Fix Eigen argument doc strings

include/pybind11/eigen.h

@@ -179,20 +179,21 @@ template <typename Type_> struct EigenProps {
         constexpr bool show_c_contiguous = show_order && requires_row_major;
         constexpr bool show_f_contiguous = !show_c_contiguous && show_order && requires_col_major;
 
-    return _("numpy.ndarray[") + npy_format_descriptor<Scalar>::name() +
-        _("[")  + _<fixed_rows>(_<(size_t) rows>(), _("m")) +
-        _(", ") + _<fixed_cols>(_<(size_t) cols>(), _("n")) +
-        _("]") +
-        // For a reference type (e.g. Ref<MatrixXd>) we have other constraints that might need to be
-        // satisfied: writeable=True (for a mutable reference), and, depending on the map's stride
-        // options, possibly f_contiguous or c_contiguous.  We include them in the descriptor output
-        // to provide some hint as to why a TypeError is occurring (otherwise it can be confusing to
-        // see that a function accepts a 'numpy.ndarray[float64[3,2]]' and an error message that you
-        // *gave* a numpy.ndarray of the right type and dimensions.
-        _<show_writeable>(", flags.writeable", "") +
-        _<show_c_contiguous>(", flags.c_contiguous", "") +
-        _<show_f_contiguous>(", flags.f_contiguous", "") +
-        _("]");
+        return type_descr(_("numpy.ndarray[") + npy_format_descriptor<Scalar>::name() +
+            _("[")  + _<fixed_rows>(_<(size_t) rows>(), _("m")) +
+            _(", ") + _<fixed_cols>(_<(size_t) cols>(), _("n")) +
+            _("]") +
+            // For a reference type (e.g. Ref<MatrixXd>) we have other constraints that might need to be
+            // satisfied: writeable=True (for a mutable reference), and, depending on the map's stride
+            // options, possibly f_contiguous or c_contiguous.  We include them in the descriptor output
+            // to provide some hint as to why a TypeError is occurring (otherwise it can be confusing to
+            // see that a function accepts a 'numpy.ndarray[float64[3,2]]' and an error message that you
+            // *gave* a numpy.ndarray of the right type and dimensions.
+            _<show_writeable>(", flags.writeable", "") +
+            _<show_c_contiguous>(", flags.c_contiguous", "") +
+            _<show_f_contiguous>(", flags.f_contiguous", "") +
+            _("]")
+        );
     }
 };
 
@@ -318,7 +319,7 @@ struct type_caster<Type, enable_if_t<is_eigen_dense_plain<Type>::value>> {
         return cast_impl(src, policy, parent);
     }
 
-    static PYBIND11_DESCR name() { return type_descr(props::descriptor()); }
+    static PYBIND11_DESCR name() { return props::descriptor(); }
 
     operator Type*() { return &value; }
     operator Type&() { return value; }

tests/test_eigen.cpp

@@ -287,6 +287,13 @@ test_initializer eigen([](py::module &m) {
     m.def("iss738_f1", &adjust_matrix<const Eigen::Ref<const Eigen::MatrixXd> &>, py::arg().noconvert());
     m.def("iss738_f2", &adjust_matrix<const Eigen::Ref<const Eigen::Matrix<double, -1, -1, Eigen::RowMajor>> &>, py::arg().noconvert());
 
+    // Make sure named arguments are working properly:
+    m.def("matrix_multiply", [](const py::EigenDRef<const Eigen::MatrixXd> A, const py::EigenDRef<const Eigen::MatrixXd> B)
+            -> Eigen::MatrixXd {
+        if (A.cols() != B.rows()) throw std::domain_error("Nonconformable matrices!");
+        return A * B;
+    }, py::arg("A"), py::arg("B"));
+
     py::class_<CustomOperatorNew>(m, "CustomOperatorNew")
         .def(py::init<>())
         .def_readonly("a", &CustomOperatorNew::a)

tests/test_eigen.py

@@ -75,15 +75,15 @@ def test_mutator_descriptors():
     fixed_mutator_a(zc)
     with pytest.raises(TypeError) as excinfo:
         fixed_mutator_r(zc)
-    assert ('(numpy.ndarray[float32[5, 6], flags.writeable, flags.c_contiguous]) -> arg0: None'
+    assert ('(arg0: numpy.ndarray[float32[5, 6], flags.writeable, flags.c_contiguous]) -> None'
             in str(excinfo.value))
     with pytest.raises(TypeError) as excinfo:
         fixed_mutator_c(zr)
-    assert ('(numpy.ndarray[float32[5, 6], flags.writeable, flags.f_contiguous]) -> arg0: None'
+    assert ('(arg0: numpy.ndarray[float32[5, 6], flags.writeable, flags.f_contiguous]) -> None'
             in str(excinfo.value))
     with pytest.raises(TypeError) as excinfo:
         fixed_mutator_a(np.array([[1, 2], [3, 4]], dtype='float32'))
-    assert ('(numpy.ndarray[float32[5, 6], flags.writeable]) -> arg0: None'
+    assert ('(arg0: numpy.ndarray[float32[5, 6], flags.writeable]) -> None'
             in str(excinfo.value))
     zr.flags.writeable = False
     with pytest.raises(TypeError):
@@ -582,6 +582,29 @@ def test_dense_signature(doc):
     """
 
 
+def test_named_arguments():
+    from pybind11_tests import matrix_multiply
+
+    a = np.array([[1.0, 2], [3, 4], [5, 6]])
+    b = np.ones((2, 1))
+
+    assert np.all(matrix_multiply(a, b) == np.array([[3.], [7], [11]]))
+    assert np.all(matrix_multiply(A=a, B=b) == np.array([[3.], [7], [11]]))
+    assert np.all(matrix_multiply(B=b, A=a) == np.array([[3.], [7], [11]]))
+
+    with pytest.raises(ValueError) as excinfo:
+        matrix_multiply(b, a)
+    assert str(excinfo.value) == 'Nonconformable matrices!'
+
+    with pytest.raises(ValueError) as excinfo:
+        matrix_multiply(A=b, B=a)
+    assert str(excinfo.value) == 'Nonconformable matrices!'
+
+    with pytest.raises(ValueError) as excinfo:
+        matrix_multiply(B=a, A=b)
+    assert str(excinfo.value) == 'Nonconformable matrices!'
+
+
 @pytest.requires_eigen_and_scipy
 def test_sparse():
     from pybind11_tests import sparse_r, sparse_c, sparse_copy_r, sparse_copy_c