blocked_rangeNd.h

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/*
    Copyright (c) 2017-2021 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.
*/
 
#ifndef __TBB_blocked_rangeNd_H
#define __TBB_blocked_rangeNd_H
 
#include <algorithm>    // std::any_of
#include <vector>
#include <cstddef>
#include <type_traits>  // std::is_same, std::enable_if
 
#include <oneapi/tbb/detail/_config.h>
#include <oneapi/tbb/detail/_namespace_injection.h>
#include <oneapi/tbb/detail/_range_common.h>
#include <oneapi/tbb/detail/_template_helpers.h>
 
#include <oneapi/tbb/blocked_range.h>
 
namespace tbb {
namespace detail {
namespace d1 {
 
/*
    The blocked_rangeNd_impl uses make_index_sequence<N> to automatically generate a ctor with
    exactly N arguments of the type tbb::blocked_range<Value>. Such ctor provides an opportunity
    to use braced-init-list parameters to initialize each dimension.
    Use of parameters, whose representation is a braced-init-list, but they're not
    std::initializer_list or a reference to one, produces a non-deduced context
    within template argument deduction.
 
    NOTE: blocked_rangeNd must be exactly a templated alias to the blocked_rangeNd_impl
    (and not e.g. a derived class), otherwise it would need to declare its own ctor
    facing the same problem that the impl class solves.
*/
 
#ifdef TBB_OLD_BLOCKED_RANGE_ND
 
template<typename Value, unsigned int N, typename = detail::make_index_sequence<N>>
    __TBB_requires(blocked_range_value<Value>)
class blocked_rangeNd_impl;
 
template<typename Value, unsigned int N, std::size_t... Is>
    __TBB_requires(blocked_range_value<Value>)
class blocked_rangeNd_impl<Value, N, detail::index_sequence<Is...>> {
public:
    using value_type = Value;
 
private:
    using dim_range_type = tbb::blocked_range<Value>;
 
public:
    blocked_rangeNd_impl() = delete;
 
    blocked_rangeNd_impl(
      //Value begin[N],
      Value end[N],
      typename tbb::blocked_range<value_type>::size_type grainsize
    ):
      my_dims() {
      for (int d=0; d<N; d++) {
        // my_dims.push_back( dim_range_type( begin[d], end[d], grainsize ) );
        my_dims.push_back( dim_range_type( 0, end[d], grainsize ) );
      }
      __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
    }
 
    static constexpr unsigned int ndims() { return N; }
 
    const tbb::blocked_range<value_type>& dim(unsigned int dimension) const {
        __TBB_ASSERT(dimension < N, "out of bound");
        __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
        return my_dims[dimension];
    }
 
    //------------------------------------------------------------------------
    // Methods that implement Range concept
    //------------------------------------------------------------------------
 
    bool empty() const {
        return std::any_of(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& d) {
            return d.empty();
        });
    }
 
    bool is_divisible() const {
        return std::any_of(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& d) {
            return d.is_divisible();
        });
    }
 
    blocked_rangeNd_impl(blocked_rangeNd_impl& r, proportional_split proportion) : my_dims(r.my_dims) {
        do_split(r, proportion);
        __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
    }
 
    blocked_rangeNd_impl(blocked_rangeNd_impl& r, split proportion) : my_dims(r.my_dims) {
        do_split(r, proportion);
        __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
    }
 
private:
    static_assert(N != 0, "zero dimensional blocked_rangeNd can't be constructed");
 
    std::vector<tbb::blocked_range<value_type>> my_dims;
 
    template<typename split_type>
    void do_split(blocked_rangeNd_impl& r, split_type proportion) {
        static_assert((std::is_same<split_type, split>::value || std::is_same<split_type, proportional_split>::value), "type of split object is incorrect");
        __TBB_ASSERT(r.is_divisible(), "can't split not divisible range");
 
        auto my_it = std::max_element(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& first, const tbb::blocked_range<value_type>& second) {
            return (first.size() * second.grainsize() < second.size() * first.grainsize());
        });
 
        auto r_it = r.my_dims.begin() + (my_it - my_dims.begin());
 
        my_it->my_begin = tbb::blocked_range<value_type>::do_split(*r_it, proportion);
 
