vectomath: if start and end point are the same and equal the interpolated...

vectomath: if start and end point are the same and equal the interpolated point just return the according value

VectoCommon/VectoCommon/Utils/VectoMath.cs

@@ -134,6 +134,9 @@ namespace TUGraz.VectoCommon.Utils
 		[MethodImpl(MethodImplOptions.AggressiveInlining)]
 		public static double Interpolate(double x1, double x2, double y1, double y2, double xint)
 		{
+			if ((x1 - x2).IsEqual(0, 1e-9) && (x1 - xint).IsEqual(0, 1e-9)) {
+				return y1;
+			}
 			return (xint - x1) * (y2 - y1) / (x2 - x1) + y1;
 		}