sminabs.c (1485B)
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/sminabs.h" 20 #include "stdlib/math/base/assert/is_nanf.h" 21 #include <stdint.h> 22 #include <math.h> 23 24 /** 25 * Computes the minimum absolute value of a single-precision floating-point strided array. 26 * 27 * @param N number of indexed elements 28 * @param X input array 29 * @param stride stride length 30 * @return output value 31 */ 32 float stdlib_strided_sminabs( const int64_t N, const float *X, const int64_t stride ) { 33 int64_t ix; 34 int64_t i; 35 float min; 36 float v; 37 38 if ( N <= 0 ) { 39 return 0.0 / 0.0; // NaN 40 } 41 if ( N == 1 || stride == 0 ) { 42 return fabsf( X[ 0 ] ); 43 } 44 if ( stride < 0 ) { 45 ix = (1-N) * stride; 46 } else { 47 ix = 0; 48 } 49 min = fabsf( X[ ix ] ); 50 for ( i = 1; i < N; i++ ) { 51 ix += stride; 52 v = fabsf( X[ ix ] ); 53 if ( stdlib_base_is_nanf( v ) ) { 54 return v; 55 } 56 if ( v < min ) { 57 min = v; 58 } 59 } 60 return min; 61 }