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authorChris Dyer <cdyer@cs.cmu.edu>2012-03-05 16:06:45 -0500
committerChris Dyer <cdyer@cs.cmu.edu>2012-03-05 16:06:45 -0500
commit2048ac9943e2695a75b5f0303ca869e66ee32202 (patch)
tree35de13bff0ce7f1fde619d04d165f7e6ac5b0631 /utils/mfcr.h
parentce58cb44771a5194b71682d1602abe2fef9e6f13 (diff)
use template parameter inference to figure out what type to use for probability computations, templatatize number of floors in MFCR rather than compile-time set
Diffstat (limited to 'utils/mfcr.h')
-rw-r--r--utils/mfcr.h68
1 files changed, 36 insertions, 32 deletions
diff --git a/utils/mfcr.h b/utils/mfcr.h
index aeaf599d..6cc0ebf1 100644
--- a/utils/mfcr.h
+++ b/utils/mfcr.h
@@ -8,6 +8,7 @@
#include <list>
#include <iostream>
#include <vector>
+#include <iterator>
#include <tr1/unordered_map>
#include <boost/functional/hash.hpp>
#include "sampler.h"
@@ -35,12 +36,11 @@ std::ostream& operator<<(std::ostream& o, const TableCount& tc) {
// referenced therein.
// http://www.aclweb.org/anthology/P/P09/P09-2085.pdf
//
-template <typename Dish, typename DishHash = boost::hash<Dish> >
+template <unsigned Floors, typename Dish, typename DishHash = boost::hash<Dish> >
class MFCR {
public:
- MFCR(unsigned num_floors, double d, double strength) :
- num_floors_(num_floors),
+ MFCR(double d, double strength) :
num_tables_(),
num_customers_(),
discount_(d),
@@ -50,8 +50,7 @@ class MFCR {
strength_prior_shape_(std::numeric_limits<double>::quiet_NaN()),
strength_prior_rate_(std::numeric_limits<double>::quiet_NaN()) {}
- MFCR(unsigned num_floors, double discount_strength, double discount_beta, double strength_shape, double strength_rate, double d = 0.9, double strength = 10.0) :
- num_floors_(num_floors),
+ MFCR(double discount_strength, double discount_beta, double strength_shape, double strength_rate, double d = 0.9, double strength = 10.0) :
num_tables_(),
num_customers_(),
discount_(d),
@@ -111,22 +110,22 @@ class MFCR {
}
// returns (delta, floor) indicating whether a new table (delta) was opened and on which floor
- TableCount increment(const Dish& dish, const std::vector<double>& p0s, const std::vector<double>& lambdas, MT19937* rng) {
- assert(p0s.size() == num_floors_);
- assert(lambdas.size() == num_floors_);
-
+ template <class InputIterator, class InputIterator2>
+ TableCount increment(const Dish& dish, InputIterator p0s, InputIterator2 lambdas, MT19937* rng) {
DishLocations& loc = dish_locs_[dish];
// marg_p0 = marginal probability of opening a new table on any floor with label dish
- const double marg_p0 = std::inner_product(p0s.begin(), p0s.end(), lambdas.begin(), 0.0);
- assert(marg_p0 <= 1.0);
+ typedef typename std::iterator_traits<InputIterator>::value_type F;
+ const F marg_p0 = std::inner_product(p0s, p0s + Floors, lambdas, F(0.0));
+ assert(marg_p0 <= F(1.0001));
int floor = -1;
bool share_table = false;
if (loc.total_dish_count_) {
- const double p_empty = (strength_ + num_tables_ * discount_) * marg_p0;
- const double p_share = (loc.total_dish_count_ - loc.table_counts_.size() * discount_);
+ const F p_empty = F(strength_ + num_tables_ * discount_) * marg_p0;
+ const F p_share = F(loc.total_dish_count_ - loc.table_counts_.size() * discount_);
share_table = rng->SelectSample(p_empty, p_share);
