1  
 2  import std/[strutils, math, cpuinfo]
 3  
 4  import taskpools
 5  
 6  # From https://github.com/nim-lang/Nim/blob/v1.6.2/tests/parallel/tpi.nim
 7  # Leibniz Formula https://en.wikipedia.org/wiki/Leibniz_formula_for_%CF%80
 8  proc term(k: int): float =
 9    if k mod 2 == 1:
10      -4'f / float(2*k + 1)
11    else:
12      4'f / float(2*k + 1)
13  
14  proc piApprox(tp: Taskpool, n: int): float =
15    var pendingFuts = newSeq[FlowVar[float]](n)
16    for k in 0 ..< pendingFuts.len:
17      pendingFuts[k] = tp.spawn term(k) # Schedule a task on the threadpool a return a handle to retrieve the result.
18    for k in 0 ..< pendingFuts.len:
19      result += sync pendingFuts[k]     # Block until the result is available.
20  
21  proc main() =
22    var n = 1_000
23    var nthreads = countProcessors()
24  
25    var tp = Taskpool.new(num_threads = nthreads) # Default to the number of hardware threads.
26  
27    echo formatFloat(tp.piApprox(n))
28  
29    tp.syncAll()                                  # Block until all pending tasks are processed (implied in tp.shutdown())
30    tp.shutdown()
31  
32  # Compile with nim c -r -d:release --threads:on --outdir:build example.nim
33  main()
34  
35  when false:
36    type
37      ScratchObj_486539477 = object
38        k: int
39        fut: Flowvar[float]
40  
41    let scratch_486539455 = cast[ptr ScratchObj_486539477](c_calloc(csize_t 1,
42        csize_t sizeof(ScratchObj_486539477)))
43    if scratch_486539455.isNil:
44      raise newException(OutOfMemDefect, "Could not allocate memory")
45    block:
46      var isoTemp_486539473 = isolate(k)
47      scratch_486539455.k = extract(isoTemp_486539473)
48      var isoTemp_486539475 = isolate(fut)
49      scratch_486539455.fut = extract(isoTemp_486539475)
50    proc taskpool_term_486539478(args: pointer) {.gcsafe, nimcall,
51        raises: [].} =
52      let objTemp_486539472 = cast[ptr ScratchObj_486539477](args)
53      let k_486539474 = objTemp_486539472.k
54      let fut_486539476 = objTemp_486539472.fut
55      taskpool_term(k = k_486539474, fut = fut_486539476)
56  
57    proc destroyScratch_486539479(args: pointer) {.gcsafe, nimcall,
58        raises: [].} =
59      let obj_486539480 = cast[ptr ScratchObj_486539477](args)
60      `=destroy`(obj_486539480[])
61  
62    Task(callback: taskpool_term_486539478, args: scratch_486539455,
63        destroy: destroyScratch_486539479)