Provide an ExNode::_sympy_ method so that sympy functions can accept ExNode (they already accepted Ex).

Author: Kasper Peeters

core/pythoncdb/py_ex.cc

@@ -290,7 +290,6 @@ namespace cadabra {
 		return str.str();
 		}
 
-
 	pybind11::object Ex_as_sympy(Ex_ptr ex)
 		{
 		// Generate a string which can be parsed by Sympy.
@@ -306,6 +305,11 @@ namespace cadabra {
 		return ret;
 		}
 
+	pybind11::object ExNode_as_sympy(const ExNode& exnode)
+		{
+		return Ex_as_sympy(exnode.ex);
+		}
+
 	std::string Ex_as_sympy_string(Ex_ptr ex)
 		{
 		// Check to see if the expression is a scalar without dummy indices.
@@ -692,6 +696,7 @@ namespace cadabra {
 			.def("__setitem__", &ExNode::setitem_iterator)
 			.def("_latex_", &ExNode::_latex_)
 			.def("__str__", &ExNode::__str__)
+			.def("_sympy_", &ExNode_as_sympy)
 			.def("terms", &ExNode::terms, "Return an ExNode iterator over all terms at the level of the current ExNode.")
 			.def("factors", &ExNode::factors, "Return an ExNode iterator over all factors at the level of the current ExNode.")
 			.def("own_indices", &ExNode::own_indices, "Return an ExNode iterator over all indices which are not inherited from child nodes.")

tests/sympy_cdb.cdb

@@ -4,7 +4,7 @@ def test01():
    __cdbkernel__=create_scope()    
    ex:=3x + x**2 + a x**2 + b x;
    q=SympyBridge(ex)
-   q.from_sympy( str(sympy.collect(q.to_sympy(), str($x$))) )
+   q.from_sympy( str(sympy.collect(q.to_sympy(), $x$)) )
    tst:= x**2 (a + 1) + x ( b + 3) - @(ex);
    assert(tst==0)
    print("Test 01 passed")