unit tests for PYP sampler

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@620 ec762483-ff6d-05da-a07a-a48fb63a330f

4 files changed, 126 insertions, 39 deletions

diff --git a/gi/clda/src/Makefile.am b/gi/clda/src/Makefile.am
index 2b1393ac..6a76fc93 100644
--- a/gi/clda/src/Makefile.am
+++ b/gi/clda/src/Makefile.am
@@ -1,3 +1,14 @@
+if HAVE_GTEST
+noinst_PROGRAMS = \
+  crp_test
+
+TESTS = crp_test
+
+crp_test_SOURCES = crp_test.cc
+crp_test_LDADD = $(GTEST_LDFLAGS) $(GTEST_LIBS)
+
+endif
+
 bin_PROGRAMS = clda
 
 clda_SOURCES = clda.cc
diff --git a/gi/clda/src/ccrp.h b/gi/clda/src/ccrp.h
index 47f364f2..9b1c5284 100644
--- a/gi/clda/src/ccrp.h
+++ b/gi/clda/src/ccrp.h
@@ -18,12 +18,19 @@ class CCRP {
  public:
   CCRP(double disc, double conc) : num_tables_(), num_customers_(), discount_(disc), concentration_(conc) {}
 
+  void clear() {
+    num_tables_ = 0;
+    num_customers_ = 0;
+    dish_locs_.clear();
+  }
+
   unsigned num_tables(const Dish& dish) const {
     const typename std::tr1::unordered_map<Dish, DishLocations, DishHash>::const_iterator it = dish_locs_.find(dish);
     if (it == dish_locs_.end()) return 0;
     return it->second.table_counts_.size();
   }
 
+  // returns +1 or 0 indicating whether a new table was opened
   int increment(const Dish& dish, const double& p0, MT19937* rng) {
     DishLocations& loc = dish_locs_[dish];
     bool share_table = false;
@@ -56,6 +63,7 @@ class CCRP {
     return (share_table ? 0 : 1);
   }
 
+  // returns -1 or 0, indicating whether a table was closed
   int decrement(const Dish& dish, MT19937* rng) {
     DishLocations& loc = dish_locs_[dish];
     assert(loc.total_dish_count_);
@@ -66,11 +74,13 @@ class CCRP {
       return -1;
     } else {
       int delta = 0;
-      double r = rng->next() * (loc.total_dish_count_ - loc.table_counts_.size() * discount_);
+      // sample customer to remove UNIFORMLY. that is, do NOT use the discount
+      // here. if you do, it will introduce (unwanted) bias!
+      double r = rng->next() * loc.total_dish_count_;
       --loc.total_dish_count_;
       for (typename std::list<unsigned>::iterator ti = loc.table_counts_.begin();
            ti != loc.table_counts_.end(); ++ti) {
-        r -= (*ti - discount_);
+        r -= *ti;
         if (r <= 0.0) {
           if ((--(*ti)) == 0) {
             --num_tables_;
@@ -107,7 +117,9 @@ class CCRP {
     double lp = 0.0;
     if (num_customers_) {
       const double r = lgamma(1.0 - discount_);
-      lp = lgamma(concentration_) - lgamma(concentration_ + num_customers_) + num_tables_ * discount_ + lgamma(concentration_ / discount_ + num_tables_) - lgamma(concentration_ / discount_);
+      lp = lgamma(concentration_) - lgamma(concentration_ + num_customers_)
+           + num_tables_ * discount_ + lgamma(concentration_ / discount_ + num_tables_)
+           - lgamma(concentration_ / discount_);
       for (typename std::tr1::unordered_map<Dish, DishLocations, DishHash>::const_iterator it = dish_locs_.begin();
            it != dish_locs_.end(); ++it) {
         const DishLocations& cur = it->second;
@@ -119,8 +131,9 @@ class CCRP {
 
   struct DishLocations {
     DishLocations() : total_dish_count_() {}
-    unsigned total_dish_count_;
+    unsigned total_dish_count_;        // customers at all tables with this dish
     std::list<unsigned> table_counts_; // list<> gives O(1) deletion and insertion, which we want
+                                       // .size() is the number of tables for this dish
   };
 
   void Print(std::ostream* out) const {
diff --git a/gi/clda/src/clda.cc b/gi/clda/src/clda.cc
index 0232331b..10056bc9 100644
--- a/gi/clda/src/clda.cc
+++ b/gi/clda/src/clda.cc
@@ -25,39 +25,7 @@ void ShowTopWordsForTopic(const map<WordID, int>& counts) {
   cerr << endl;
 }
 
