Implements log2 and log10 (#1267)

* Implements log2 and log10

* Fixed docstrings for log10 and log2

dpctl/tensor/__init__.py

@@ -111,6 +111,8 @@
     less_equal,
     log,
     log1p,
+    log2,
+    log10,
     logical_and,
     logical_not,
     logical_or,
@@ -224,6 +226,8 @@
     "logical_or",
     "logical_xor",
     "log1p",
+    "log2",
+    "log10",
     "negative",
     "positive",
     "proj",

dpctl/tensor/_elementwise_funcs.py

@@ -563,10 +563,56 @@
 )
 
 # U22: ==== LOG2        (x)
-# FIXME: implement U22
+_log2_docstring_ = """
+log2(x, out=None, order='K')
+
+Computes the base-2 logarithm for each element `x_i` of input array `x`.
+
+Args:
+    x (usm_ndarray):
+        Input array, expected to have numeric data type.
+    out ({None, usm_ndarray}, optional):
+        Output array to populate.
+        Array have the correct shape and the expected data type.
+    order ("C","F","A","K", optional):
+        Memory layout of the newly output array, if parameter `out` is `None`.
+        Default: "K".
+Returns:
+    usm_narray:
+        An array containing the base-2 logarithm of `x`.
+        The data type of the returned array is determined by the
+        Type Promotion Rules.
+"""
+
+log2 = UnaryElementwiseFunc(
+    "log2", ti._log2_result_type, ti._log2, _log2_docstring_
+)
 
 # U23: ==== LOG10       (x)
-# FIXME: implement U23
+_log10_docstring_ = """
+log10(x, out=None, order='K')
+
+Computes the base-10 logarithm for each element `x_i` of input array `x`.
+
+Args:
+    x (usm_ndarray):
+        Input array, expected to have numeric data type.
+    out ({None, usm_ndarray}, optional):
+        Output array to populate.
+        Array have the correct shape and the expected data type.
+    order ("C","F","A","K", optional):
+        Memory layout of the newly output array, if parameter `out` is `None`.
+        Default: "K".
+Returns:
+    usm_narray:
+        An array containing the base-1- logarithm of `x`.
+        The data type of the returned array is determined by the
+        Type Promotion Rules.
+"""
+
+log10 = UnaryElementwiseFunc(
+    "log10", ti._log10_result_type, ti._log10, _log10_docstring_
+)
 
