array: implement array resize
diff --git a/include/pybind11/numpy.h b/include/pybind11/numpy.h
index 44ea427..ba9402b 100644
--- a/include/pybind11/numpy.h
+++ b/include/pybind11/numpy.h
@@ -129,6 +129,11 @@
NPY_STRING_, NPY_UNICODE_, NPY_VOID_
};
+ typedef struct {
+ Py_intptr_t *ptr;
+ int len;
+ } PyArray_Dims;
+
static npy_api& get() {
static npy_api api = lookup();
return api;
@@ -159,6 +164,7 @@
Py_ssize_t *, PyObject **, PyObject *);
PyObject *(*PyArray_Squeeze_)(PyObject *);
int (*PyArray_SetBaseObject_)(PyObject *, PyObject *);
+ PyObject* (*PyArray_Resize_)(PyObject*, PyArray_Dims*, int, int);
private:
enum functions {
API_PyArray_GetNDArrayCFeatureVersion = 211,
@@ -168,6 +174,7 @@
API_PyArray_DescrFromType = 45,
API_PyArray_DescrFromScalar = 57,
API_PyArray_FromAny = 69,
+ API_PyArray_Resize = 80,
API_PyArray_NewCopy = 85,
API_PyArray_NewFromDescr = 94,
API_PyArray_DescrNewFromType = 9,
@@ -197,6 +204,7 @@
DECL_NPY_API(PyArray_DescrFromType);
DECL_NPY_API(PyArray_DescrFromScalar);
DECL_NPY_API(PyArray_FromAny);
+ DECL_NPY_API(PyArray_Resize);
DECL_NPY_API(PyArray_NewCopy);
DECL_NPY_API(PyArray_NewFromDescr);
DECL_NPY_API(PyArray_DescrNewFromType);
@@ -652,6 +660,21 @@
return reinterpret_steal<array>(api.PyArray_Squeeze_(m_ptr));
}
+ /// Resize array to given shape
+ /// If refcheck is true and more that one reference exist to this array
+ /// then resize will succeed only if it makes a reshape, i.e. original size doesn't change
+ void resize(ShapeContainer new_shape, bool refcheck = true) {
+ detail::npy_api::PyArray_Dims d = {
+ new_shape->data(), int(new_shape->size())
+ };
+ // try to resize, set ordering param to -1 cause it's not used anyway
+ object new_array = reinterpret_steal<object>(
+ detail::npy_api::get().PyArray_Resize_(m_ptr, &d, int(refcheck), -1)
+ );
+ if (!new_array) throw error_already_set();
+ if (isinstance<array>(new_array)) { *this = std::move(new_array); }
+ }
+
/// Ensure that the argument is a NumPy array
/// In case of an error, nullptr is returned and the Python error is cleared.
static array ensure(handle h, int ExtraFlags = 0) {
diff --git a/tests/test_numpy_array.cpp b/tests/test_numpy_array.cpp
index 269f18b..85c185f 100644
--- a/tests/test_numpy_array.cpp
+++ b/tests/test_numpy_array.cpp
@@ -273,4 +273,25 @@
sm.def("array_initializer_list", []() { return py::array_t<float>({ 1, 2 }); });
sm.def("array_initializer_list", []() { return py::array_t<float>({ 1, 2, 3 }); });
sm.def("array_initializer_list", []() { return py::array_t<float>({ 1, 2, 3, 4 }); });
-});
+
+ // reshape array to 2D without changing size
+ sm.def("array_reshape2", [](py::array_t<double> a) {
+ const size_t dim_sz = (size_t)std::sqrt(a.size());
+ if (dim_sz * dim_sz != a.size())
+ throw std::domain_error("array_reshape2: input array total size is not a squared integer");
+ a.resize({dim_sz, dim_sz});
+ });
+
+ // resize to 3D array with each dimension = N
+ sm.def("array_resize3", [](py::array_t<double> a, size_t N, bool refcheck) {
+ a.resize({N, N, N}, refcheck);
+ });
+
+ // return 2D array with Nrows = Ncols = N
+ sm.def("create_and_resize", [](size_t N) {
+ py::array_t<double> a;
+ a.resize({N, N});
+ std::fill(a.mutable_data(), a.mutable_data() + a.size(), 42.);
+ return a;
+ });
+});
\ No newline at end of file
diff --git a/tests/test_numpy_array.py b/tests/test_numpy_array.py
index 6281fa4..10af748 100644
--- a/tests/test_numpy_array.py
+++ b/tests/test_numpy_array.py
@@ -389,3 +389,38 @@
with pytest.raises(ValueError) as excinfo:
array_t_fail_test()
assert str(excinfo.value) == 'cannot create a pybind11::array_t from a nullptr'
+
+
+def test_array_resize(msg):
+ from pybind11_tests.array import (array_reshape2, array_resize3)
+
+ a = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9], dtype='float64')
+ array_reshape2(a)
+ assert(a.size == 9)
+ assert(np.all(a == [[1, 2, 3], [4, 5, 6], [7, 8, 9]]))
+
+ # total size change should succced with refcheck off
+ array_resize3(a, 4, False)
+ assert(a.size == 64)
+ # ... and fail with refcheck on
+ try:
+ array_resize3(a, 3, True)
+ except ValueError as e:
+ assert(str(e).startswith("cannot resize an array"))
+ # transposed array doesn't own data
+ b = a.transpose()
+ try:
+ array_resize3(b, 3, False)
+ except ValueError as e:
+ assert(str(e).startswith("cannot resize this array: it does not own its data"))
+ # ... but reshape should be fine
+ array_reshape2(b)
+ assert(b.shape == (8, 8))
+
+
+@pytest.unsupported_on_pypy
+def test_array_create_and_resize(msg):
+ from pybind11_tests.array import create_and_resize
+ a = create_and_resize(2)
+ assert(a.size == 4)
+ assert(np.all(a == 42.))