ext: Updated Pybind11 to version 2.4.1.

This updates Pybind11 from version 2.2.1 to version 2.4.1. This fixes
warning/error received when "<experiment/optional>" is used when
compiling using c++14 with clang. It should be noted that
"ext/pybind11/include/pybind11/std.h" has been changed to include a fix
added by commit ba42457254cc362eddc099f22b60d469cc6369e0. This is
necessary to avoid build errors.

Built: Linux (gcc, c++11) and MacOS (clang, c++14).
Tested: Ran quick tests for X86, ARM, and RISC-V.
Deprecates: https://gem5-review.googlesource.com/c/public/gem5/+/21019
Change-Id: Ie9783511cb6be50136076a55330e645f4f36d075
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21119
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

1 files changed, 23 insertions, 3 deletions

diff --git a/ext/pybind11/docs/advanced/pycpp/numpy.rst b/ext/pybind11/docs/advanced/pycpp/numpy.rst
index 98b0c25b9..458f99e97 100644
--- a/ext/pybind11/docs/advanced/pycpp/numpy.rst
+++ b/ext/pybind11/docs/advanced/pycpp/numpy.rst
@@ -41,7 +41,7 @@ completely avoid copy operations with Python expressions like
                 py::format_descriptor<float>::format(), /* Python struct-style format descriptor */
                 2,                                      /* Number of dimensions */
                 { m.rows(), m.cols() },                 /* Buffer dimensions */
-                { sizeof(float) * m.rows(),             /* Strides (in bytes) for each index */
+                { sizeof(float) * m.cols(),             /* Strides (in bytes) for each index */
                   sizeof(float) }
             );
         });
@@ -261,7 +261,7 @@ simply using ``vectorize``).
     namespace py = pybind11;
 
     py::array_t<double> add_arrays(py::array_t<double> input1, py::array_t<double> input2) {
-        auto buf1 = input1.request(), buf2 = input2.request();
+        py::buffer_info buf1 = input1.request(), buf2 = input2.request();
 
         if (buf1.ndim != 1 || buf2.ndim != 1)
             throw std::runtime_error("Number of dimensions must be one");
@@ -272,7 +272,7 @@ simply using ``vectorize``).
         /* No pointer is passed, so NumPy will allocate the buffer */
         auto result = py::array_t<double>(buf1.size);
 
-        auto buf3 = result.request();
+        py::buffer_info buf3 = result.request();
 
         double *ptr1 = (double *) buf1.ptr,
                *ptr2 = (double *) buf2.ptr,
@@ -364,3 +364,23 @@ uses of ``py::array``:
 
     The file :file:`tests/test_numpy_array.cpp` contains additional examples
     demonstrating the use of this feature.
+
+Ellipsis
+========
+
+Python 3 provides a convenient ``...`` ellipsis notation that is often used to
+slice multidimensional arrays. For instance, the following snippet extracts the
+middle dimensions of a tensor with the first and last index set to zero.
+
+.. code-block:: python
+
+   a = # a NumPy array
+   b = a[0, ..., 0]
+
+The function ``py::ellipsis()`` function can be used to perform the same
+operation on the C++ side:
+
+.. code-block:: cpp
+
+   py::array a = /* A NumPy array */;
+   py::array b = a[py::make_tuple(0, py::ellipsis(), 0)];