 # B15: ==== LOGADDEXP   (x1, x2)
 # FIXME: implement B15

dpctl/tensor/libtensor/include/kernels/elementwise_functions/log10.hpp

@@ -0,0 +1,224 @@
+//=== log10.hpp -   Unary function LOG10                     ------
+//*-C++-*--/===//
+//
+//                      Data Parallel Control (dpctl)
+//
+// Copyright 2020-2023 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 LOG10(x) function.
+//===---------------------------------------------------------------------===//
+
+#pragma once
+#include <CL/sycl.hpp>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <type_traits>
+
+#include "kernels/elementwise_functions/common.hpp"
+
+#include "utils/offset_utils.hpp"
+#include "utils/type_dispatch.hpp"
+#include "utils/type_utils.hpp"
+#include <pybind11/pybind11.h>
+
+namespace dpctl
+{
+namespace tensor
+{
+namespace kernels
+{
+namespace log10
+{
+
+namespace py = pybind11;
+namespace td_ns = dpctl::tensor::type_dispatch;
+
+using dpctl::tensor::type_utils::is_complex;
+using dpctl::tensor::type_utils::vec_cast;
+
+template <typename argT, typename resT> struct Log10Functor
+{
+
+    // is function constant for given argT
+    using is_constant = typename std::false_type;
+    // constant value, if constant
+    // constexpr resT constant_value = resT{};
+    // is function defined for sycl::vec
+    using supports_vec = typename std::negation<
+        std::disjunction<is_complex<resT>, is_complex<argT>>>;
+    // do both argTy and resTy support sugroup store/load operation
+    using supports_sg_loadstore = typename std::negation<
+        std::disjunction<is_complex<resT>, is_complex<argT>>>;
+
+    resT operator()(const argT &in)
+    {
+        if constexpr (is_complex<argT>::value) {
+            using realT = typename argT::value_type;
+            return (std::log(in) / std::log(realT{10}));
+        }
+        else {
+            return std::log10(in);
+        }
+    }
+
+    template <int vec_sz>
+    sycl::vec<resT, vec_sz> operator()(const sycl::vec<argT, vec_sz> &in)
+    {
+        auto const &res_vec = sycl::log10(in);
+        using deducedT = typename std::remove_cv_t<
+            std::remove_reference_t<decltype(res_vec)>>::element_type;
+        if constexpr (std::is_same_v<resT, deducedT>) {
+            return res_vec;
+        }
+        else {
+            return vec_cast<resT, deducedT, vec_sz>(res_vec);
+        }
+    }
+};
+
+template <typename argTy,
+          typename resTy = argTy,
+          unsigned int vec_sz = 4,
+          unsigned int n_vecs = 2>
+using Log10ContigFunctor =
+    elementwise_common::UnaryContigFunctor<argTy,
+                                           resTy,
+                                           Log10Functor<argTy, resTy>,
+                                           vec_sz,
+                                           n_vecs>;
+
+template <typename argTy, typename resTy, typename IndexerT>
+using Log10StridedFunctor = elementwise_common::
+    UnaryStridedFunctor<argTy, resTy, IndexerT, Log10Functor<argTy, resTy>>;
+
+template <typename T> struct Log10OutputType
+{
+    using value_type = typename std::disjunction< // disjunction is C++17
+                                                  // feature, supported by DPC++
+        td_ns::TypeMapResultEntry<T, sycl::half, sycl::half>,
+        td_ns::TypeMapResultEntry<T, float, float>,
+        td_ns::TypeMapResultEntry<T, double, double>,
+        td_ns::TypeMapResultEntry<T, std::complex<float>, std::complex<float>>,
+        td_ns::
+            TypeMapResultEntry<T, std::complex<double>, std::complex<double>>,
+        td_ns::DefaultResultEntry<void>>::result_type;
+};
+
+typedef sycl::event (*log10_contig_impl_fn_ptr_t)(
+    sycl::queue,
+    size_t,
+    const char *,
+    char *,
+    const std::vector<sycl::event> &);
+
+template <typename T1, typename T2, unsigned int vec_sz, unsigned int n_vecs>
+class log10_contig_kernel;
+
+template <typename argTy>
+sycl::event log10_contig_impl(sycl::queue exec_q,
+                              size_t nelems,
+                              const char *arg_p,
+                              char *res_p,
+                              const std::vector<sycl::event> &depends = {})
+{
+    return elementwise_common::unary_contig_impl<
+        argTy, Log10OutputType, Log10ContigFunctor, log10_contig_kernel>(
+        exec_q, nelems, arg_p, res_p, depends);
+}
+
+template <typename fnT, typename T> struct Log10ContigFactory
+{
+    fnT get()
+    {
+        if constexpr (std::is_same_v<typename Log10OutputType<T>::value_type,
+                                     void>) {
+            fnT fn = nullptr;
+            return fn;
+        }
+        else {
+            fnT fn = log10_contig_impl<T>;
+            return fn;
+        }
+    }
+};
+
+template <typename fnT, typename T> struct Log10TypeMapFactory
+{
+    /*! @brief get typeid for output type of std::log10(T x) */
+    std::enable_if_t<std::is_same<fnT, int>::value, int> get()
+    {
+        using rT = typename Log10OutputType<T>::value_type;
+        ;
+        return td_ns::GetTypeid<rT>{}.get();
+    }
+};
+
+template <typename T1, typename T2, typename T3> class log10_strided_kernel;
+
+typedef sycl::event (*log10_strided_impl_fn_ptr_t)(
+    sycl::queue,
+    size_t,
+    int,
+    const py::ssize_t *,
+    const char *,
+    py::ssize_t,
+    char *,
+    py::ssize_t,
+    const std::vector<sycl::event> &,
+    const std::vector<sycl::event> &);
+
+template <typename argTy>
+sycl::event
+log10_strided_impl(sycl::queue exec_q,
+                   size_t nelems,
+                   int nd,
+                   const py::ssize_t *shape_and_strides,
+                   const char *arg_p,
+                   py::ssize_t arg_offset,
+                   char *res_p,
+                   py::ssize_t res_offset,
+                   const std::vector<sycl::event> &depends,
+                   const std::vector<sycl::event> &additional_depends)
+{
+    return elementwise_common::unary_strided_impl<
+        argTy, Log10OutputType, Log10StridedFunctor, log10_strided_kernel>(
+        exec_q, nelems, nd, shape_and_strides, arg_p, arg_offset, res_p,
+        res_offset, depends, additional_depends);
+}
+
+template <typename fnT, typename T> struct Log10StridedFactory
+{
+    fnT get()
+    {
+        if constexpr (std::is_same_v<typename Log10OutputType<T>::value_type,
+                                     void>) {
+            fnT fn = nullptr;
+            return fn;
+        }
+        else {
+            fnT fn = log10_strided_impl<T>;
+            return fn;
+        }
+    }
+};
+
+} // namespace log10
+} // namespace kernels
+} // namespace tensor
+} // namespace dpctl