cswap.c (1694B)
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/blas/base/cswap.h" 20 21 /** 22 * Interchanges two complex single-precision floating-point vectors. 23 * 24 * @param N number of elements to swap 25 * @param X first input array 26 * @param strideX X stride length 27 * @param Y second input array 28 * @param strideY Y stride length 29 */ 30 void c_cswap( const int N, void *X, const int strideX, void *Y, const int strideY ) { 31 float *x = (float *)X; 32 float *y = (float *)Y; 33 float tmp; 34 int ix; 35 int iy; 36 int i; 37 int j; 38 39 if ( N <= 0 ) { 40 return; 41 } 42 if ( strideX == 1 && strideY == 1 ) { 43 for ( i = 0; i < N*2; i += 2 ) { 44 tmp = x[ i ]; 45 x[ i ] = y[ i ]; 46 y[ i ] = tmp; 47 48 j = i + 1; 49 tmp = x[ j ]; 50 x[ j ] = y[ j ]; 51 y[ j ] = tmp; 52 } 53 return; 54 } 55 if ( strideX < 0 ) { 56 ix = 2 * (1-N) * strideX; 57 } else { 58 ix = 0; 59 } 60 if ( strideY < 0 ) { 61 iy = 2 * (1-N) * strideY; 62 } else { 63 iy = 0; 64 } 65 for ( i = 0; i < N; i++ ) { 66 tmp = x[ ix ]; 67 x[ ix ] = y[ iy ]; 68 y[ iy ] = tmp; 69 70 tmp = x[ ix+1 ]; 71 x[ ix+1 ] = y[ iy+1 ]; 72 y[ iy+1 ] = tmp; 73 74 ix += strideX * 2; 75 iy += strideY * 2; 76 } 77 return; 78 }