time-to-botec

Benchmark sampling in different programming languages
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dmskmax.c (2037B)

      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/dmskmax.h"
     20 #include "stdlib/math/base/assert/is_nan.h"
     21 #include "stdlib/math/base/assert/is_positive_zero.h"
     22 #include <stdint.h>
     23 
     24 /**
     25 * Computes the maximum value of a double-precision floating-point strided array according to a mask.
     26 *
     27 * @param N           number of indexed elements
     28 * @param X           input array
     29 * @param strideX     X stride length
     30 * @param Mask        mask array
     31 * @param strideMask  Mask stride length
     32 * @return            output value
     33 */
     34 double stdlib_strided_dmskmax( const int64_t N, const double *X, const int64_t strideX, const uint8_t *Mask, const int64_t strideMask ) {
     35 	double max;
     36 	int64_t ix;
     37 	int64_t im;
     38 	int64_t i;
     39 	double v;
     40 
     41 	if ( N <= 0 ) {
     42 		return 0.0 / 0.0; // NaN
     43 	}
     44 	if ( strideX < 0 ) {
     45 		ix = (1-N) * strideX;
     46 	} else {
     47 		ix = 0;
     48 	}
     49 	if ( strideMask < 0 ) {
     50 		im = (1-N) * strideMask;
     51 	} else {
     52 		im = 0;
     53 	}
     54 	for ( i = 0; i < N; i++ ) {
     55 		if ( Mask[ im ] == 0 ) {
     56 			break;
     57 		}
     58 		ix += strideX;
     59 		im += strideMask;
     60 	}
     61 	if ( i == N ) {
     62 		return 0.0 / 0.0; // NaN
     63 	}
     64 	max = X[ ix ];
     65 	if ( stdlib_base_is_nan( max ) ) {
     66 		return 0.0 / 0.0; // NaN
     67 	}
     68 	i += 1;
     69 	for (; i < N; i++ ) {
     70 		ix += strideX;
     71 		im += strideMask;
     72 		if ( Mask[ im ] ) {
     73 			continue;
     74 		}
     75 		v = X[ ix ];
     76 		if ( stdlib_base_is_nan( v ) ) {
     77 			return 0.0 / 0.0; // NaN
     78 		}
     79 		if ( v > max || ( v == max && stdlib_base_is_positive_zero( v ) ) ) {
     80 			max = v;
     81 		}
     82 	}
     83 	return max;
     84 }