44 lines
1.6 KiB
C++
44 lines
1.6 KiB
C++
// Copyright 2010-2025 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Fast summation of arrays (vectors, spans) of numbers.
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//
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// Speed: up to 2x faster than Eigen for float arrays with ~100 elements or more
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// (as of 2023-05).
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// Precision: Better or comparable precision to std::accumulate<> on the same
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// value type. That said, the precision is inferior to precise sum
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// algorithm such as ::AccurateSum.
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#ifndef ORTOOLS_UTIL_VECTOR_SUM_H_
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#define ORTOOLS_UTIL_VECTOR_SUM_H_
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#include "absl/types/span.h"
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#include "ortools/util/vector_sum_internal.h"
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namespace operations_research {
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// Computes the sum of `values`, assuming that the first element of `values` is
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// aligned to 16 bytes.
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inline float AlignedVectorSum(absl::Span<const float> values) {
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return internal::VectorSum<4, 4, /*assume_aligned_at_start=*/true>(values);
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}
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// Computes the sum of `values` without assuming anything.
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inline float VectorSum(absl::Span<const float> values) {
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return internal::VectorSum<4, 4, /*assume_aligned_at_start=*/false>(values);
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}
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} // namespace operations_research
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#endif // ORTOOLS_UTIL_VECTOR_SUM_H_
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