Fix bugs for conditional sampling

ctgan/data_sampler.py

@@ -71,6 +71,8 @@ def is_discrete_column(column_info):
                 self._discrete_column_category_prob[current_id, :span_info.dim] = category_prob
                 self._discrete_column_cond_st[current_id] = current_cond_st
                 self._discrete_column_n_category[current_id] = span_info.dim
+                self._discrete_column_matrix_st[current_id] = st
+
                 current_cond_st += span_info.dim
                 current_id += 1
                 st = ed
@@ -150,7 +152,7 @@ def dim_cond_vec(self):
     def generate_cond_from_condition_column_info(self, condition_info, batch):
         """Generate the condition vector."""
         vec = np.zeros((batch, self._n_categories), dtype='float32')
-        id_ = self._discrete_column_matrix_st[condition_info['discrete_column_id']]
+        id_ = self._discrete_column_cond_st[condition_info['discrete_column_id']]
         id_ += condition_info['value_id']
         vec[:, id_] = 1
         return vec

ctgan/synthesizers/ctgan.py

@@ -440,6 +440,8 @@ def sample(self, n, condition_column=None, condition_value=None):
         Returns:
             numpy.ndarray or pandas.DataFrame
         """
+        self._generator.eval()
+
         if condition_column is not None and condition_value is not None:
             condition_info = self._transformer.convert_column_name_value_to_id(
                 condition_column, condition_value)
@@ -467,8 +469,10 @@ def sample(self, n, condition_column=None, condition_value=None):
                 c1 = torch.from_numpy(c1).to(self._device)
                 fakez = torch.cat([fakez, c1], dim=1)
 
-            fake = self._generator(fakez)
-            fakeact = self._apply_activate(fake)
+            with torch.no_grad():
+                fake = self._generator(fakez)
+                fakeact = self._apply_activate(fake)
+
             data.append(fakeact.detach().cpu().numpy())
 
         data = np.concatenate(data, axis=0)

tests/integration/synthesizer/test_ctgan.py

@@ -80,19 +80,19 @@ def test_log_frequency():
 
     discrete_columns = ['discrete']
 
-    ctgan = CTGANSynthesizer(epochs=100)
+    ctgan = CTGANSynthesizer(epochs=1)
     ctgan.fit(data, discrete_columns)
 
-    sampled = ctgan.sample(10000)
-    counts = sampled['discrete'].value_counts()
-    assert counts['a'] < 6500
+    assert ctgan._data_sampler._discrete_column_category_prob[0][0] < 0.95
+    assert ctgan._data_sampler._discrete_column_category_prob[0][1] > 0.025
+    assert ctgan._data_sampler._discrete_column_category_prob[0][2] > 0.025
 
-    ctgan = CTGANSynthesizer(log_frequency=False, epochs=100)
+    ctgan = CTGANSynthesizer(log_frequency=False, epochs=1)
     ctgan.fit(data, discrete_columns)
 
-    sampled = ctgan.sample(10000)
-    counts = sampled['discrete'].value_counts()
-    assert counts['a'] > 9000
+    assert ctgan._data_sampler._discrete_column_category_prob[0][0] == 0.95
+    assert ctgan._data_sampler._discrete_column_category_prob[0][1] == 0.025
+    assert ctgan._data_sampler._discrete_column_category_prob[0][2] == 0.025
 
 
 def test_categorical_nan():
@@ -134,6 +134,33 @@ def test_synthesizer_sample():
     assert isinstance(samples, pd.DataFrame)
 
 
+def test_synthesizer_sampling():
+    """Test the CTGANSynthesizer sampling."""
+    data = pd.DataFrame({
+        'continuous': np.random.random(1000),
+        'discrete': np.repeat(['a', 'b', 'c'], [950, 25, 25])
+    })
+
+    discrete_columns = ['discrete']
+
+    ctgan = CTGANSynthesizer(epochs=100)
+    ctgan.fit(data, discrete_columns)
+
+    samples = ctgan.sample(1000)
+    assert samples['discrete'].value_counts()['a'] > 800
+    assert samples['discrete'].value_counts()['b'] < 100
+    assert samples['discrete'].value_counts()['c'] < 100
+
+    samples = ctgan.sample(1000, condition_column='discrete', condition_value='a')
+    assert samples['discrete'].value_counts()['a'] > 750
+
+    samples = ctgan.sample(1000, condition_column='discrete', condition_value='b')
+    assert samples['discrete'].value_counts()['b'] > 750
+
+    samples = ctgan.sample(1000, condition_column='discrete', condition_value='c')
+    assert samples['discrete'].value_counts()['c'] > 750
+
+
 def test_save_load():
     """Test the CTGANSynthesizer load/save methods."""
     data = pd.DataFrame({