sdsmeanors.c (1378B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2020 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 #include "stdlib/stats/base/sdsmeanors.h" 20 #include <stdint.h> 21 22 /** 23 * Computes the arithmetic mean of a single-precision floating-point strided array using ordinary recursive summation with extended accumulation. 24 * 25 * @param N number of indexed elements 26 * @param X input array 27 * @param stride stride length 28 * @return output value 29 */ 30 float stdlib_strided_sdsmeanors( const int64_t N, const float *X, const int64_t stride ) { 31 double sum; 32 int64_t ix; 33 int64_t i; 34 35 if ( N <= 0 ) { 36 return 0.0 / 0.0; // NaN 37 } 38 if ( N == 1 || stride == 0 ) { 39 return X[ 0 ]; 40 } 41 if ( stride < 0 ) { 42 ix = (1-N) * stride; 43 } else { 44 ix = 0; 45 } 46 sum = 0.0; 47 for ( i = 0; i < N; i++ ) { 48 sum += (double)X[ ix ]; 49 ix += stride; 50 } 51 return sum / (double)N; 52 }