[MXNET-160] Fix for issue 9062 (apache#10413)

* fix typo in sample_multinomial_op.h (issue apache#9062) * add test case for 1D prob input case
zheng-da · Jun 28, 2018 · a406b54 · a406b54
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Showing 2 changed files with 30 additions and 25 deletions.
diff --git a/src/operator/random/sample_multinomial_op.h b/src/operator/random/sample_multinomial_op.h
@@ -70,10 +70,10 @@ inline bool SampleMultinomialOpShape(const nnvm::NodeAttrs& attrs,
   if (ishape.ndim() == 1) {
     if (param.shape.ndim()) {
       SHAPE_ASSIGN_CHECK(*out_attrs, 0, param.shape);
-      if (param.get_prob) SHAPE_ASSIGN_CHECK(*out_attrs, 0, param.shape);
+      if (param.get_prob) SHAPE_ASSIGN_CHECK(*out_attrs, 1, param.shape);
     } else {
       SHAPE_ASSIGN_CHECK(*out_attrs, 0, TShape(1));
-      if (param.get_prob) SHAPE_ASSIGN_CHECK(*out_attrs, 0, TShape(1));
+      if (param.get_prob) SHAPE_ASSIGN_CHECK(*out_attrs, 1, TShape(1));
     }
     return true;
   }

diff --git a/tests/python/unittest/test_random.py b/tests/python/unittest/test_random.py
@@ -276,29 +276,34 @@ def test_parallel_random_seed_setting():
 
 @with_seed()
 def test_sample_multinomial():
-    x = mx.nd.array([[0,1,2,3,4],[4,3,2,1,0]])/10.0
-    dx = mx.nd.ones_like(x)
-    mx.contrib.autograd.mark_variables([x], [dx])
-    # Adding rtol and increasing samples needed to pass with seed 2951820647
-    samples = 5000
-    with mx.autograd.record():
-        y, prob = mx.nd.random.multinomial(x, shape=samples, get_prob=True)
-        r = prob * 5
-        r.backward()
-
-    y = y.asnumpy()
-    x = x.asnumpy()
-    for i in range(x.shape[0]):
-
-        freq = np.bincount(y[i], minlength=5)/np.float32(samples)*x[i].sum()
-        mx.test_utils.assert_almost_equal(freq, x[i], rtol=0.20)
-        rprob = x[i][y[i]]/x[i].sum()
-        mx.test_utils.assert_almost_equal(np.log(rprob), prob.asnumpy()[i])
-
-        real_dx = np.zeros((5,))
-        for j in range(samples):
-            real_dx[y[i][j]] += 5.0 / rprob[j]
-        mx.test_utils.assert_almost_equal(real_dx, dx.asnumpy()[i], rtol=1e-4)
+    for x in [mx.nd.array([[0,1,2,3,4],[4,3,2,1,0]])/10.0, mx.nd.array([0,1,2,3,4])/10.0]:
+        dx = mx.nd.ones_like(x)
+        mx.contrib.autograd.mark_variables([x], [dx])
+        # Adding rtol and increasing samples needed to pass with seed 2951820647
+        samples = 5000
+        with mx.autograd.record():
+            y, prob = mx.nd.random.multinomial(x, shape=samples, get_prob=True)
+            r = prob * 5
+            r.backward()
+
+        y = y.asnumpy()
+        x = x.asnumpy()
+        dx = dx.asnumpy()
+        if len(x.shape) is 1:
+            x = x.reshape((1, x.shape[0]))
+            dx = dx.reshape(1, dx.shape[0])
+            y = y.reshape((1, y.shape[0]))
+            prob = prob.reshape((1, prob.shape[0]))
+        for i in range(x.shape[0]):
+            freq = np.bincount(y[i,:], minlength=5)/np.float32(samples)*x[i,:].sum()
+            mx.test_utils.assert_almost_equal(freq, x[i], rtol=0.20)
+            rprob = x[i][y[i]]/x[i].sum()
+            mx.test_utils.assert_almost_equal(np.log(rprob), prob.asnumpy()[i], atol=1e-5)
+
+            real_dx = np.zeros((5,))
+            for j in range(samples):
+                real_dx[y[i][j]] += 5.0 / rprob[j]
+            mx.test_utils.assert_almost_equal(real_dx, dx[i, :], rtol=1e-4, atol=1e-5)
 
 # Test the generators with the chi-square testing
 @with_seed()