main.c (1684B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 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/ndarray/base/iteration_order.h" 20 #include <stdint.h> 21 22 /** 23 * Determines array iteration order given a stride array. 24 * 25 * ## Notes 26 * 27 * The function returns one of the following values: 28 * 29 * - `1`: left-to-right iteration order (strides are all nonnegative). 30 * - `-1`: right-to-left iteration order (strides are all negative). 31 * - `0`: unordered (strides are of mixed sign). 32 * 33 * @param ndims number of dimensions 34 * @param strides array strides 35 * @return iteration order 36 * 37 * @example 38 * #include "stdlib/ndarray/base/iteration_order.h" 39 * 40 * uint64_t ndims = 2; 41 * int64_t strides[] = { 2, 1 }; 42 * 43 * int8_t o = stdlib_ndarray_iteration_order( ndims, strides ); 44 * // returns 1 45 */ 46 int8_t stdlib_ndarray_iteration_order( int64_t ndims, int64_t *strides ) { 47 int64_t cnt; 48 int64_t i; 49 50 cnt = 0; 51 for ( i = 0; i < ndims; i++ ) { 52 if ( strides[ i ] < 0 ) { 53 cnt += 1; 54 } 55 } 56 if ( cnt == 0 ) { 57 // All nonnegative strides: 58 return 1; 59 } 60 if ( cnt == ndims ) { 61 // All negative strides: 62 return -1; 63 } 64 // Strides of mixed signs: 65 return 0; 66 }