Implements dpctl.tensor.nextafter per array API

dpctl/tensor/CMakeLists.txt

@@ -76,6 +76,7 @@ set(_elementwise_sources
     ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions/minimum.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions/multiply.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions/negative.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions/nextafter.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions/not_equal.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions/positive.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions/pow.cpp

dpctl/tensor/__init__.py

@@ -152,6 +152,7 @@
     minimum,
     multiply,
     negative,
+    nextafter,
     not_equal,
     positive,
     pow,
@@ -371,4 +372,5 @@
     "cumulative_logsumexp",
     "cumulative_prod",
     "cumulative_sum",
+    "nextafter",
 ]

dpctl/tensor/_elementwise_funcs.py

@@ -1487,6 +1487,40 @@
 )
 del _negative_docstring_
 
+# B28: ==== NEXTAFTER    (x1, x2)
+_nextafter_docstring_ = r"""
+nextafter(x1, x2, /, \*, out=None, order='K')
+
+Calculates the next floating-point value after element `x1_i` of the input
+array `x1` toward the respective element `x2_i` of the input array `x2`.
+
+Args:
+    x1 (usm_ndarray):
+        First input array.
+    x2 (usm_ndarray):
+        Second input array.
+    out (Union[usm_ndarray, None], optional):
+        Output array to populate.
+        Array must have the correct shape and the expected data type.
+    order ("C","F","A","K", optional):
+        Memory layout of the new output array, if parameter
+        `out` is ``None``.
+        Default: "K".
+
+Returns:
+    usm_ndarray:
+        An array containing the element-wise next representable values of `x1`
+        in the direction of `x2`. The data type of the returned array is
+        determined by the Type Promotion Rules.
+"""
+nextafter = BinaryElementwiseFunc(
+    "nextafter",
+    ti._nextafter_result_type,
+    ti._nextafter,
+    _nextafter_docstring_,
+)
+del _nextafter_docstring_
+
 # B20: ==== NOT_EQUAL   (x1, x2)
 _not_equal_docstring_ = r"""
 not_equal(x1, x2, /, \*, out=None, order='K')

