Add test for trace.

theano/sandbox/linalg/tests/test_linalg.py

@@ -25,7 +25,7 @@ from theano.sandbox.linalg.ops import (cholesky,
                                        #alloc_diag,
                                        det,
                                        #PSD_hint,
-                                       #trace,
+                                       trace,
                                        #spectral_radius_bound
                                        )
 
@@ -121,3 +121,23 @@ def test_extract_diag():
         ok = True
     assert ok
 # not testing the view=True case since it is not used anywhere.
+
+def test_trace():
+    rng = numpy.random.RandomState(utt.fetch_seed())
+    x = theano.tensor.matrix()
+    g = trace(x)
+    f = theano.function([x], g)
+
+    m = rng.rand(4, 4).astype(config.floatX)
+    v = numpy.trace(m)
+    assert v == f(m)
+
+    xx = theano.tensor.vector()
+    ok = False
+    try:
+        trace(xx)
+    except TypeError:
+        ok = True
+    assert ok
+
+