preliminary design of buffer protocol stuff

shogun-toolbox · Jul 13, 2012 · a184880 · a184880
1 parent fdd7763
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diff --git a/examples/undocumented/python_modular/features_dense_buffer_modular.py b/examples/undocumented/python_modular/features_dense_buffer_modular.py
@@ -0,0 +1,29 @@
+from shogun.Features import RealFeatures
+from numpy import array, float64, all
+
+# create dense matrices A,B,C
+matrix=array([[1,2,3],[4,0,0],[0,0,0],[0,5,0],[0,0,6],[9,9,9]], dtype=float64)
+
+parameter_list = [[matrix]]
+
+# ... of type LongInt
+def features_dense_real_modular(A=matrix):
+
+# ... of type Real, LongInt and Byte
+	a=RealFeatures(A)
+	a.set_feature_vector(array([1,4,0,0,0,9], dtype=float64), 0)
+
+# get matrix
+	a_out = a.get_feature_matrix()
+
+	b = array(a) + a
+
+	print b
+	print a_out
+
+	assert(all(a_out==A))
+	return a_out
+
+if __name__=='__main__':
+	print('dense_real')
+	features_dense_real_modular(*parameter_list[0])
diff --git a/src/interfaces/modular/Features.i b/src/interfaces/modular/Features.i
@@ -284,6 +284,77 @@ namespace shogun
 #endif
 }
 
+/* Buffer protocol stuff for DenseFeatures */
+%define BUFFER_DENSEFEATURES(name, type_name, type)
+
+%wrapper 
+%{
+	static int name ## _getbuffer(PyObject *exporter, Py_buffer *view, int flags)
+	{
+		CDenseFeatures< type > * self = 0;
+		void *argp1 = 0 ;
+		int res1 = 0 ;
+
+		int num_feat = 0, num_vec = 0;
+
+		Py_ssize_t* shape;
+		Py_ssize_t* stride;
+
+		// TODO validate argp1
+		res1 = SWIG_ConvertPtr(exporter, &argp1, SWIGTYPE_p_shogun__CDenseFeaturesT_ ## type ## _t, 0 |  0 );
+		self = reinterpret_cast< CDenseFeatures < type > * >(argp1);
+
+		view->buf = self->get_feature_matrix(num_feat, num_vec);
+
+		shape = new Py_ssize_t[2];
+		shape[0]=num_feat;
+		shape[1]=num_vec;
+
+		stride = new Py_ssize_t[2];
+		stride[0]=sizeof( type );
+		stride[1]=sizeof( type ) * num_feat;
+
+		view->len = shape[0]*stride[0];
+		view->itemsize = stride[0];
+		view->readonly=0;
+
+		// TODO add formats for more types
+		view->format="d\0";
+
+		view->ndim = 2;
+		view->shape = shape;
+		view->strides = stride;
+		view->suboffsets = NULL;
+		view->internal = NULL;
+
+		view->obj=(PyObject*) exporter;
+		Py_INCREF(exporter);
+
+		return 0;
+	}
+
+	static void name ## _releasebuffer(PyObject *exporter, Py_buffer *view)
+	{
+		if(view->shape != NULL)
+			delete[] view->shape;
+
+		if(view->strides != NULL)
+			delete[] view->strides;
+	}
+
+	static long name ## _flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_NEWBUFFER | Py_TPFLAGS_BASETYPE;
+%}
+
+%init
+%{
+	SwigPyBuiltin__shogun__CDenseFeaturesT_ ## type_name ## _t_type.ht_type.tp_flags = name ## _flags;
+%}
+
+%feature("python:bf_getbuffer") CDenseFeatures< type_name > #name "_getbuffer"
+%feature("python:bf_releasebuffer") CDenseFeatures< type_name > #name "_releasebuffer"
+
+%enddef
+
 /* Templated Class DenseFeatures */
 %include <shogun/features/DenseFeatures.h>
 namespace shogun
@@ -322,6 +393,7 @@ namespace shogun
     %template(ShortRealFeatures) CDenseFeatures<float32_t>;
 #endif
 #ifdef USE_FLOAT64
+	BUFFER_DENSEFEATURES(RealFeatures, float64_t, double)
     %template(RealFeatures) CDenseFeatures<float64_t>;
 #endif
 }