Various Random Number Generators and the Applications Jeff Atkinson Hirophysics.com
The advantages of using random numbers To make complicated calculation simple To estimate the result efficiently To simulate nature’s randomness Hirophysics.com
How to find with random numbers Throw darts randomly to the target shown. Count how many darts placed within the circle. Calculate the percentage that gives the area of the circle. Divide it by r2 to obtain . r r Hirophysics.com
Case 1 The number of darts inside the shaded area = 6 The total number of darts = 8 The area of full circle = 46/8=3 If r=1, the above is also . Hirophysics.com
Case 2 The number of darts inside the shaded area = 12 The total number of darts = 17 The area of full circle = 412/17=2.824 If r=1, the above is also . Hirophysics.com
Case 3 The number of darts inside the shaded area = 47,000 The total number of darts = 60,000 The area of full circle = 447,000/60,000=3.1 3333 If r=1, the above is also . Hirophysics.com
Uniformly distributed random numbers Hirophysics.com
Box-Muller Distribution All data is centered around an average value and most data stays within a certain radius called the standard deviation (σ). To create a Box-Muller distribution, the following equations are applied to two uniformly distributed random numbers, U1 and U2: Hirophysics.com
Arcsine “Bucket” Distribution Most data comes together the upper and lower bounds. The numbers are from logistic map. Hirophysics.com
Computer simulation with 10,000 uniform random numbers The approximated = 3.1356000000000002 Hirophysics.com
with Box-Muller with different standard deviations STDV ---- 0.1 ---- 4.000 0.2 ---- 3.992 0.3 ---- 3.752 0.4 ---- 3.157 0.5 ---- 2.522 0.6 ---- 2.002 Hirophysics.com
Random Walk Mathematical determination of a path that is generated by a succession of random values. Simulation of Brownian motion and other natural random motions A formalism that are applied to other complex science and engineering Hirophysics.com
Random Walk with Uniform Random Number Eventual Average Distance = N Hirophysics.com
Random Walk with Box-Muller Eventual Average Distance = N Hirophysics.com
Random Walk with Arcsine Eventual Average Distance = 1.617N N --- Distance 500 --- 35.720 1500 --- 61.054 2500 --- 82.088 3500 --- 87.199 4500 --- 103.623 5500 --- 118.542 6500 --- 124.039 7500 --- 135.237 . 10,000 --- 162.129 Hirophysics.com
Conclusions For mathematical problems, such as , the data must be truly random and uniform. The Box-Muller distribution does not work to find because it depends on the standard deviation. The random walk with arcsine distribution with logistic map [yn+1=4.0yn(1-yn)] gives the eventual average distance as 1.617N computationally. Hirophysics.com