/// <summary>
/// Samples the input stream and applies a high-pass filter (using MathNet.Filtering) over the sampled input stream. Removes low frequencies.
/// </summary>
/// <param name="input">The input source of doubles.</param>
/// <param name="sampleRate">The desired sample rate for the filter.</param>
/// <param name="cutoffRate">The desired cutoff for the filter.</param>
/// <param name="impulseResponse">Specifies how the filter will respond to an impulse input (Finite or Infinite). Default is Finite.</param>
/// <param name="sampleInterpolator">Optional sampling interpolator over the input. Default is a reproducible linear interpolation.</param>
/// <param name="alignmentDateTime">If non-null, this parameter specifies a time to align the sampled messages with, and the sampled messages
/// will have originating times that align with (i.e., are an integral number of intervals away from) the specified alignment time.</param>
/// <param name="deliveryPolicy">An optional delivery policy for the input stream.</param>
/// <returns>A high-pass filtered version of the input.</returns>
public static IProducer <double> HighpassFilter(
this IProducer <double> input,
double sampleRate,
double cutoffRate,
ImpulseResponse impulseResponse = ImpulseResponse.Finite,
Interpolator <double, double> sampleInterpolator = null,
DateTime?alignmentDateTime = null,
DeliveryPolicy <double> deliveryPolicy = null)
{
var filter = OnlineFilter.CreateHighpass(impulseResponse, sampleRate, cutoffRate);
return(MathNetFilter(input, sampleRate, sampleInterpolator ?? Reproducible.Linear(), alignmentDateTime, filter, deliveryPolicy));
}
public void LinearInterpolate()
{
var evenres = new List <(double, DateTime)>();
var oddres = new List <(double, DateTime)>();
var results = new List <double>();
using (var p = Pipeline.Create())
{
var source = Generators.Sequence(p, 0, i => i + 1, 10, TimeSpan.FromTicks(50));
var even = source.Where(i => i % 2 == 0).Select(v => (double)v).Do((m, e) => evenres.Add((m, e.OriginatingTime)));
var odd = source.Where(i => i % 2 == 1).Select(v => (double)v).Do((m, e) => oddres.Add((m, e.OriginatingTime)));
even
.Interpolate(odd, Reproducible.Linear())
.Do(results.Add);
p.Run();
}
Assert.AreEqual(results.Count, 4);
Assert.AreEqual(results[0], 1, 0.00000001);
Assert.AreEqual(results[1], 3, 0.00000001);
Assert.AreEqual(results[2], 5, 0.00000001);
Assert.AreEqual(results[3], 7, 0.00000001);
}