public void CreateInterpolator_ReturnsFunctionWhichEvaluatesToInputs()
{
var xCoords = new[] { 1.2, 1.8, 2.5, 8.65 };
var yCoords = new[] { 46.56, -1.58, 8.556, 12.65 };
var interpolatorFactor = new NaturalCubicSplineInterpolatorFactory();
Func <double, double> interpolator = interpolatorFactor.CreateInterpolator(xCoords, yCoords);
for (int i = 0; i < xCoords.Length; i++)
{
double x = xCoords[i];
double y = interpolator(x);
double expectedY = yCoords[i];
Assert.Equal(expectedY, y, 12);
}
}
public void CreateInterpolator_FlatInputs_ReturnsFunctionWhichEvaluatesToConstantYValue()
{
const double constantY = 15.85;
var xCoords = new[] { 1.2, 1.8, 2.5, 8.65 };
var yCoords = new[] { constantY, constantY, constantY, constantY };
var interpolatorFactor = new NaturalCubicSplineInterpolatorFactory();
Func <double, double> interpolator = interpolatorFactor.CreateInterpolator(xCoords, yCoords);
var xsToEvaluate = new[] { 1.36, 2.15, 5.68, 7.99 };
foreach (double x in xsToEvaluate)
{
double y = interpolator(x);
Assert.Equal(constantY, y);
}
}