simdjson/benchmark/genfeaturejsonseed.rb

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def gen_seeds(start_blocks, repeat_blocks, end_blocks)
total_size = 640*1000
total_blocks = total_size/64
seed_space = 1..1000000
target_blocks = total_blocks*0.5
target_flips = total_blocks*0.25
percent_flips = 0.25*repeat_blocks
puts "Seeds for #{start_blocks} start blocks, #{end_blocks} end blocks and #{repeat_blocks} repeat blocks: #{percent_flips*100}% flips"
closest_flips = nil
closest_seeds = []
seed_space.each do |seed|
r = Random.new(seed)
# First block is always type 1
flips = 0
type1 = true
type1_blocks = start_blocks
finished_blocks = start_blocks
last_repeat = total_blocks-end_blocks
while finished_blocks < last_repeat
if r.rand < percent_flips
flips += 1
type1 = !type1
end
type1_blocks += repeat_blocks if type1
finished_blocks += repeat_blocks
end
# Last one is always type 1
flips += 1 if !type1
type1 = true
type1_blocks += end_blocks
finished_blocks += end_blocks
raise "simulated the wrong number of blocks #{finished_blocks}" if finished_blocks != total_blocks
if type1_blocks == target_blocks
if flips == target_flips
puts seed
closest_seeds << seed
end
end
end
puts closest_seeds
end
gen_seeds(1,1,1)
gen_seeds(1,1,2)
gen_seeds(2,2,4)