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34 lines
1.1 KiB
Nim
34 lines
1.1 KiB
Nim
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import
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std/[strutils, math, cpuinfo],
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taskpools
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# From https://github.com/nim-lang/Nim/blob/v1.6.2/tests/parallel/tpi.nim
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# Leibniz Formula https://en.wikipedia.org/wiki/Leibniz_formula_for_%CF%80
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proc term(k: int): float =
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if k mod 2 == 1:
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-4'f / float(2*k + 1)
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else:
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4'f / float(2*k + 1)
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proc piApprox(tp: Taskpool, n: int): float =
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var pendingFuts = newSeq[FlowVar[float]](n)
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for k in 0 ..< pendingFuts.len:
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pendingFuts[k] = tp.spawn term(k) # Schedule a task on the threadpool a return a handle to retrieve the result.
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for k in 0 ..< pendingFuts.len:
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result += sync pendingFuts[k] # Block until the result is available.
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proc main() =
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var n = 1_000_000
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var nthreads = countProcessors()
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var tp = Taskpool.new(num_threads = nthreads) # Default to the number of hardware threads.
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echo formatFloat(tp.piApprox(n))
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tp.syncAll() # Block until all pending tasks are processed (implied in tp.shutdown())
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tp.shutdown()
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# Compile with nim c -r -d:release --threads:on --outdir:build example.nim
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main() |