added as_matrix call policy

boost/numpy/matrix.hpp

@@ -52,6 +52,20 @@ public:
 
 };
 
+/**
+ *  @brief CallPolicies that causes a function that returns a numpy.ndarray to
+ *         return a numpy.matrix instead.
+ */
+template <typename Base = python::default_call_policies>
+struct as_matrix : Base {
+    static PyObject * postcall(PyObject *, PyObject * result) {
+        python::object a = python::object(python::handle<>(result));
+        numpy::matrix m(a, false);
+        Py_INCREF(m.ptr());
+        return m.ptr();
+    }
+};
+
 } // namespace boost::numpy
 namespace python
 {

libs/numpy/test/ndarray.py

@@ -16,6 +16,16 @@ class TestNdarray(unittest.TestCase):
                 self.assertEqual(shape,a1.shape)
                 self.assert_((a1 == a2).all())
 
+    def testNdzeros_matrix(self):    
+        for dtp in (numpy.int16, numpy.int32, numpy.float32, numpy.complex128):
+            dt = numpy.dtype(dtp)
+            shape = (6, 10)
+            a1 = ndarray_mod.zeros_matrix(shape, dt)
+            a2 = numpy.matrix(numpy.zeros(shape, dtype=dtp))
+            self.assertEqual(shape,a1.shape)
+            self.assert_((a1 == a2).all())
+            self.assertEqual(type(a1), type(a2))
+
     def testNdarray(self):    
         a = range(0,60)
         for dtp in (numpy.int16, numpy.int32, numpy.float32, numpy.complex128):

libs/numpy/test/ndarray_mod.cpp

@@ -24,10 +24,12 @@ np::ndarray c_empty(p::tuple shape, np::dtype dt)
 np::ndarray transpose(np::ndarray arr) { return arr.transpose();}
 np::ndarray squeeze(np::ndarray arr) { return arr.squeeze();}
 np::ndarray reshape(np::ndarray arr,p::tuple tup) { return arr.reshape(tup);}
+
 BOOST_PYTHON_MODULE(ndarray_mod) 
 {
   np::initialize();
   p::def("zeros", zeros);
+  p::def("zeros_matrix", zeros, np::as_matrix<>());
   p::def("array", array2);
   p::def("array", array1);
   p::def("empty", empty1);