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median.cpp
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139 lines (119 loc) · 4.03 KB
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/*******************************************************
* Copyright (c) 2014, ArrayFire
* All rights reserved.
*
* This file is distributed under 3-clause BSD license.
* The complete license agreement can be obtained at:
* http://arrayfire.com/licenses/BSD-3-Clause
********************************************************/
#include <af/dim4.hpp>
#include <af/defines.h>
#include <af/statistics.h>
#include <af/index.h>
#include <af/arith.h>
#include <af/data.h>
#include <handle.hpp>
#include <err_common.hpp>
#include <backend.hpp>
#include <sort.hpp>
#include <math.hpp>
#include <cast.hpp>
using namespace detail;
using af::dim4;
template<typename T>
static T median(const af_array& in)
{
const Array<T> input = getArray<T>(in);
dim_type nElems = input.elements();
double mid = (nElems + 1) / 2;
af_seq mdSpan[1]= {af_make_seq(mid-1, mid, 1)};
dim4 dims(nElems, 1, 1, 1);
af_array temp = 0;
AF_CHECK(af_moddims(&temp, in, 1, dims.get()));
Array<T> sortedArr = sort<T, true>(input, 0);
T result;
T resPtr[2];
af_array res = 0;
AF_CHECK(af_index(&res, getHandle<T>(sortedArr), 1, mdSpan));
AF_CHECK(af_get_data_ptr((void*)&resPtr, res));
if (nElems % 2 == 1) {
result = *resPtr;
} else {
result = division(*resPtr + *(resPtr+1), 2);
}
AF_CHECK(af_destroy_array(res));
AF_CHECK(af_destroy_array(temp));
return result;
}
template<typename T>
static af_array median(const af_array& in, dim_type dim)
{
const Array<T> input = getArray<T>(in);
Array<T> sortedIn = sort<T, true>(input, dim);
int nElems = input.elements();
double mid = (nElems + 1) / 2;
af_array left = 0;
af_seq slices[4] = {af_span, af_span, af_span, af_span};
slices[dim] = af_make_seq(mid-1.0, mid-1.0, 1.0);
AF_CHECK(af_index(&left, getHandle<T>(sortedIn), input.ndims(), slices));
if (nElems % 2 == 1) {
// mid-1 is our guy
return left;
} else {
// ((mid-1)+mid)/2 is our guy
dim4 dims = input.dims();
af_array right = 0;
slices[dim] = af_make_seq(mid, mid, 1.0);
AF_CHECK(af_index(&right, getHandle<T>(sortedIn), dims.ndims(), slices));
af_array sumarr = 0;
af_array carr = 0;
af_array result = 0;
AF_CHECK(af_constant(&carr, 0.5, dims.ndims(), dims.get(), input.getType()));
AF_CHECK(af_add(&sumarr, left, right, false));
AF_CHECK(af_mul(&result, sumarr, carr, false));
AF_CHECK(af_destroy_array(left));
AF_CHECK(af_destroy_array(right));
AF_CHECK(af_destroy_array(sumarr));
AF_CHECK(af_destroy_array(carr));
return result;
}
}
af_err af_median_all(double *realVal, double *imagVal, const af_array in)
{
try {
ArrayInfo info = getInfo(in);
af_dtype type = info.getType();
switch(type) {
case f64: *realVal = median<double>(in); break;
case f32: *realVal = median<float >(in); break;
case s32: *realVal = median<int >(in); break;
case u32: *realVal = median<uint >(in); break;
case u8: *realVal = median<uchar >(in); break;
case b8: *realVal = median<char >(in); break;
default : TYPE_ERROR(1, type);
}
}
CATCHALL;
return AF_SUCCESS;
}
af_err af_median(af_array* out, const af_array in, dim_type dim)
{
try {
ARG_ASSERT(2, (dim>=0 && dim<=0));
af_array output = 0;
ArrayInfo info = getInfo(in);
af_dtype type = info.getType();
switch(type) {
case f64: output = median<double>(in, dim); break;
case f32: output = median<float >(in, dim); break;
case s32: output = median<int >(in, dim); break;
case u32: output = median<uint >(in, dim); break;
case u8: output = median<uchar >(in, dim); break;
case b8: output = median<char >(in, dim); break;
default : TYPE_ERROR(1, type);
}
std::swap(*out, output);
}
CATCHALL;
return AF_SUCCESS;
}