add mixture implementation in nim.

This commit is contained in:
NunoSempere 2023-05-21 00:46:10 -04:00
parent ccdeb77f3f
commit 76968afc79
3 changed files with 43 additions and 5 deletions

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@ -1,2 +1,2 @@
build: samples.nim
nim c samples.nim
nim c --verbosity:0 samples.nim

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import std/math
import std/sugar
import std/random
import std/sequtils
randomize()
@ -84,7 +86,43 @@ proc to(low: float, high: float): float =
let logsigma = (loghigh - loglow) / (2.0 * normal95confidencePoint);
return lognormal(logmean, logsigma)
echo ur_normal()
echo normal(10, 20)
echo lognormal(2, 4)
echo to(10, 90)
## echo ur_normal()
## echo normal(10, 20)
## echo lognormal(2, 4)
## echo to(10, 90)
## Manipulate samples
proc make_samples(f: () -> float, n: int): seq[float] =
result = toSeq(1..n).map(_ => f())
return result
proc mixture(sxs: seq[seq[float]], ps: seq[float], n: int): seq[float] =
assert sxs.len == ps.len
var ws: seq[float]
var sum = 0.0
for i, p in ps:
sum = sum + p
ws.add(sum)
ws = ws.map(w => w/sum)
proc get_mixture_sample(): float =
let r = rand(1.0)
var i = ws.len - 1
for j, w in ws:
if r < w:
i = j
break
## only occasion when ^ doesn't assign i
## is when r is exactly 1
## which would correspond to choosing the last item in ws
## which is why i is initialized to ws.len
let xs = sxs[i]
let l = xs.len-1
let k = rand(0..l)
return xs[k]
return toSeq(1..n).map(_ => get_mixture_sample())