# nim c --threads:on test_par_simple.nim

### defs
proc sizeUT(dim: int): int =
    return (dim * (dim+1) / 2).int

proc indexUT(i: int, j: int): int =
    return i + (j * (j+1) / 2).int

iterator iterUTindex(dim: int): tuple[i: int, j: int, ij: int] =
    var
        i: int = 0
        j: int = 0
        ij: int = 0
    while ij < sizeUT(dim):
        yield (i, j, ij)
        inc(ij)
        if i < j:
            inc(i)
        else:
            i = 0
            inc(j)

proc ijval(i: int, j: int): float =
    (i * j).float

### RUN
import threadpool

const
    dim: int = 100
    i: int = 3
    j: int = 4

var
    UT: seq[float] = newSeq[float](sizeUT(dim))

## set UT values
{.experimental.}
parallel:
    for index in iterUTindex(dim):
        if(index.ij <= UT.high): # artificial hint for OK bound check
            UT[index.ij] = spawn ijval(index.i,index.j) # TODO hint for index.ij disjoint check

## print result
echo UT[indexUT(i,j)]