Subtractive generator: Difference between revisions

=={{header|Julia}}==

Here is a script, which does not use multiplicative operators, without relying on the optimizer.

{{works with|Julia|1.0}}

<lang julia>i,j,m,d,seed = 55,24,10^9,34,292929 # parameters

s = Array{Int32}(undef,i); r = similar(s)

s[1:2] = [seed,1] # table initialization

for n = 3:i; (s[n] = s[n-2]-s[n-1]) < 0 && (s[n] += m) end

t = 1; for u=1:i; (global t+=d)>i && (t-=i); r[u]=s[t] end # permutation, r = s[(d*(1:i) .% i).+1]

u,v,n = i,i-j,i-1

while (n += 1) > 0

(global u += 1) > i && (u = 1) # circular indexing: u,v = ((n,n-j) .% i).+1

(global v += 1) > i && (v = 1)

(r[u] -= r[v]) < 0 && (r[u] += m) # table update

n < 220 && continue # 165 silent values

print((n,r[u])) # show (index,value) of next pseudorandom number

x = readline(stdin) # wait until the ENTER key is pressed

length(x) > 0 && break # any other key before ENTER => exit

end</lang>

{{out}}

<pre>(220, 467478574)

(221, 512932792)

(222, 539453717)

(223, 20349702)

(224, 615542081)

(225, 378707948)

(226, 933204586)

(227, 824858649)

(228, 506003769)

(229, 380969305)

(230, 442823364)

(231, 994162810)

(232, 261423281)</pre>