Module: ThreadSafe::Util::XorShiftRandom
- Extended by:
- XorShiftRandom
- Included in:
- XorShiftRandom
- Defined in:
- lib/thread_safe/util/xor_shift_random.rb
Overview
A xorshift random number (positive Fixnums) generator, provides reasonably cheap way to generate thread local random numbers without contending for the global Kernel.rand
. Usage:
x = XorShiftRandom.get # uses Kernel.rand to generate an initial seed
while true
if (x = XorShiftRandom.xorshift).odd? # thread-localy generate a next random number
do_something_at_random
end
end
Constant Summary collapse
- MAX_XOR_SHIFTABLE_INT =
MAX_INT - 1
Instance Method Summary collapse
-
#get ⇒ Object
Generates an initial non-zero positive
Fixnum
viaKernel.rand
. -
#xorshift(x) ⇒ Object
using the “yˆ=y>>a; yˆ=y<<b; yˆ=y>>c;” transform with the (a,b,c) tuple with values (1,1,54) to minimise Bignum overflows.
Instance Method Details
#get ⇒ Object
Generates an initial non-zero positive Fixnum
via Kernel.rand
.
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# File 'lib/thread_safe/util/xor_shift_random.rb', line 17 def get Kernel.rand(MAX_XOR_SHIFTABLE_INT) + 1 # 0 can't be xorshifted end |
#xorshift(x) ⇒ Object
using the “yˆ=y>>a; yˆ=y<<b; yˆ=y>>c;” transform with the (a,b,c) tuple with values (1,1,54) to minimise Bignum overflows
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# File 'lib/thread_safe/util/xor_shift_random.rb', line 24 def xorshift(x) x ^= x >> 3 x ^= (x << 1) & MAX_INT # cut-off Bignum overflow x ^= x >> 14 end |