Merge pull request #2124 from abergeron/fix_scan_leak

theano/scan_module/numpy_api_changes.diff

+diff --git a/theano/scan_module/scan_perform.c b/theano/scan_module/scan_perform.c
+index aaebb43..2d06b29 100644
+--- a/theano/scan_module/scan_perform.c
++++ b/theano/scan_module/scan_perform.c
+@@ -5595,7 +5595,7 @@ static int __pyx_pf_5numpy_7ndarray___getbuffer__(PyArrayObject *__pyx_v_self, P
+  *             cdef list stack
+  *             cdef int offset
+  */
+-  __pyx_t_4 = ((PyObject *)__pyx_v_self->descr);
++  __pyx_t_4 = ((PyObject *)PyArray_DESCR(__pyx_v_self));
+   __Pyx_INCREF(__pyx_t_4);
+   __pyx_v_descr = ((PyArray_Descr *)__pyx_t_4);
+   __pyx_t_4 = 0;
+@@ -7147,7 +7147,7 @@ static CYTHON_INLINE void __pyx_f_5numpy_set_array_base(PyArrayObject *__pyx_v_a
+  *      arr.base = baseptr
+  * 
+  */
+-  Py_XDECREF(__pyx_v_arr->base);
++  Py_XDECREF(PyArray_BASE(__pyx_v_arr));
+ 
+   /* "/home/anakha/.local/lib/python2.7/site-packages/Cython/Includes/numpy/__init__.pxd":974
+  *          baseptr = <PyObject*>base
+@@ -7156,7 +7156,11 @@ static CYTHON_INLINE void __pyx_f_5numpy_set_array_base(PyArrayObject *__pyx_v_a
+  * 
+  * cdef inline object get_array_base(ndarray arr):
+  */
+-  __pyx_v_arr->base = __pyx_v_baseptr;
++#if NPY_API < 0x00000007
++  PyArray_BASE(__pyx_v_arr) = __pyx_v_baseptr;
++#else
++  PyArray_SetBaseObject(__pyx_v_arr, __pyx_v_baseptr);
++#endif
+ 
+   /* "/home/anakha/.local/lib/python2.7/site-packages/Cython/Includes/numpy/__init__.pxd":966
+  * 
+@@ -7191,7 +7195,7 @@ static CYTHON_INLINE PyObject *__pyx_f_5numpy_get_array_base(PyArrayObject *__py
+  *         return None
+  *     else:
+  */
+-  __pyx_t_1 = ((__pyx_v_arr->base == NULL) != 0);
++  __pyx_t_1 = ((PyArray_BASE(__pyx_v_arr) == NULL) != 0);
+   if (__pyx_t_1) {
+ 
+     /* "/home/anakha/.local/lib/python2.7/site-packages/Cython/Includes/numpy/__init__.pxd":978
+@@ -7214,8 +7218,8 @@ static CYTHON_INLINE PyObject *__pyx_f_5numpy_get_array_base(PyArrayObject *__py
+  *         return <object>arr.base             # <<<<<<<<<<<<<<
+  */
+     __Pyx_XDECREF(__pyx_r);
+-    __Pyx_INCREF(((PyObject *)__pyx_v_arr->base));
+-    __pyx_r = ((PyObject *)__pyx_v_arr->base);
++    __Pyx_INCREF(((PyObject *)PyArray_BASE(__pyx_v_arr)));
++    __pyx_r = ((PyObject *)PyArray_BASE(__pyx_v_arr));
+     goto __pyx_L0;
+   }
+ 

theano/scan_module/scan_op.py

@@ -1104,6 +1104,13 @@ class Scan(PureOp):
                     # little trick that I used
                     outs[idx][0] = outs[idx][0][:-(n_steps - i)]
 
+        # We never reuse the input or output storage of the
+        # inner function so we clear it.
+        for i_s in input_storage:
+            i_s.storage[0] = None
+        for o_s in output_storage:
+            o_s.storage[0] = None
+
         t_call = time.time() - t0_call
         # NOTE: make this match what's in function_module.Function
         # and this little string helps us to find this spot:

theano/scan_module/scan_perform.pyx

@@ -62,7 +62,7 @@ import copy
 
 
 def get_version():
-    return 0.281
+    return 0.283
 
 @cython.boundscheck(False)
 def perform(
@@ -456,6 +456,13 @@ def perform(
                 sh0 = outs[idx][0].shape[0]
                 outs[idx][0] = outs[idx][0][:sh0-(n_steps - i)]
 
+    # We never reuse the input or output storage of the
+    # inner function so we clear it.
+    for i_s in input_storage:
+        i_s.storage[0] = None
+    for o_s in output_storage:
+        o_s.storage[0] = None
+
     t_call = time.time() - t0_call
 
     if hasattr(fnct.maker, 'profile'):

theano/scan_module/scan_perform_ext.py

@@ -16,7 +16,7 @@ _logger = logging.getLogger('theano.scan_module.scan_perform')
 _logger.setLevel(logging.WARN)
 
 
-version = 0.281  # must match constant returned in function get_version()
+version = 0.283  # must match constant returned in function get_version()
 
 need_reload = False
 

theano/scan_module/tests/test_scan.py

@@ -18,6 +18,7 @@ from theano.compile.pfunc import rebuild_collect_shared
 from theano.gof.python25 import any
 from theano.tests import unittest_tools as utt
 import theano.scalar.sharedvar
+from theano.scan_module.scan_op import Scan
 from theano.gof.python25 import OrderedDict
 from theano.compat import PY3
 
@@ -261,6 +262,45 @@ class T_Scan(unittest.TestCase):
         theano_values = my_f(state, steps)
         utt.assert_allclose(numpy_values, theano_values)
 
+    # Test that the inner input_storage and output_storage are
+    # properly cleared
+    def test_inner_storage_leak(self):
+        def f_pow2(x_tm1):
+            return 2 * x_tm1
+
+        state = theano.tensor.scalar('state')
+        n_steps = theano.tensor.iscalar('nsteps')
+        output, updates = theano.scan(f_pow2,
+                                      [],
+                                      state,
+                                      [],
+                                      n_steps=n_steps)
+
+        f = theano.function([state, n_steps],
+                            output,
+                            updates=updates,
+                            allow_input_downcast=True)
+
+        scan_node = [node for node in f.maker.fgraph.toposort()
+                     if isinstance(node.op, Scan)]
+
+        assert len(scan_node) == 1
+        scan_node = scan_node[0]
+
+        # Make sure they start out as None
+        assert all(i.value is None for i in scan_node.op.fn.input_storage)
+        assert all(o.value is None for o in scan_node.op.fn.output_storage)
+
+        rng = numpy.random.RandomState(utt.fetch_seed())
+        state = rng.uniform()
+        steps = 5
+
+        f(state, steps)
+
+        # And that they stay that way
+        assert all(i.value is None for i in scan_node.op.fn.input_storage)
+        assert all(o.value is None for o in scan_node.op.fn.output_storage)
+
     # generator network, only one output , type scalar ; no sequence or
     # non sequence arguments
     def test_generator_one_output_scalar(self):