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-rw-r--r--utils/max_plus.h201
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diff --git a/utils/max_plus.h b/utils/max_plus.h
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--- a/utils/max_plus.h
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-#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