        // (!(my_it->my_begin < r_it->my_end) && !(r_it->my_end < my_it->my_begin)) equals to
        // (my_it->my_begin == r_it->my_end), but we can't use operator== due to Value concept
        __TBB_ASSERT(!(my_it->my_begin < r_it->my_end) && !(r_it->my_end < my_it->my_begin),
                     "blocked_range has been split incorrectly");
    }
};
 
template<typename Value, unsigned int N>
using blocked_nd_range = blocked_rangeNd_impl<Value, N>;
 
#else
 
template<typename Value, unsigned int N, typename = detail::make_index_sequence<N>>
    __TBB_requires(blocked_range_value<Value>)
class blocked_nd_range_impl;
 
template<typename Value, unsigned int N, std::size_t... Is>
    __TBB_requires(blocked_range_value<Value>)
class blocked_nd_range_impl<Value, N, detail::index_sequence<Is...>> {
public:
    using value_type = Value;
 
private:
    using dim_range_type = tbb::blocked_range<Value>;
 
public:
    blocked_nd_range_impl() = delete;
 
    blocked_nd_range_impl(
      //Value begin[N],
      Value end[N],
      typename tbb::blocked_range<value_type>::size_type grainsize
    ):
      my_dims() {
      for (int d=0; d<N; d++) {
        // my_dims.push_back( dim_range_type( begin[d], end[d], grainsize ) );
        my_dims.push_back( dim_range_type( 0, end[d], grainsize ) );
      }
      __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
    }
 
    static constexpr unsigned int ndims() { return N; }
 
    const tbb::blocked_range<value_type>& dim(unsigned int dimension) const {
        __TBB_ASSERT(dimension < N, "out of bound");
        __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
        return my_dims[dimension];
    }
 
    //------------------------------------------------------------------------
    // Methods that implement Range concept
    //------------------------------------------------------------------------
 
    bool empty() const {
        return std::any_of(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& d) {
            return d.empty();
        });
    }
 
    bool is_divisible() const {
        return std::any_of(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& d) {
            return d.is_divisible();
        });
    }
 
    blocked_nd_range_impl(blocked_nd_range_impl& r, proportional_split proportion) : my_dims(r.my_dims) {
        do_split(r, proportion);
        __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
    }
 
    blocked_nd_range_impl(blocked_nd_range_impl& r, split proportion) : my_dims(r.my_dims) {
        do_split(r, proportion);
        __TBB_ASSERT(my_dims.size()==N, "range is not properly initialised" );
    }
 
private:
    static_assert(N != 0, "zero dimensional blocked_nd_range can't be constructed");
 
    std::vector<tbb::blocked_range<value_type>> my_dims;
 
    template<typename split_type>
    void do_split(blocked_nd_range_impl& r, split_type proportion) {
        static_assert((std::is_same<split_type, split>::value || std::is_same<split_type, proportional_split>::value), "type of split object is incorrect");
        __TBB_ASSERT(r.is_divisible(), "can't split not divisible range");
 
        auto my_it = std::max_element(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& first, const tbb::blocked_range<value_type>& second) {
            return (first.size() * second.grainsize() < second.size() * first.grainsize());
        });
 
        auto r_it = r.my_dims.begin() + (my_it - my_dims.begin());
 
        my_it->my_begin = tbb::blocked_range<value_type>::do_split(*r_it, proportion);
 
        // (!(my_it->my_begin < r_it->my_end) && !(r_it->my_end < my_it->my_begin)) equals to
        // (my_it->my_begin == r_it->my_end), but we can't use operator== due to Value concept
        __TBB_ASSERT(!(my_it->my_begin < r_it->my_end) && !(r_it->my_end < my_it->my_begin),
                     "blocked_range has been split incorrectly");
    }
};
 
template<typename Value, unsigned int N>
using blocked_nd_range = blocked_nd_range_impl<Value, N>;
 
#endif
} // namespace d1
} // namespace detail
 
inline namespace v1 {
using detail::d1::blocked_nd_range;
} // namespace v1
} // namespace tbb
 
#endif /* __TBB_blocked_rangeNd_H */