/// <summary>
/// Tests if a point is inside the circle defined by
/// the triangle with vertices a, b, c (oriented counter-clockwise).
/// </summary>
/// <remarks>
/// The computation uses <see cref="DD"/> arithmetic for robustness, but a faster approach.
/// </remarks>
/// <param name="a">A vertex of the triangle</param>
/// <param name="b">A vertex of the triangle</param>
/// <param name="c">A vertex of the triangle</param>
/// <param name="p">The point to test</param>
/// <returns>true if this point is inside the circle defined by the points a, b, c</returns>
public static bool IsInCircleDDFast(
Coordinate a, Coordinate b, Coordinate c,
Coordinate p)
{
var aTerm = (DD.Sqr(a.X) + DD.Sqr(a.Y)) * TriAreaDDFast(b, c, p);
var bTerm = (DD.Sqr(b.X) + DD.Sqr(b.Y)) * TriAreaDDFast(a, c, p);
var cTerm = (DD.Sqr(c.X) + DD.Sqr(c.Y)) * TriAreaDDFast(a, b, p);
var pTerm = (DD.Sqr(p.X) + DD.Sqr(p.Y)) * TriAreaDDFast(a, b, c);
var sum = aTerm - bTerm + cTerm - pTerm;
bool isInCircle = sum.ToDoubleValue() > 0;
return(isInCircle);
}
/// <summary>
/// Tests if a point is inside the circle defined by the points a, b, c.
/// The computation uses <see cref="NetTopologySuite.Mathematics.DD"/> arithmetic for robustness.
/// </summary>
/// <param name="a">A vertex of the triangle</param>
/// <param name="b">A vertex of the triangle</param>
/// <param name="c">A vertex of the triangle</param>
/// <param name="p">The point to test</param>
/// <returns><value>true</value> if this point is inside the circle defined by the points a, b, c</returns>
public static bool IsInCircleDD2(
Coordinate a, Coordinate b, Coordinate c,
Coordinate p)
{
DD aTerm = (DD.Sqr(a.X) + DD.Sqr(a.Y)) * TriAreaDD2(b, c, p);
DD bTerm = (DD.Sqr(b.X) + DD.Sqr(b.Y)) * TriAreaDD2(a, c, p);
DD cTerm = (DD.Sqr(c.X) + DD.Sqr(c.Y)) * TriAreaDD2(a, b, p);
DD pTerm = (DD.Sqr(p.X) + DD.Sqr(p.Y)) * TriAreaDD2(a, b, c);
DD sum = aTerm - bTerm + cTerm - pTerm;
var isInCircle = sum.ToDoubleValue() > 0;
return(isInCircle);
}
/// <summary>
/// This routine simply tests for robustness of the toString function.
/// </summary>
static void WriteRepeatedSqr(DD xdd)
{
if (xdd.GreaterOrEqualThan(DD.ValueOf(1)))
{
throw new ArgumentException("Argument must be < 1");
}
int count = 0;
while (xdd.ToDoubleValue() > 1e-300)
{
count++;
double x = xdd.ToDoubleValue();
var xSqr = xdd.Sqr();
string s = xSqr.ToString();
// System.Console.WriteLine(count + ": " + s);
var xSqr2 = DD.Parse(s);
xdd = xSqr;
}
}
/**
* This routine simply tests for robustness of the toString function.
*
* @param xdd
*/
static void WriteRepeatedSqr(DD xdd)
{
if (xdd.GreaterOrEqualThan(DD.ValueOf(1)))
throw new ArgumentException("Argument must be < 1");
int count = 0;
while (xdd.ToDoubleValue() > 1e-300) {
count++;
double x = xdd.ToDoubleValue();
DD xSqr = xdd.Sqr();
String s = xSqr.ToString();
Console.WriteLine(count + ": " + s);
DD xSqr2 = DD.Parse(s);
xdd = xSqr;
}
}
