From c053d00b4cf1fde35364e539d823d708ee0aec0a Mon Sep 17 00:00:00 2001
From: Khizar1 <11738208+Khizar1@users.noreply.github.com>
Date: Sun, 12 Oct 2025 15:58:16 +0000
Subject: [PATCH 1/3] Handle non c-contagious numpy arrays efficiently in
 py_array_to_vectors_*

---
 cpp/pybind/utility/eigen.cpp | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/cpp/pybind/utility/eigen.cpp b/cpp/pybind/utility/eigen.cpp
index dd480d2cd78..b8e5981717b 100644
--- a/cpp/pybind/utility/eigen.cpp
+++ b/cpp/pybind/utility/eigen.cpp
@@ -36,7 +36,12 @@ py::class_<Vector, holder_type> bind_vector_without_repr(
 //   bindings for each py array types.
 template <typename EigenVector>
 std::vector<EigenVector> py_array_to_vectors_double(
-        py::array_t<double, py::array::c_style | py::array::forcecast> array) {
+        py::array_t<double> array) {  // remove the restrictive flags here
+    // Ensure array is contiguous (C-style)
+    if (!(array.flags() & (py::array::c_style))) {
+        // Make a contiguous copy if necessary
+        array = py::array_t<double, py::array::c_style>(array);
+    }
     int64_t eigen_vector_size = EigenVector::SizeAtCompileTime;
     if (array.ndim() != 2 || array.shape(1) != eigen_vector_size) {
         throw py::cast_error();
@@ -54,7 +59,10 @@ std::vector<EigenVector> py_array_to_vectors_double(
 
 template <typename EigenVector>
 std::vector<EigenVector> py_array_to_vectors_int(
-        py::array_t<int, py::array::c_style | py::array::forcecast> array) {
+        py::array_t<int> array) {
+    if (!(array.flags() & (py::array::c_style))) {
+        array = py::array_t<int, py::array::c_style>(array);
+    }
     int64_t eigen_vector_size = EigenVector::SizeAtCompileTime;
     if (array.ndim() != 2 || array.shape(1) != eigen_vector_size) {
         throw py::cast_error();
@@ -71,7 +79,10 @@ template <typename EigenVector,
           typename EigenAllocator = Eigen::aligned_allocator<EigenVector>>
 std::vector<EigenVector, EigenAllocator>
 py_array_to_vectors_int_eigen_allocator(
-        py::array_t<int, py::array::c_style | py::array::forcecast> array) {
+        py::array_t<int> array) {
+    if (!(array.flags() & (py::array::c_style))) {
+        array = py::array_t<int, py::array::c_style>(array);
+    }
     int64_t eigen_vector_size = EigenVector::SizeAtCompileTime;
     if (array.ndim() != 2 || array.shape(1) != eigen_vector_size) {
         throw py::cast_error();
@@ -88,7 +99,10 @@ template <typename EigenVector,
           typename EigenAllocator = Eigen::aligned_allocator<EigenVector>>
 std::vector<EigenVector, EigenAllocator>
 py_array_to_vectors_int64_eigen_allocator(
-        py::array_t<int64_t, py::array::c_style | py::array::forcecast> array) {
+        py::array_t<int64_t> array) {
+    if (!(array.flags() & (py::array::c_style))) {
+        array = py::array_t<int64_t, py::array::c_style>(array);
+    }
     int64_t eigen_vector_size = EigenVector::SizeAtCompileTime;
     if (array.ndim() != 2 || array.shape(1) != eigen_vector_size) {
         throw py::cast_error();

From 31b2ba65a17c1442e75cf1da7b076f6dec4f16e4 Mon Sep 17 00:00:00 2001
From: Khizar1 <11738208+Khizar1@users.noreply.github.com>
Date: Sun, 12 Oct 2025 17:16:11 +0000
Subject: [PATCH 2/3] Update CHANGELOG.md

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ff978597cd5..3d293b132a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 ## Main
+-   Fix performance for non-contiguous NumPy array conversion in pybind vector converters. This change removes restrictive `py::array::c_style` flags and adds a runtime contiguity check, improving Pandas-to-Open3D conversion speed by up to ~50×. (issue #5250)(PR #7343).
 -   Corrected documentation for Link Open3D in C++ projects (broken links).
 -   Fix DLLs not being found in Python-package. Also prevent PATH from being searched for DLLs, except CUDA (PR #7108)
 -   Fix MSAA sample count not being copied when FilamentView is copied

From 07edf669b6f119f3de4eb1902f8e1b9539cbc2bd Mon Sep 17 00:00:00 2001
From: Khizar1 <11738208+Khizar1@users.noreply.github.com>
Date: Fri, 31 Oct 2025 05:33:19 +0000
Subject: [PATCH 3/3] Apply check_style.py to pybind/utility/eigen.cpp

---
 cpp/pybind/utility/eigen.cpp | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/cpp/pybind/utility/eigen.cpp b/cpp/pybind/utility/eigen.cpp
index b8e5981717b..87d055cf4bd 100644
--- a/cpp/pybind/utility/eigen.cpp
+++ b/cpp/pybind/utility/eigen.cpp
@@ -58,8 +58,7 @@ std::vector<EigenVector> py_array_to_vectors_double(
 }
 
 template <typename EigenVector>
-std::vector<EigenVector> py_array_to_vectors_int(
-        py::array_t<int> array) {
+std::vector<EigenVector> py_array_to_vectors_int(py::array_t<int> array) {
     if (!(array.flags() & (py::array::c_style))) {
         array = py::array_t<int, py::array::c_style>(array);
     }
@@ -78,8 +77,7 @@ std::vector<EigenVector> py_array_to_vectors_int(
 template <typename EigenVector,
           typename EigenAllocator = Eigen::aligned_allocator<EigenVector>>
 std::vector<EigenVector, EigenAllocator>
-py_array_to_vectors_int_eigen_allocator(
-        py::array_t<int> array) {
+py_array_to_vectors_int_eigen_allocator(py::array_t<int> array) {
     if (!(array.flags() & (py::array::c_style))) {
         array = py::array_t<int, py::array::c_style>(array);
     }
@@ -98,8 +96,7 @@ py_array_to_vectors_int_eigen_allocator(
 template <typename EigenVector,
           typename EigenAllocator = Eigen::aligned_allocator<EigenVector>>
 std::vector<EigenVector, EigenAllocator>
-py_array_to_vectors_int64_eigen_allocator(
-        py::array_t<int64_t> array) {
+py_array_to_vectors_int64_eigen_allocator(py::array_t<int64_t> array) {
     if (!(array.flags() & (py::array::c_style))) {
         array = py::array_t<int64_t, py::array::c_style>(array);
     }