Examples

These examples demonstrate how to use the FFT operator.

The following example computes the spectrogram of a time series by using the FFT operator: 


use com.teracloud.streams.timeseries.analysis::FFT;
composite Main {
	graph
		//Compute the spectogram spectrum
	stream<list<float64> magnitude> spectogramStream=FFT(sineStream)
	{
		window
			sineStream: sliding, count(128), count(10);
		param
			inputTimeSeries: sine;
			useHamming: true;
			resolution: 128u;
			algorithm: complextFFT;
		output
			spectogramStream:
			magnitude=magnitude();
	}
}

The following example returns FFT values as list of complex64 data types. 


composite Main 
{
	type
	    ecgRawInput = tuple<float64 patientId,  float64 ecgValue>;
	    fftResult = tuple<list<complex64> fft, list<float64> magnitude, list<float64> pow-er>;
	graph
		stream <float64 id, list<float64> ecgValue> EcgRawInputRecord = FileSource() 
		{
			param
				file : "ts.csv";
				format : csv;
		}
		
		stream<fftResult> FftResultRecord = FFT(EcgRawInputRecord) 
		{
			param
				inputTimeSeries : ecgValue;
				useHamming : false;
				algorithm : complexFFT;
			output FftResultRecord : 
				fft = FFTAsComplex(), magnitude = magnitude(), power = power();
		}
		
		() as PowerSink = FileSink(FftResultRecord) 
		{
			param
				file: "FFT-power.csv";
				format: csv;
		}
}