private void updateSeasonalAndTrend(bool useResidualWeights)
{
double[] data = this.fDecomposition.fData;
double[] trend = this.fDecomposition.fTrend;
double[] weights = this.fDecomposition.fWeights;
double[] seasonal = this.fDecomposition.fSeasonal;
for (int i = 0; (i < data.Length); i++)
{
seasonal[i] = this.fExtendedSeasonal[this.fPeriodLength + i] - this.fDeSeasonalized[i];
trend[i] = data[i] - seasonal[i];
}
// dumpDebugData("seasonal", seasonal);
// dumpDebugData("trend0", trend);
double[] residualWeights = useResidualWeights ? weights : null;
this.fLoessSmootherFactory.Data = trend;
this.fLoessSmootherFactory.ExternalWeights = residualWeights;
LoessSmoother trendSmoother = this.fLoessSmootherFactory.build();
//System.arraycopy(trendSmoother.smooth(), 0, trend, 0, trend.Length);
// dumpDebugData("trend", trend);
var sss = trendSmoother.smooth();
for (int i = 0; i < trend.Length; i++)
{
trend[i] = sss[i];
}
}
private void smoothOneSubSeries(double[] weights, double[] rawData, double[] smoothedData)
{
int cycleLength = rawData.Length;
// Smooth the cyclic sub-series with LOESS and then extrapolate one place beyond each end.
this.fLoessSmootherFactory.Data = rawData;
this.fLoessSmootherFactory.ExternalWeights = weights;
LoessSmoother smoother = this.fLoessSmootherFactory.build();
//Copy, shifting by 1 to leave room for the extrapolated point at the beginning.
// System.arraycopy(smoother.smooth(), 0, smoothedData, this.fNumPeriodsToExtrapolateBackward, cycleLength);
var ss = smoother.smooth();
for (int i = 0; i < cycleLength; i++)
{
smoothedData[this.fNumPeriodsToExtrapolateBackward + i] = ss[i];
}
LoessInterpolator interpolator = smoother.Interpolator;
// Extrapolate from the leftmost "width" points to the "-1" position
int left = 0;
int right = (left + (this.fWidth - 1));
right = Math.Min(right, (cycleLength - 1));
int leftValue = this.fNumPeriodsToExtrapolateBackward;
for (int i = 1; (i <= this.fNumPeriodsToExtrapolateBackward); i++)
{
double ys = interpolator.smoothOnePoint((i * -1), left, right);
//
smoothedData[(leftValue - i)] = ys == 0 ? smoothedData[leftValue] : ys;
}
// Extrapolate from the rightmost "width" points to the "length" position (one past the array end).
right = (cycleLength - 1);
left = ((right - this.fWidth) + 1);
left = Math.Max(0, left);
int rightValue = (this.fNumPeriodsToExtrapolateBackward + right);
for (int i = 1; (i <= this.fNumPeriodsToExtrapolateForward); i++)
{
Double ys = interpolator.smoothOnePoint((right + i), left, right);
//smoothedData[(rightValue + i)] = (ys == null);
smoothedData[rightValue + i] = ys == 0 ? smoothedData[rightValue] : ys;
}
}
public void smoothSeasonal(int width, bool restoreEndPoints)
{
// Ensure that LOESS smoother width is odd and >= 3.
width = Math.Max(3, width);
if (width % 2 == 0)
{
width++;
}
// Quadratic smoothing of the seasonal component.
// Do NOT perform linear interpolation between smoothed points - the quadratic spline can accommodate
// sharp changes and linear interpolation would cut off peaks/valleys.
LoessBuilder builder = new LoessBuilder();
builder.Width = width;
builder.Degree = 2;
builder.Jump = 1;
builder.Data = this.fSeasonal;
LoessSmoother seasonalSmoother = builder.build();
double[] smoothedSeasonal = seasonalSmoother.smooth();
// TODO: Calculate the variance reduction in smoothing the seasonal.
// Update the seasonal with the smoothed values.
// TODO: This is not very good - it causes discontinuities a the endpoints.
// Better to transition to linear in the last half-smoother width.
// Restore the end-point values as the smoother will tend to over-modify these.
double s0 = this.fSeasonal[0];
double sN = this.fSeasonal[(this.fSeasonal.Length - 1)];
//System.arraycopy(smoothedSeasonal, 0, this.fSeasonal, 0, smoothedSeasonal.Length)
this.fSeasonal = new double[smoothedSeasonal.Length];
for (int i = 0; i < smoothedSeasonal.Length; i++)
{
this.fSeasonal[i] = smoothedSeasonal[i];
}
if (restoreEndPoints)
{
this.fSeasonal[0] = s0;
this.fSeasonal[this.fSeasonal.Length - 1] = sN;
}
for (int i = 0; (i < smoothedSeasonal.Length); i++)
{
fResiduals[i] = fData[i] - fTrend[i] - fSeasonal[i];
}
}
private void removeSeasonality()
{
//
double[] pass1 = this.fExtendedSeasonal.MA(this.fPeriodLength);
// data.length + periodLength + 1
double[] pass2 = pass1.MA(this.fPeriodLength);
// data.length + 2
double[] pass3 = pass2.MA(3);
//
this.fLowpassLoessFactory.Data = pass3;
LoessSmoother lowPassLoess = this.fLowpassLoessFactory.build();
this.fDeSeasonalized = lowPassLoess.smooth();
// dumpDebugData("lowpass", fDeSeasonalized);
}
