48 lines
1.6 KiB
C
48 lines
1.6 KiB
C
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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2020 The Stdlib Authors.
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*
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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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*/
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#include "stdlib/stats/base/smeankbn.h"
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#include "stdlib/blas/ext/base/ssum.h"
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#include <stdint.h>
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/**
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* Computes the arithmetic mean of a single-precision floating-point strided array using an improved Kahan–Babuška algorithm.
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*
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* ## Method
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*
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* - This implementation uses an "improved Kahan–Babuška algorithm", as described by Neumaier (1974).
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*
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* ## References
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*
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* - Neumaier, Arnold. 1974. "Rounding Error Analysis of Some Methods for Summing Finite Sums." _Zeitschrift Für Angewandte Mathematik Und Mechanik_ 54 (1): 39–51. doi:[10.1002/zamm.19740540106](https://doi.org/10.1002/zamm.19740540106).
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*
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* @param N number of indexed elements
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* @param X input array
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* @param stride stride length
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* @return output value
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*/
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float stdlib_strided_smeankbn( const int64_t N, const float *X, const int64_t stride ) {
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if ( N <= 0 ) {
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return 0.0 / 0.0; // NaN
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}
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if ( N == 1 || stride == 0 ) {
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return X[ 0 ];
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}
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return (double)stdlib_strided_ssum( N, X, stride ) / (double)N;
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}
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