Advanced Brachytherapy Physics - Vienna 2016

Type B uncertainty … random number generator

Pseudo random number generators are used, e.g. Lehmer type, multiplicative- congruential of the form: r =Br mod2 M n+1 n

with B,M and r 0

(the “seed” of the sequence) appropriately selected.

• These generators are generally robust in benchmarked and extensively used codes

• These generators are periodic with a period of 2 M . Exceeding this period might underestimate result variance

• If you are using different simulations to estimate Var(k) make sure the seed is d ffi erent