83 lines
2.0 KiB
C
83 lines
2.0 KiB
C
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2020 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "stdlib/stats/base/snanmskmax.h"
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#include "stdlib/math/base/assert/is_nanf.h"
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#include "stdlib/math/base/assert/is_positive_zerof.h"
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#include <stdint.h>
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/**
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* Computes the maximum value of a single-precision floating-point strided array according to a mask, ignoring `NaN` values.
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*
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* @param N number of indexed elements
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* @param X input array
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* @param strideX X stride length
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* @param Mask mask array
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* @param strideMask Mask stride length
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* @return output value
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*/
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float stdlib_strided_snanmskmax( const int64_t N, const float *X, const int64_t strideX, const uint8_t *Mask, const int64_t strideMask ) {
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int64_t ix;
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int64_t im;
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int64_t i;
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float max;
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float v;
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if ( N <= 0 ) {
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return 0.0f / 0.0f; // NaN
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}
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if ( strideX < 0 ) {
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ix = (1-N) * strideX;
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} else {
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ix = 0;
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}
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if ( strideMask < 0 ) {
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im = (1-N) * strideMask;
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} else {
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im = 0;
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}
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for ( i = 0; i < N; i++ ) {
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v = X[ ix ];
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if ( v == v && Mask[ im ] == 0 ) {
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break;
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}
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ix += strideX;
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im += strideMask;
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}
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if ( i == N ) {
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return 0.0f / 0.0f; // NaN
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}
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max = v;
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i += 1;
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for (; i < N; i++ ) {
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ix += strideX;
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im += strideMask;
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if ( Mask[ im ] ) {
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continue;
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}
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v = X[ ix ];
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if ( stdlib_base_is_nanf( v ) ) {
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continue;
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}
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if ( v > max || ( v == max && stdlib_base_is_positive_zerof( v ) ) ) {
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max = v;
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}
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}
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return max;
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}
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