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@@ -28,17 +28,17 @@ |
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typedef struct { |
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unsigned int mt[AV_RANDOM_N]; ///< the array for the state vector |
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int index; ///< current untempered value we use as the base. |
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int index; ///< Current untempered value we use as the base. |
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} AVRandomState; |
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void av_init_random(unsigned int seed, AVRandomState *state); ///< to be inlined, the struct must be visible, so it doesn't make sense to try and keep it opaque with malloc/free like calls |
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void av_random_generate_untempered_numbers(AVRandomState *state); ///< Regenerate the untempered numbers (must be done every 624 iterations, or it will loop) |
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void av_init_random(unsigned int seed, AVRandomState *state); ///< To be inlined, the struct must be visible. So it does not make sense to try and keep it opaque with malloc/free-like calls. |
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void av_random_generate_untempered_numbers(AVRandomState *state); ///< Regenerate the untempered numbers (must be done every 624 iterations, or it will loop). |
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/** |
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* generates a random number on [0,0xffffffff]-interval |
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* Generates a random number from the interval [0,0xffffffff]. |
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* |
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* Please do NOT use the mersenne twister, it is slow, use the random generator |
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* Please do NOT use the Mersenne Twister, it is slow. Use the random generator |
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* from lfg.c/h or a simple LCG like state= state*1664525+1013904223. |
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* If you still choose to use MT, expect that you will have to provide |
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* some evidence that it makes a difference for the case where you use it. |
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@@ -47,14 +47,14 @@ static inline unsigned int av_random(AVRandomState *state) |
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{ |
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unsigned int y; |
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// regenerate the untempered numbers if we should... |
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// Regenerate the untempered numbers if we should... |
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if (state->index >= AV_RANDOM_N) |
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av_random_generate_untempered_numbers(state); |
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// grab one... |
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// Grab one... |
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y = state->mt[state->index++]; |
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/* Now temper (Mersenne Twister coefficients) The coefficients for MT19937 are.. */ |
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/* Now temper (Mersenne Twister coefficients). The coefficients for MT19937 are.. */ |
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y ^= (y >> 11); |
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y ^= (y << 7) & 0x9d2c5680; |
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y ^= (y << 15) & 0xefc60000; |
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@@ -63,7 +63,7 @@ static inline unsigned int av_random(AVRandomState *state) |
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return y; |
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} |
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/** return random in range [0-1] as double */ |
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/** Return random in range [0-1] as double. */ |
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static inline double av_random_real1(AVRandomState *state) |
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{ |
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/* divided by 2^32-1 */ |
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