dpctl/tensor/libtensor/include/kernels/elementwise_functions/nextafter.hpp

@@ -0,0 +1,217 @@
+//=== NEXTAFTER.hpp -   Binary function NEXTAFTER  ------ *-C++-*--/===//
+//
+//                      Data Parallel Control (dpctl)
+//
+// Copyright 2020-2024 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//===---------------------------------------------------------------------===//
+///
+/// \file
+/// This file defines kernels for elementwise evaluation of NEXTAFTER(x1, x2)
+/// function.
+//===---------------------------------------------------------------------===//
+
+#pragma once
+#include <cstddef>
+#include <cstdint>
+#include <sycl/sycl.hpp>
+#include <type_traits>
+
+#include "utils/offset_utils.hpp"
+#include "utils/type_dispatch_building.hpp"
+#include "utils/type_utils.hpp"
+
+#include "kernels/dpctl_tensor_types.hpp"
+#include "kernels/elementwise_functions/common.hpp"
+
+namespace dpctl
+{
+namespace tensor
+{
+namespace kernels
+{
+namespace nextafter
+{
+
+namespace td_ns = dpctl::tensor::type_dispatch;
+namespace tu_ns = dpctl::tensor::type_utils;
+
+template <typename argT1, typename argT2, typename resT> struct NextafterFunctor
+{
+
+    using supports_sg_loadstore = std::true_type;
+    using supports_vec = std::true_type;
+
+    resT operator()(const argT1 &in1, const argT2 &in2) const
+    {
+        return sycl::nextafter(in1, in2);
+    }
+
+    template <int vec_sz>
+    sycl::vec<resT, vec_sz>
+    operator()(const sycl::vec<argT1, vec_sz> &in1,
+               const sycl::vec<argT2, vec_sz> &in2) const
+    {
+        auto res = sycl::nextafter(in1, in2);
+        if constexpr (std::is_same_v<resT,
+                                     typename decltype(res)::element_type>) {
+            return res;
+        }
+        else {
+            using dpctl::tensor::type_utils::vec_cast;
+
+            return vec_cast<resT, typename decltype(res)::element_type, vec_sz>(
+                res);
+        }
+    }
+};
+
+template <typename argT1,
+          typename argT2,
+          typename resT,
+          unsigned int vec_sz = 4,
+          unsigned int n_vecs = 2,
+          bool enable_sg_loadstore = true>
+using NextafterContigFunctor = elementwise_common::BinaryContigFunctor<
+    argT1,
+    argT2,
+    resT,
+    NextafterFunctor<argT1, argT2, resT>,
+    vec_sz,
+    n_vecs,
+    enable_sg_loadstore>;
+
+template <typename argT1, typename argT2, typename resT, typename IndexerT>
+using NextafterStridedFunctor = elementwise_common::BinaryStridedFunctor<
+    argT1,
+    argT2,
+    resT,
+    IndexerT,
+    NextafterFunctor<argT1, argT2, resT>>;
+
+template <typename T1, typename T2> struct NextafterOutputType
+{
+    using value_type = typename std::disjunction< // disjunction is C++17
+                                                  // feature, supported by DPC++
+        td_ns::BinaryTypeMapResultEntry<T1,
+                                        sycl::half,
+                                        T2,
+                                        sycl::half,
+                                        sycl::half>,
+        td_ns::BinaryTypeMapResultEntry<T1, float, T2, float, float>,
+        td_ns::BinaryTypeMapResultEntry<T1, double, T2, double, double>,
+        td_ns::DefaultResultEntry<void>>::result_type;
+};
+
+template <typename argT1,
+          typename argT2,
+          typename resT,
+          unsigned int vec_sz,
+          unsigned int n_vecs>
+class nextafter_contig_kernel;
+
+template <typename argTy1, typename argTy2>
+sycl::event nextafter_contig_impl(sycl::queue &exec_q,
+                                  size_t nelems,
+                                  const char *arg1_p,
+                                  ssize_t arg1_offset,
+                                  const char *arg2_p,
+                                  ssize_t arg2_offset,
+                                  char *res_p,
+                                  ssize_t res_offset,
+                                  const std::vector<sycl::event> &depends = {})
+{
+    return elementwise_common::binary_contig_impl<
+        argTy1, argTy2, NextafterOutputType, NextafterContigFunctor,
+        nextafter_contig_kernel>(exec_q, nelems, arg1_p, arg1_offset, arg2_p,
+                                 arg2_offset, res_p, res_offset, depends);
+}
+
+template <typename fnT, typename T1, typename T2> struct NextafterContigFactory
+{
+    fnT get()
+    {
+        if constexpr (std::is_same_v<
+                          typename NextafterOutputType<T1, T2>::value_type,
+                          void>)
+        {
+            fnT fn = nullptr;
+            return fn;
+        }
+        else {
+            fnT fn = nextafter_contig_impl<T1, T2>;
+            return fn;
+        }
+    }
+};
+
+template <typename fnT, typename T1, typename T2> struct NextafterTypeMapFactory
+{
+    /*! @brief get typeid for output type of std::nextafter(T1 x, T2 y) */
+    std::enable_if_t<std::is_same<fnT, int>::value, int> get()
+    {
+        using rT = typename NextafterOutputType<T1, T2>::value_type;
+        ;
+        return td_ns::GetTypeid<rT>{}.get();
+    }
+};
+
+template <typename T1, typename T2, typename resT, typename IndexerT>
+class nextafter_strided_kernel;
+
+template <typename argTy1, typename argTy2>
+sycl::event
+nextafter_strided_impl(sycl::queue &exec_q,
+                       size_t nelems,
+                       int nd,
+                       const ssize_t *shape_and_strides,
+                       const char *arg1_p,
+                       ssize_t arg1_offset,
+                       const char *arg2_p,
+                       ssize_t arg2_offset,
+                       char *res_p,
+                       ssize_t res_offset,
+                       const std::vector<sycl::event> &depends,
+                       const std::vector<sycl::event> &additional_depends)
+{
+    return elementwise_common::binary_strided_impl<
+        argTy1, argTy2, NextafterOutputType, NextafterStridedFunctor,
+        nextafter_strided_kernel>(exec_q, nelems, nd, shape_and_strides, arg1_p,
+                                  arg1_offset, arg2_p, arg2_offset, res_p,
+                                  res_offset, depends, additional_depends);
+}
+
+template <typename fnT, typename T1, typename T2> struct NextafterStridedFactory
+{
+    fnT get()
+    {
+        if constexpr (std::is_same_v<
+                          typename NextafterOutputType<T1, T2>::value_type,
+                          void>)
+        {
+            fnT fn = nullptr;
+            return fn;
+        }
+        else {
+            fnT fn = nextafter_strided_impl<T1, T2>;
+            return fn;
+        }
+    }
+};
+
+} // namespace nextafter
+} // namespace kernels
+} // namespace tensor
+} // namespace dpctl

dpctl/tensor/libtensor/source/elementwise_functions/elementwise_common.cpp

@@ -75,6 +75,7 @@
 #include "minimum.hpp"
 #include "multiply.hpp"
 #include "negative.hpp"
+#include "nextafter.hpp"
 #include "not_equal.hpp"
 #include "positive.hpp"
 #include "pow.hpp"
@@ -158,6 +159,7 @@ void init_elementwise_functions(py::module_ m)
     init_maximum(m);
     init_minimum(m);
     init_multiply(m);
+    init_nextafter(m);
     init_negative(m);
     init_not_equal(m);
     init_positive(m);