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rewired some functions in qmc.h for better convenience

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Wenzel Jakob 2014-01-02 01:31:41 +01:00
parent ea3d61da15
commit 567b368fa6
1 changed files with 38 additions and 29 deletions
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65
include/mitsuba/core/qmc.h
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@ -155,7 +155,6 @@ inline uint64_t sampleTEA(uint32_t v0, uint32_t v1, int rounds = 4) {
return ((uint64_t) v1 << 32) + v0; return ((uint64_t) v1 << 32) + v0;
} }
#if defined(DOUBLE_PRECISION)
/** /**
* \brief Generate fast and reasonably good pseudorandom numbers using the * \brief Generate fast and reasonably good pseudorandom numbers using the
* Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham. * Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham.
@ -173,7 +172,35 @@ inline uint64_t sampleTEA(uint32_t v0, uint32_t v1, int rounds = 4) {
* \return * \return
* A uniformly distributed floating point number on the interval <tt>[0, 1)</tt> * A uniformly distributed floating point number on the interval <tt>[0, 1)</tt>
*/ */
inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) { inline float sampleTEASingle(uint32_t v0, uint32_t v1, int rounds = 4) {
/* Trick from MTGP: generate an uniformly distributed
single precision number in [1,2) and subtract 1. */
union {
uint32_t u;
float f;
} x;
x.u = ((sampleTEA(v0, v1, rounds) & 0xFFFFFFFF) >> 9) | 0x3f800000UL;
return x.f - 1.0f;
}
/**
* \brief Generate fast and reasonably good pseudorandom numbers using the
* Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham.
*
* This function uses \ref sampleTEA to return single precision floating point
* numbers on the interval <tt>[0, 1)</tt>
*
* \param v0
* First input value to be encrypted (could be the sample index)
* \param v1
* Second input value to be encrypted (e.g. the requested random number dimension)
* \param rounds
* How many rounds should be executed? The default for random number
* generation is 4.
* \return
* A uniformly distributed floating point number on the interval <tt>[0, 1)</tt>
*/
inline double sampleTEADouble(uint32_t v0, uint32_t v1, int rounds = 4) {
/* Trick from MTGP: generate an uniformly distributed /* Trick from MTGP: generate an uniformly distributed
single precision number in [1,2) and subtract 1. */ single precision number in [1,2) and subtract 1. */
union { union {
@ -184,33 +211,15 @@ inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) {
return x.f - 1.0; return x.f - 1.0;
} }
#else #if defined(SINGLE_PRECISION)
/** /// Alias to \ref sampleTEASingle or \ref sampleTEADouble based on compilation flags
* \brief Generate fast and reasonably good pseudorandom numbers using the
* Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham.
*
* This function uses \ref sampleTEA to return single precision floating point
* numbers on the interval <tt>[0, 1)</tt>
*
* \param v0
* First input value to be encrypted (could be the sample index)
* \param v1
* Second input value to be encrypted (e.g. the requested random number dimension)
* \param rounds
* How many rounds should be executed? The default for random number
* generation is 4.
* \return
* A uniformly distributed floating point number on the interval <tt>[0, 1)</tt>
*/
inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) { inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) {
/* Trick from MTGP: generate an uniformly distributed return sampleTEASingle(v0, v1, rounds);
single precision number in [1,2) and subtract 1. */ }
union { #else
uint32_t u; /// Alias to \ref sampleTEASingle or \ref sampleTEADouble based on compilation flags
float f; inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) {
} x; return sampleTEADouble(v0, v1, rounds);
x.u = ((sampleTEA(v0, v1, rounds) & 0xFFFFFFFF) >> 9) | 0x3f800000UL;
return x.f - 1.0f;
} }
#endif #endif