Brecht Van Lommel
fd25e883e2
Remove prefix of filenames that is the same as the folder name. This used to help when #includes were using individual files, but now they are always relative to the cycles root directory and so the prefixes are redundant. For patches and branches, git merge and rebase should be able to detect the renames and move over code to the right file.
95 lines
3.2 KiB
C++
95 lines
3.2 KiB
C++
/*
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* Sobol sequence direction vectors.
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*
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* This file contains code to create direction vectors for generating sobol
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* sequences in high dimensions. It is adapted from code on this webpage:
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*
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* http://web.maths.unsw.edu.au/~fkuo/sobol/
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*
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* From these papers:
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*
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* S. Joe and F. Y. Kuo, Remark on Algorithm 659: Implementing Sobol's quasirandom
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* sequence generator, ACM Trans. Math. Softw. 29, 49-57 (2003)
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*
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* S. Joe and F. Y. Kuo, Constructing Sobol sequences with better two-dimensional
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* projections, SIAM J. Sci. Comput. 30, 2635-2654 (2008)
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*/
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/* Copyright (c) 2008, Frances Y. Kuo and Stephen Joe
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* * Neither the names of the copyright holders nor the names of the
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* University of New South Wales and the University of Waikato
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* and its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "util/types.h"
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#include "scene/sobol.h"
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CCL_NAMESPACE_BEGIN
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#include "scene/sobol.tables"
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void sobol_generate_direction_vectors(uint vectors[][SOBOL_BITS], int dimensions)
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{
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assert(dimensions <= SOBOL_MAX_DIMENSIONS);
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const uint L = SOBOL_BITS;
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/* first dimension is exception */
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uint *v = vectors[0];
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for (uint i = 0; i < L; i++)
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v[i] = 1 << (31 - i); // all m's = 1
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for (int dim = 1; dim < dimensions; dim++) {
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const SobolDirectionNumbers *numbers = &SOBOL_NUMBERS[dim - 1];
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const uint s = numbers->s;
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const uint a = numbers->a;
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const uint *m = numbers->m;
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v = vectors[dim];
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if (L <= s) {
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for (uint i = 0; i < L; i++)
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v[i] = m[i] << (31 - i);
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}
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else {
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for (uint i = 0; i < s; i++)
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v[i] = m[i] << (31 - i);
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for (uint i = s; i < L; i++) {
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v[i] = v[i - s] ^ (v[i - s] >> s);
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for (uint k = 1; k < s; k++)
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v[i] ^= (((a >> (s - 1 - k)) & 1) * v[i - k]);
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}
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}
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}
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}
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CCL_NAMESPACE_END
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