/*
newDFTFunc
Purpose:
Forward DFT for a double array of samples of size n. This
converts data in the time domain to the frequency domain.
This will perform pythagorus to convert the complex array
directly to usable data for the frequency domain chart.
Parameters:
s: Signal we are changing
n: Size of the signal
*/
public double[] newDFTFunc(double[] s, int n)
{
double[] amplitude = new double[n];
double temp;
newComplex cmplx;
double re; /*real*/
double im; /*imaginary*/
for (int f = 0; f < n - 1; f++)
{
re = 0;
im = 0;
for (int t = 0; t < n - 1; t++)
{
re += s[t] * Math.Cos(2 * Math.PI * t * f / n);
im -= s[t] * Math.Sin(2 * Math.PI * t * f / n);
}
cmplx = new newComplex(re, im);
temp = (cmplx.getReal() * cmplx.getReal()) + (cmplx.getImaginary() * cmplx.getImaginary());
temp = Math.Sqrt(temp);
amplitude[f] = temp; // These are the points we are going to plot.
}
return amplitude;
}
/*
runningDFT
Purpose:
This is the DFT function that will be used with threads. This
will take in the number of threads specified by the user, and
run DFT for that selection on the whole array. This will then
be set to a speccific array for that thread number and used
back in the threadDFT funciton to copy the array to the
array that will be passed back to the windows form.
Parameters:
s: Wave data that will be processed
n: Length of the wave to be processed
threadNum: Current thread being run
maxThreads: Number of threads specified by the user
*/
private void runningDFT(double[] s, int n, int threadNum, int maxThreads)
{
int thNum = threadNum;
double temp;
newComplex cmplx;
double re; //real
double im; //imaginary
int startP = ((n / maxThreads) * (thNum - 1)), endP = ((n / maxThreads) * (thNum));
if(startP < 0)
{
startP = 0;
}
if (thNum == maxThreads - 1)
{
endP = n;
}
for (int f = startP; f < endP; f++) // run through first half
{
re = 0;
im = 0;
for (int t = 0; t < n - 1; t++)
{
re += s[t] * Math.Cos(2 * Math.PI * t * f / n);
im -= s[t] * Math.Sin(2 * Math.PI * t * f / n);
}
cmplx = new newComplex(re, im);
temp = (cmplx.getReal() * cmplx.getReal()) + (cmplx.getImaginary() * cmplx.getImaginary());
temp = Math.Sqrt(temp);
threadAmplitude[f] = temp; // These are the points we are going to plot.
}
}