-void tc() {
-  MT19937 rng;
-  CCRP<string> crp(0.1, 5);
-  double un = 0.25;
-  int tt = 0;
-  tt += crp.increment("hi", un, &rng);
-  tt += crp.increment("foo", un, &rng);
-  tt += crp.increment("bar", un, &rng);
-  tt += crp.increment("bar", un, &rng);
-  tt += crp.increment("bar", un, &rng);
-  tt += crp.increment("bar", un, &rng);
-  tt += crp.increment("bar", un, &rng);
-  tt += crp.increment("bar", un, &rng);
-  tt += crp.increment("bar", un, &rng);
-  cout << "tt=" << tt << endl;
-  cout << crp << endl;
-  cout << "  P(bar)=" << crp.prob("bar", un) << endl;
-  cout << "  P(hi)=" << crp.prob("hi", un) << endl;
-  cout << "  P(baz)=" << crp.prob("baz", un) << endl;
-  cout << "  P(foo)=" << crp.prob("foo", un) << endl;
-  double x = crp.prob("bar", un) + crp.prob("hi", un) + crp.prob("baz", un) + crp.prob("foo", un);
-  cout << "    tot=" << x << endl;
-  tt += crp.decrement("hi", &rng);
-  tt += crp.decrement("bar", &rng);
-  cout << crp << endl;
-  tt += crp.decrement("bar", &rng);
-  cout << crp << endl;
-  cout << "tt=" << tt << endl;
-  cout << crp.log_crp_prob() << endl;
-}
-
 int main(int argc, char** argv) {
-  tc();
   if (argc != 3) {
     cerr << "Usage: " << argv[0] << " num-classes num-samples\n";
     return 1;
@@ -88,11 +56,11 @@ int main(int argc, char** argv) {
   MT19937 rng;
   cerr << "INITIALIZING RANDOM TOPIC ASSIGNMENTS\n";
   zji.resize(wji.size());
-  double disc = 0.05;
+  double disc = 0.1;
   double beta = 10.0;
   double alpha = 50.0;
-  double uniform_topic = 1.0 / num_classes;
-  double uniform_word = 1.0 / TD::NumWords();
+  const double uniform_topic = 1.0 / num_classes;
+  const double uniform_word = 1.0 / TD::NumWords();
   vector<CCRP<int> > dr(zji.size(), CCRP<int>(disc, beta)); // dr[i] describes the probability of using a topic in document i
   vector<CCRP<int> > wr(num_classes, CCRP<int>(disc, alpha)); // wr[k] describes the probability of generating a word in topic k
   for (int j = 0; j < zji.size(); ++j) {
diff --git a/gi/clda/src/crp_test.cc b/gi/clda/src/crp_test.cc
new file mode 100644
index 00000000..750d80a7
--- /dev/null
+++ b/gi/clda/src/crp_test.cc
@@ -0,0 +1,95 @@
+#include <iostream>
+#include <vector>
+#include <string>
+
+#include <gtest/gtest.h>
+
+#include "ccrp.h"
+#include "sampler.h"
+
+const size_t MAX_DOC_LEN_CHARS = 10000000;
+
+using namespace std;
+
+class CRPTest : public testing::Test {
+ public:
+  CRPTest() {}
+ protected:
+  virtual void SetUp() { }
+  virtual void TearDown() { }
+  MT19937 rng;
+};
+
+TEST_F(CRPTest, Dist) {
+  CCRP<string> crp(0.1, 5);
+  double un = 0.25;
+  int tt = 0;
+  tt += crp.increment("hi", un, &rng);
+  tt += crp.increment("foo", un, &rng);
+  tt += crp.increment("bar", un, &rng);
+  tt += crp.increment("bar", un, &rng);
+  tt += crp.increment("bar", un, &rng);
+  tt += crp.increment("bar", un, &rng);
+  tt += crp.increment("bar", un, &rng);
+  tt += crp.increment("bar", un, &rng);
+  tt += crp.increment("bar", un, &rng);
+  cout << "tt=" << tt << endl;
+  cout << crp << endl;
+  cout << "  P(bar)=" << crp.prob("bar", un) << endl;
+  cout << "  P(hi)=" << crp.prob("hi", un) << endl;
+  cout << "  P(baz)=" << crp.prob("baz", un) << endl;
+  cout << "  P(foo)=" << crp.prob("foo", un) << endl;
+  double x = crp.prob("bar", un) + crp.prob("hi", un) + crp.prob("baz", un) + crp.prob("foo", un);
+  cout << "    tot=" << x << endl;
+  EXPECT_FLOAT_EQ(1.0, x);
+  tt += crp.decrement("hi", &rng);
+  tt += crp.decrement("bar", &rng);
+  cout << crp << endl;
+  tt += crp.decrement("bar", &rng);
+  cout << crp << endl;
+  cout << "tt=" << tt << endl;
+}
+
+TEST_F(CRPTest, Exchangability) {
+    double tot = 0;
+    double xt = 0;
+    CCRP<int> crp(0.5, 1.0);
+    int cust = 10;
+    vector<int> hist(cust + 1, 0);
+    for (int i = 0; i < cust; ++i) { crp.increment(1, 1.0, &rng); }
+    const int samples = 100000;
+    const bool simulate = true;
+    for (int k = 0; k < samples; ++k) {
+      if (!simulate) {
+        crp.clear();
+        for (int i = 0; i < cust; ++i) { crp.increment(1, 1.0, &rng); }
+      } else {
+        int da = rng.next() * cust;
+        bool a = rng.next() < 0.5;
+        if (a) {
+          for (int i = 0; i < da; ++i) { crp.increment(1, 1.0, &rng); }
+          for (int i = 0; i < da; ++i) { crp.decrement(1, &rng); }
+          xt += 1.0;
+        } else {
+          for (int i = 0; i < da; ++i) { crp.decrement(1, &rng); }
+          for (int i = 0; i < da; ++i) { crp.increment(1, 1.0, &rng); }
+        }
+      }
+      int c = crp.num_tables(1);
+      ++hist[c];
+      tot += c;
+    }
+    cerr << "P(a) = " << (xt / samples) << endl;
+    cerr << "E[num tables] = " << (tot / samples) << endl;
+    double error = fabs((tot / samples) - 5.4);
+    cerr << "  error = " << error << endl;
+    EXPECT_LT(error, 0.1);  // it's possible for this to fail, but
+                            // very, very unlikely
+    for (int i = 1; i <= cust; ++i)
+      cerr << i << ' ' << (hist[i]) << endl;
+}
+
+int main(int argc, char** argv) {
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}