - -#endif |