/// <summary>
/// Create a linear spline interpolation from an unsorted set of (x,y) value pairs.
/// WARNING: Works in-place and can thus causes the data array to be reordered and modified.
/// </summary>
public static TransformedInterpolation InterpolateInplace(
Func <double, double> transform,
Func <double, double> transformInverse,
double[] x,
double[] y)
{
if (x.Length != y.Length)
{
throw new ArgumentException("All vectors must have the same dimensionality.");
}
Sorting.Sort(x, y);
CommonParallel.For(0, y.Length, 4096, (a, b) =>
{
for (int i = a; i < b; i++)
{
y[i] = transformInverse(y[i]);
}
});
return(new TransformedInterpolation(LinearSpline.InterpolateSorted(x, y), transform));
}
/// <summary>
/// Create a linear spline interpolation from a set of (x,y) value pairs, sorted ascendingly by x.
/// </summary>
public static TransformedInterpolation InterpolateSorted(
Func <double, double> transform,
Func <double, double> transformInverse,
double[] x,
double[] y)
{
if (x.Length != y.Length)
{
throw new ArgumentException(Resource.ArgumentVectorsSameLength);
}
var yhat = new double[y.Length];
CommonParallel.For(0, y.Length, 4096, (a, b) =>
{
for (int i = a; i < b; i++)
{
yhat[i] = transformInverse(y[i]);
}
});
return(new TransformedInterpolation(LinearSpline.InterpolateSorted(x, yhat), transform));
}
/// <param name="x">Sample points (N), sorted ascending</param>
/// <param name="logy">Natural logarithm of the sample values (N) at the corresponding points</param>
public LogLinear(double[] x, double[] logy)
{
_spline = LinearSpline.InterpolateSorted(x, logy);
}