Can I use a line object in a parallel.foreach loop?

Anonymous — Tue, 07 Apr 2020 14:00:01 GMT

I have a list of line objects stored in RAM and I want to see if any of them (one always will be) are parallel to a seperate line object which is also already on RAM so I don't have to read them from the database. I also have another line object that will cross the parallel line from the list but start at the beginning of the separate line and end at the opposite side of the line from the list as shown in the image below. List line is red and the two comparisons lines are green.

it will add the line that is parallel but only when its partner intersects to a concurrentbag. The problem I get is that it either does not find a value or it finds a value and repeats that line 162 times (the amount of lines I have in the list). It is random if does or does not find a result. I tied using a regular loop and it has the same problem. Not sure where I am going wrong.

using System; using System.Collections.Generic; using System.Threading.Tasks; using System.Windows.Forms; using System.Collections.Concurrent; using Autodesk.AutoCAD.ApplicationServices; using Autodesk.AutoCAD.DatabaseServices; using Autodesk.AutoCAD.EditorInput; namespace placePillars.Place_Cables { class CableIntersects { public static (Line, ObjectId) IntersectingCables(Document doc, Editor ed, Database db, List<Line> lineList, Line innerLine, Line outerLine) { //Assume the line is correct, ie y2-y bool innerbackwars = false; bool outerbackwars = false; bool linebackwards = false; Double mBoundary; Double bBoundary; Double mInner; Double mOuter; double tolerance = 0.01; ConcurrentBag<Line> newCable = new ConcurrentBag<Line>(); ObjectId cableIntersect = new ObjectId(); Line newcableResult = new Line(); //Check where the start point is in regards to the end point if (innerLine.EndPoint.X - innerLine.StartPoint.X < 0) { //start point is after end point innerbackwars = true; } if (outerLine.EndPoint.X - outerLine.StartPoint.X < 0) { outerbackwars = true; } //Workout gradient of unchanging lines if (innerbackwars == false) { mInner = (innerLine.EndPoint.Y - innerLine.StartPoint.Y) / (innerLine.EndPoint.X - innerLine.StartPoint.X); } else { mInner = (innerLine.StartPoint.Y - innerLine.EndPoint.Y) / (innerLine.StartPoint.X - innerLine.EndPoint.X);; } if (outerbackwars == false) { mOuter = (outerLine.EndPoint.Y - outerLine.StartPoint.Y) / (outerLine.EndPoint.X - outerLine.StartPoint.X); } else { mOuter = (outerLine.StartPoint.Y - outerLine.EndPoint.Y) / (outerLine.StartPoint.X - outerLine.EndPoint.X); } //Workout y axis intersect (where x=0) Double bInner = innerLine.StartPoint.Y - mInner * innerLine.StartPoint.X; Double bOuter = outerLine.StartPoint.Y - mOuter * outerLine.StartPoint.X; try { //using (DocumentLock acLckDoc = doc.LockDocument()) //{ //using (Transaction acTrans = db.TransactionManager.StartTransaction()) //{ //Check for parallel lines first //Parallel.ForEach(lineList, (lineRecord) => foreach(Line lineRecord in lineList) { bool inner = false; bool outer = false; if (lineRecord.EndPoint.X - lineRecord.StartPoint.X < 0) { //start point is after end point linebackwards = true; } //Workout gradients of the lines if (linebackwards == false) { mBoundary = (lineRecord.EndPoint.Y - lineRecord.StartPoint.Y) / (lineRecord.EndPoint.X - lineRecord.StartPoint.X); } else { mBoundary = (lineRecord.StartPoint.Y - lineRecord.EndPoint.Y) / (lineRecord.StartPoint.X - lineRecord.EndPoint.X); } bBoundary = lineRecord.StartPoint.Y - mBoundary * lineRecord.StartPoint.X; //test to see if innter out outer intersect //Check to see if they are parallel to reduce calculations //y=xm+b ---> xm+b=y=xm+b ---> x=x (move x to LHS) ---> x+x(-1) var x = mBoundary + mInner * -1; var b = bBoundary * -1 + bInner; if (x <= tolerance && x >= -tolerance) x = 0; double x1 = (float)b / (float)x; x = mBoundary + mOuter * -1; b = bBoundary * -1 + bOuter; if (x <= tolerance && x >= -tolerance) x = 0; double x2 = (float)b / (float)x; var _y = lineRecord.Handle.Value; if (_y==67397683) { var _u = 1; } //If X1 is the intercept line then we want to look at ir whilst X2 = inf if (!double.IsInfinity(x1) && double.IsInfinity(x2)) { //Dont know if line start or end comes first on x axis so work it out based on line length from x=0 if (innerbackwars == true) { if (x1 < innerLine.StartPoint.X && x1 > innerLine.EndPoint.X) { //if inner line intercepts then we want the outer as our cable outer = true; } } if (innerbackwars == false) { if (x1 > innerLine.StartPoint.X && x1 < innerLine.EndPoint.X) { outer = true; } } //if (inner == true && outer == false) break; } //Now see if outer cable intersects if (double.IsInfinity(x1) && !double.IsInfinity(x2)) { //Dont know if line start or end comes first on x axis so work it out based on line length from x=0 if (outerbackwars == false) { if (x2 < outerLine.StartPoint.X && x2 > outerLine.EndPoint.X) { inner = true; } } if (outerbackwars == true) { if (x2 > outerLine.StartPoint.X && x2 < outerLine.EndPoint.X) { inner = true; } } } if ((inner == true && outer == false) || (inner == false && outer == true)) { if (inner == true) { newCable.Add(innerLine); cableIntersect = outerLine.ObjectId; inner = false; outer = false; } else { newCable.Add(outerLine); cableIntersect = innerLine.ObjectId; inner = false; outer = false; } } }//);//End of loop //} //} var newcacleCount = newCable.Count; if (newcacleCount == 0) { var _a = 1; } //if (newcacleCount > 1) { } else { foreach(var item in newCable) { newcableResult = item; } }; } catch (System.Exception ex) { MessageBox.Show(ex.StackTrace); MessageBox.Show(ex.Source); } return (newcableResult, cableIntersect) ; } } }

