feat: added conversion from igraph vectors NumPy array _views_ into the vectors

Author: ntamas

.coveragerc

@@ -1,2 +1,7 @@
 [run]
 omit = src/codegen/*
+
+[report]
+exclude_lines =
+    pragma: no cover
+    if TYPE_CHECKING:

src/igraph_ctypes/_internal/conversion.py

@@ -4,7 +4,7 @@
 
 import numpy as np
 
-from ctypes import memmove, POINTER
+from ctypes import addressof, memmove, POINTER
 from typing import Any, Iterable, Optional, Sequence, TYPE_CHECKING
 
 from .enums import MatrixStorage
@@ -104,8 +104,11 @@
     "igraph_vector_bool_t_to_list",
     "igraph_vector_int_t_to_list",
     "igraph_vector_t_to_numpy_array",
+    "igraph_vector_t_to_numpy_array_view",
     "igraph_vector_bool_t_to_numpy_array",
+    "igraph_vector_bool_t_to_numpy_array_view",
     "igraph_vector_int_t_to_numpy_array",
+    "igraph_vector_int_t_to_numpy_array_view",
     "igraph_vector_int_list_t_to_list_of_numpy_array",
     "igraph_vector_list_t_to_list_of_numpy_array",
     "iterable_edge_indices_to_igraph_vector_int_t",
@@ -700,6 +703,14 @@ def igraph_vector_t_to_numpy_array(vector: _Vector) -> RealArray:
     return result
 
 
+def igraph_vector_t_to_numpy_array_view(vector: _Vector) -> RealArray:
+    n = igraph_vector_size(vector)
+    addr = addressof(igraph_vector_e_ptr(vector, 0).contents)
+    buf_type = igraph_real_t * n
+    buf = buf_type.from_address(addr)
+    return np.frombuffer(buf, dtype=np_type_of_igraph_real_t)
+
+
 def igraph_vector_bool_t_to_numpy_array(vector: _VectorBool) -> BoolArray:
     n = igraph_vector_bool_size(vector)
     result = np.zeros(n, dtype=np_type_of_igraph_bool_t)
@@ -708,6 +719,14 @@ def igraph_vector_bool_t_to_numpy_array(vector: _VectorBool) -> BoolArray:
     return result
 
 
+def igraph_vector_bool_t_to_numpy_array_view(vector: _VectorBool) -> BoolArray:
+    n = igraph_vector_bool_size(vector)
+    addr = addressof(igraph_vector_bool_e_ptr(vector, 0).contents)
+    buf_type = igraph_bool_t * n
+    buf = buf_type.from_address(addr)
+    return np.frombuffer(buf, dtype=np_type_of_igraph_bool_t)
+
+
 def igraph_vector_int_t_to_numpy_array(vector: _VectorInt) -> IntArray:
     n = igraph_vector_int_size(vector)
     result = np.zeros(n, dtype=np_type_of_igraph_integer_t)
@@ -716,6 +735,14 @@ def igraph_vector_int_t_to_numpy_array(vector: _VectorInt) -> IntArray:
     return result
 
 
+def igraph_vector_int_t_to_numpy_array_view(vector: _VectorInt) -> IntArray:
+    n = igraph_vector_int_size(vector)
+    addr = addressof(igraph_vector_int_e_ptr(vector, 0).contents)
+    buf_type = igraph_integer_t * n
+    buf = buf_type.from_address(addr)
+    return np.frombuffer(buf, dtype=np_type_of_igraph_integer_t)
+
+
 def igraph_vector_list_t_to_list_of_numpy_array(
     vector_list: _VectorList,
 ) -> list[RealArray]:

tests/test_conversion.py

@@ -11,10 +11,13 @@
     igraph_matrix_int_t_to_numpy_array,
     igraph_vector_t_to_list,
     igraph_vector_t_to_numpy_array,
+    igraph_vector_t_to_numpy_array_view,
     igraph_vector_bool_t_to_list,
     igraph_vector_bool_t_to_numpy_array,
+    igraph_vector_bool_t_to_numpy_array_view,
     igraph_vector_int_t_to_list,
     igraph_vector_int_t_to_numpy_array,
+    igraph_vector_int_t_to_numpy_array_view,
     igraph_vector_int_list_t_to_list_of_numpy_array,
     igraph_vector_list_t_to_list_of_numpy_array,
     iterable_of_iterable_to_igraph_vector_list_t,
@@ -94,6 +97,22 @@ def test_bool_vector_roundtrip():
     assert (restored_array == expected_array).all()
 
 
+def test_bool_vector_view_roundtrip():
+    input = [False, 0, True, False, "", "yes", True]
+    expected = [bool(x) for x in input]
+    expected_array = array(expected, dtype=bool)
+
+    converted = iterable_to_igraph_vector_bool_t(expected)
+    assert isinstance(converted, _VectorBool)
+
+    restored = igraph_vector_bool_t_to_numpy_array_view(converted)
+    assert (restored == expected_array).all()
+
+    another_restored = igraph_vector_bool_t_to_numpy_array_view(converted)
+    assert (another_restored == expected_array).all()
+    assert restored.data == another_restored.data
+
+
 def test_int_vector_roundtrip():
     input = [1, 4, 7, 11, 8, 3, 5, 6, 2, -6]
     expected = list(input)
@@ -115,6 +134,22 @@ def test_int_vector_roundtrip():
     assert (restored_array == expected_array).all()
 
 
+def test_int_vector_view_roundtrip():
+    input = [1, 4, 7, 11, 8, 3, 5, 6, 2, -6]
+    expected = list(input)
+    expected_array = array(expected)
+
+    converted = iterable_to_igraph_vector_int_t(expected)
+    assert isinstance(converted, _VectorInt)
+
+    restored = igraph_vector_int_t_to_numpy_array_view(converted)
+    assert (restored == expected_array).all()
+
+    another_restored = igraph_vector_int_t_to_numpy_array_view(converted)
+    assert (another_restored == expected_array).all()
+    assert restored.data == another_restored.data
+
+
 def test_real_vector_roundtrip():
     input = [1.23, 4.567, 8.91011, -12.3456]
     expected = list(input)
@@ -136,6 +171,22 @@ def test_real_vector_roundtrip():
     assert (restored_array == expected_array).all()
 
 
+def test_real_vector_view_roundtrip():
+    input = [1.23, 4.567, 8.91011, -12.3456]
+    expected = list(input)
+    expected_array = array(expected)
+
+    converted = iterable_to_igraph_vector_t(expected)
+    assert isinstance(converted, _Vector)
+
+    restored = igraph_vector_t_to_numpy_array_view(converted)
+    assert (restored == expected_array).all()
+
+    another_restored = igraph_vector_t_to_numpy_array_view(converted)
+    assert (another_restored == expected_array).all()
+    assert restored.data == another_restored.data
+
+
 def test_int_matrix_roundtrip():
     input = [
         [0, 1, 2, 3, 4],
@@ -196,7 +247,7 @@ def test_int_vector_list_roundtrip():
     restored_items = igraph_vector_int_list_t_to_list_of_numpy_array(converted)
     assert len(restored_items) == len(input)
 
-    for original_item, restored_item in zip(input, restored_items):
+    for original_item, restored_item in zip(input, restored_items, strict=True):
         assert (array(original_item) == restored_item).all()
 
 
@@ -214,12 +265,12 @@ def test_vector_list_roundtrip():
     restored_items = igraph_vector_list_t_to_list_of_numpy_array(converted)
     assert len(restored_items) == len(input)
 
-    for original_item, restored_item in zip(input, restored_items):
+    for original_item, restored_item in zip(input, restored_items, strict=True):
         assert (array(original_item) == restored_item).all()
 
 
 def test_vertex_selector():
-    g = create_empty_graph(5)._instance
+    g = create_empty_graph(5)
 
     vs = vertex_selector_to_igraph_vs_t(None, g)
     assert vs.unwrap().type == VertexSequenceType.NONE
@@ -246,7 +297,6 @@ def test_vertex_selector():
 def test_edge_selector():
     g = create_empty_graph(5)
     g.add_edges([(0, 1), (1, 2), (2, 4), (4, 0)])
-    g = g._instance
 
     es = edge_selector_to_igraph_es_t(None, g)
     assert es.unwrap().type == EdgeSequenceType.NONE