Parallel.For in C# component crash Rhino.

Hi,

I would like to use Parallel.For for this simple loop:

private void RunScript(List<Guid> guid, List<Plane> plane, Box box)
{

for(int i = 0; i < plane.Count; i++){
Rhino.Render.TextureMapping textureMapping = Rhino.Render.TextureMapping.CreateBoxMapping(plane[i], box.X, box.Y, box.Z, true);
Rhino.RhinoDoc.ActiveDoc.Objects.ModifyTextureMapping(guid[i], 1, textureMapping);
}

}

I tried this one, but it crashes rhino immediately.

Honestly I am new to multi-threading, can somebody tell why crash occurs and how to properly use Parallel.For in this case? Thank you :)

private void RunScript(List<Guid> guid, List<Plane> plane, Box box)
{

System.Threading.Tasks.Parallel.For(0, plane.Count, i => {
Rhino.Render.TextureMapping textureMapping = Rhino.Render.TextureMapping.CreateBoxMapping(plane[i], box.X, box.Y, box.Z, true);
Rhino.RhinoDoc.ActiveDoc.Objects.ModifyTextureMapping(guid[i], 1, textureMapping);
});
}

Replies to This Discussion

Permalink Reply by 0ddw589ypu3jv on May 20, 2017 at 1:05pm

Try this

private void RunScript(List guid, List plane, Box box)

{

var numbers = Enumerable.Range(0, plane.Count);
var result = numbers.AsParallel().AsOrdered();

foreach (var i in result)
{

Rhino.Render.TextureMapping textureMapping = Rhino.Render.TextureMapping.CreateBoxMapping(plane[i], box.X, box.Y, box.Z, true);

Rhino.RhinoDoc.ActiveDoc.Objects.ModifyTextureMapping(guid[i], 1, textureMapping);

}

Permalink Reply by John on May 20, 2017 at 2:17pm

Thanks, Could you explain what is happening here:

var result = numbers.AsParallel().AsOrdered();

And why foreach instead of Parallel.foreach?

Permalink Reply by 0ddw589ypu3jv on May 20, 2017 at 3:44pm

Parallel.ForEach will block until all tasks are completed or the tasks are cancelled.

I think the method ModifyTextureMapping canot be cancled.so it will block until the task is completed

Permalink Reply by John on May 20, 2017 at 3:59pm

Could you give any good reference about multi-threading in general?

Permalink Reply by peter fotiadis on May 21, 2017 at 12:32am

Master talks // stuff (BTW: // is not the Jack for all trades as most people believe):

http://www.albahari.com/threading/

Permalink Reply by peter fotiadis on May 21, 2017 at 1:51am

BTW: Use some big numbers and have fun with this

Attachments:

Apply_at_KGB_V1.gh, 131 KB

Permalink Reply by peter fotiadis on May 21, 2017 at 9:45am

Forgot to mention this as well:

https://www.packtpub.com/application-development/multithreading-c-c...

Permalink Reply by Matthew Breau on May 22, 2017 at 10:58am

This is a great reference:

http://james-ramsden.com/multithreading-a-foreach-loop-in-a-grassho...

Permalink Reply by peter fotiadis on May 23, 2017 at 12:59am

This has a "minor" syntax error (it would never work).

Try the attached.

BTW: Some day may I post a combo of ~50 // "real-life" cases that prove that things are not that easy ... especially in AEC because the time required to figure out a proper scheduler denies - in most of cases - the benefits. Kinda like the catalysts in fuel injected engines (target missed my some miles from day zero).

Attachments: