sdsnanmeanors.c (1532B)
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/sdsnanmeanors.h" 20 #include <stdint.h> 21 22 /** 23 * Computes the arithmetic mean of a single-precision floating-point strided array, ignoring `NaN` values and 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_sdsnanmeanors( const int64_t N, const float *X, const int64_t stride ) { 31 double sum; 32 int64_t ix; 33 int64_t i; 34 int64_t n; 35 double v; 36 37 if ( N <= 0 ) { 38 return 0.0 / 0.0; // NaN 39 } 40 if ( N == 1 || stride == 0 ) { 41 return X[ 0 ]; 42 } 43 if ( stride < 0 ) { 44 ix = (1-N) * stride; 45 } else { 46 ix = 0; 47 } 48 sum = 0.0; 49 n = 0; 50 for ( i = 0; i < N; i++ ) { 51 v = (double)X[ ix ]; 52 if ( v == v ) { 53 sum += v; 54 n += 1; 55 } 56 ix += stride; 57 } 58 if ( n == 0 ) { 59 return 0.0 / 0.0; // NaN 60 } 61 return sum / (double)n; 62 }