Brecht Van Lommel
9cfc7967dd
* Replace license text in headers with SPDX identifiers. * Remove specific license info from outdated readme.txt, instead leave details to the source files. * Add list of SPDX license identifiers used, and corresponding license texts. * Update copyright dates while we're at it. Ref D14069, T95597
63 lines
1.9 KiB
C++
63 lines
1.9 KiB
C++
/* SPDX-License-Identifier: Apache-2.0
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* Copyright 2011-2022 Blender Foundation */
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#ifndef __UTIL_MATH_CDF_H__
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#define __UTIL_MATH_CDF_H__
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#include "util/algorithm.h"
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#include "util/math.h"
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#include "util/vector.h"
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CCL_NAMESPACE_BEGIN
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/* Evaluate CDF of a given functor with given range and resolution. */
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template<typename Functor>
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void util_cdf_evaluate(
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const int resolution, const float from, const float to, Functor functor, vector<float> &cdf)
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{
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const int cdf_count = resolution + 1;
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const float range = to - from;
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cdf.resize(cdf_count);
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cdf[0] = 0.0f;
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/* Actual CDF evaluation. */
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for (int i = 0; i < resolution; ++i) {
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float x = from + range * (float)i / (resolution - 1);
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float y = functor(x);
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cdf[i + 1] = cdf[i] + fabsf(y);
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}
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/* Normalize the CDF. */
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for (int i = 0; i <= resolution; i++) {
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cdf[i] /= cdf[resolution];
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}
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}
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/* Invert pre-calculated CDF function. */
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void util_cdf_invert(const int resolution,
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const float from,
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const float to,
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const vector<float> &cdf,
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const bool make_symmetric,
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vector<float> &inv_cdf);
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/* Evaluate inverted CDF of a given functor with given range and resolution. */
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template<typename Functor>
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void util_cdf_inverted(const int resolution,
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const float from,
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const float to,
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Functor functor,
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const bool make_symmetric,
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vector<float> &inv_cdf)
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{
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vector<float> cdf;
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/* There is no much smartness going around lower resolution for the CDF table,
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* this just to match the old code from pixel filter so it all stays exactly
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* the same and no regression tests are failed.
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*/
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util_cdf_evaluate(resolution - 1, from, to, functor, cdf);
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util_cdf_invert(resolution, from, to, cdf, make_symmetric, inv_cdf);
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}
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CCL_NAMESPACE_END
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#endif /* __UTIL_MATH_H_CDF__ */
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