Re: Can I use a line object in a parallel.foreach loop?

_gile — Tue, 07 Apr 2020 14:18:38 GMT

Hi,

AFAIK, you cannot use parallel computing with DBObjects, but it may be possible with some non-database resident geometric objects (I know it is possible with Point3d, I did it here).

You could try with LineSegment3d objects instead of Lines

Re: Can I use a line object in a parallel.foreach loop?

Anonymous — Wed, 08 Apr 2020 10:36:58 GMT

Thanks Gile, I will have to change the Line object out. I assume i can just copy the x,y coordinates to a float if the 3Dpoint doesn't workout

Re: Can I use a line object in a parallel.foreach loop?

ActivistInvestor — Thu, 09 Apr 2020 03:54:54 GMT

Regarding this snippet from your code:

if ((inner == true && outer == false) || (inner == false && outer == true))

Is equivalent to:

if (inner ^ outer)

the ^ (exclusive or) operator returns true if one of its operands is true and the other is false.

Re: Can I use a line object in a parallel.foreach loop?

Anonymous — Thu, 09 Apr 2020 11:12:13 GMT

Thank you, I will change that. Would reduce processing needed at all?

Re: Can I use a line object in a parallel.foreach loop?

ActivistInvestor — Fri, 10 Apr 2020 14:22:48 GMT

Yes reducing it to a single simple operation would be more efficient.

Also, comparing a Boolean value to True is redundant.

if(x == true)

Is equivalent to

if(x)

And

if(x == false)

Is equivalent to

if(!x)

Re: Can I use a line object in a parallel.foreach loop?

Anonymous — Sat, 11 Apr 2020 10:30:27 GMT

Thanks, I didnt even think about this but when you mentioned it I thought that might be referring to efficiency. I guess I have to treat higher languages like a microcontroller

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Can I use a line object in a parallel.foreach loop?

Re: Can I use a line object in a parallel.foreach loop?

Re: Can I use a line object in a parallel.foreach loop?

Re: Can I use a line object in a parallel.foreach loop?

Re: Can I use a line object in a parallel.foreach loop?

Re: Can I use a line object in a parallel.foreach loop?

Re: Can I use a line object in a parallel.foreach loop?