How to convert Parallel.For to PLINQ

Question

Parallel.For(0, Height, new ParallelOptions { MaxDegreeOfParallelism = 6 }, y =>
{
    int currentLine = y * BMPData.Stride;

    for (int x = 0; x < Width; x = x + BPX)
    {
        var b = pixels[currentLine + x];
        var g = pixels[currentLine + x + 1];
        var r = pixels[currentLine + x + 2];

        int avg = (r + g + b) / 3;
        pixels[currentLine + x] = (byte)avg;
        pixels[currentLine + x + 1] = (byte)avg;
        pixels[currentLine + x + 2] = (byte)avg;
    }
});

This is basically a parallel code where it turns bitmap data pixels into gray ones, but is there any way I can replace the Parallel.For usage with Parallel Linq? I know there's no point to this, but it's required for a certain assignment

Answer 1

You can use Enumerable.Range, and ForAll to get similar results. Although note ForAll will not process the list in any stable order - which is probably fine for your use case

Enumerable.Range(0,Height)
          .AsParallel()
          .WithDegreeOfParallelism(6)
          .ForAll(y => 
{
   /// existing code here
});