Merge pull request #3035 from thomasmesnard/Inrangegrad

theano/scalar/tests/test_basic.py

@@ -21,7 +21,7 @@ from theano.scalar.basic import (floats, float32, float64,
                                  ints, int8, int32, complex64,
                                  ComplexError, IntDiv, TrueDiv,
                                  Composite, add, div_proxy,
-                                 and_, eq, neq, invert, mul, Scalar)
+                                 and_, eq, neq, invert, mul, Scalar, InRange)
 from theano.scalar.basic import (
     true_div, inv, log, log2, log10, log1p, exp, exp2, expm1, sqrt, deg2rad,
     rad2deg, cos, arccos, sin, arcsin, tan, arctan, arctan2, cosh, arccosh,
@@ -413,6 +413,32 @@ def test_grad_identity():
     theano.gradient.grad(l, x)
 
 
+def test_grad_inrange():
+    for bound_definition in [(True, True), (False, False)]:
+        # Instantiate op, and then take the gradient
+        op = InRange(*bound_definition)
+        x = theano.tensor.fscalar('x')
+        low = theano.tensor.fscalar('low')
+        high = theano.tensor.fscalar('high')
+        out = op(x, low, high)
+        gx, glow, ghigh = theano.tensor.grad(out, [x, low, high])
+
+        # We look if the gradient are equal to zero
+        # if x is lower than the lower bound,
+        # equal to the lower bound, between lower and higher bound,
+        # equal to the higher bound and higher than the higher
+        # bound.
+        # Mathematically we should have an infinite gradient when
+        # x is equal to the lower or higher bound but in that case
+        # Theano defines the gradient to be zero for stability.
+        f = theano.function([x, low, high], [gx, glow, ghigh])
+        utt.assert_allclose(f(0, 1, 5), [0, 0, 0])
+        utt.assert_allclose(f(1, 1, 5), [0, 0, 0])
+        utt.assert_allclose(f(2, 1, 5), [0, 0, 0])
+        utt.assert_allclose(f(5, 1, 5), [0, 0, 0])
+        utt.assert_allclose(f(7, 1, 5), [0, 0, 0])
+
+
 # Testing of Composite is done in tensor/tests/test_opt.py
 # in test_fusion, TestCompositeCodegen