}
if (share_table) {
+ // this can be done with doubles since P0 (which may be tiny) is not involved
double r = rng->next() * (loc.total_dish_count_ - loc.table_counts_.size() * discount_);
for (typename std::list<TableCount>::iterator ti = loc.table_counts_.begin();
ti != loc.table_counts_.end(); ++ti) {
@@ -143,12 +142,18 @@ class MFCR {
assert(r <= 0.0);
}
} else { // sit at currently empty table -- must sample what floor
- double r = rng->next() * marg_p0;
- for (unsigned i = 0; i < p0s.size(); ++i) {
- r -= p0s[i] * lambdas[i];
- if (r <= 0.0) {
- floor = i;
- break;
+ if (Floors == 1) {
+ floor = 0;
+ } else {
+ F r = F(rng->next()) * marg_p0;
+ for (unsigned i = 0; i < Floors; ++i) {
+ r -= (*p0s) * (*lambdas);
+ ++p0s;
+ ++lambdas;
+ if (r <= F(0.0)) {
+ floor = i;
+ break;
+ }
}
}
assert(floor >= 0);
@@ -200,18 +205,18 @@ class MFCR {
return TableCount(delta, floor);
}
- double prob(const Dish& dish, const std::vector<double>& p0s, const std::vector<double>& lambdas) const {
- assert(p0s.size() == num_floors_);
- assert(lambdas.size() == num_floors_);
- const double marg_p0 = std::inner_product(p0s.begin(), p0s.end(), lambdas.begin(), 0.0);
- assert(marg_p0 <= 1.0);
+ template <class InputIterator, class InputIterator2>
+ typename std::iterator_traits<InputIterator>::value_type prob(const Dish& dish, InputIterator p0s, InputIterator2 lambdas) const {
+ typedef typename std::iterator_traits<InputIterator>::value_type F;
+ const F marg_p0 = std::inner_product(p0s, p0s + Floors, lambdas, F(0.0));
+ assert(marg_p0 <= F(1.0001));
const typename std::tr1::unordered_map<Dish, DishLocations, DishHash>::const_iterator it = dish_locs_.find(dish);
- const double r = num_tables_ * discount_ + strength_;
+ const F r = F(num_tables_ * discount_ + strength_);
if (it == dish_locs_.end()) {
- return r * marg_p0 / (num_customers_ + strength_);
+ return r * marg_p0 / F(num_customers_ + strength_);
} else {
- return (it->second.total_dish_count_ - discount_ * it->second.table_counts_.size() + r * marg_p0) /
- (num_customers_ + strength_);
+ return (F(it->second.total_dish_count_ - discount_ * it->second.table_counts_.size()) + F(r * marg_p0)) /
+ F(num_customers_ + strength_);
}
}
@@ -303,7 +308,7 @@ class MFCR {
};
void Print(std::ostream* out) const {
- (*out) << "MFCR(d=" << discount_ << ",strength=" << strength_ << ") customers=" << num_customers_ << std::endl;
+ (*out) << "MFCR<" << Floors << ">(d=" << discount_ << ",strength=" << strength_ << ") customers=" << num_customers_ << std::endl;
for (typename std::tr1::unordered_map<Dish, DishLocations, DishHash>::const_iterator it = dish_locs_.begin();
it != dish_locs_.end(); ++it) {
(*out) << it->first << " (" << it->second.total_dish_count_ << " on " << it->second.table_counts_.size() << " tables): ";
@@ -323,7 +328,6 @@ class MFCR {
return dish_locs_.end();
}
- unsigned num_floors_;
unsigned num_tables_;
unsigned num_customers_;
std::tr1::unordered_map<Dish, DishLocations, DishHash> dish_locs_;
@@ -340,8 +344,8 @@ class MFCR {
double strength_prior_rate_;
};
-template <typename T,typename H>
-std::ostream& operator<<(std::ostream& o, const MFCR<T,H>& c) {
+template <unsigned N,typename T,typename H>
+std::ostream& operator<<(std::ostream& o, const MFCR<N,T,H>& c) {
c.Print(&o);
return o;
}