// totallength and N are number of complex samples
void PeriodogramComponent::periodogram(int totallength,int N,float data[],float result[])
{
int num_of_block = 2*totallength/N-1;
float datablock[2*N],PSDresult[N],PSDresultshift[N];
int offset;
clearArray(result,N);
for( int i= 1;i<=num_of_block;i++)
{
offset = N/2*(i-1);
copyblock(offset,N,data,datablock);
winHan(N,datablock);
FFT (datablock, N, 1);
PSD(datablock,PSDresult,N);
PSDshift(PSDresult,PSDresultshift,N);
addArray(result,PSDresultshift,N);
}
avgArray(result,N,num_of_block);
}
int main(int argc, char *argv[])
{
# include "addTimeOptions.H"
# include "setRootCase.H"
# include "createTime.H"
// Get times list
instantList Times = runTime.times();
// set startTime and endTime depending on -time and -latestTime options
# include "checkTimeOptions.H"
runTime.setTime(Times[startTime], startTime);
# include "createMesh.H"
for (label i=startTime; i<endTime; i++)
{
runTime.setTime(Times[i], i);
Info<< "Time = " << runTime.timeName() << endl;
mesh.readUpdate();
IOobject tauHeader
(
"tau",
runTime.timeName(),
mesh,
IOobject::MUST_READ
);
// Check tau exists
if (tauHeader.headerOk())
{
mesh.readUpdate();
Info<< " Reading tau" << endl;
volSymmTensorField tau(tauHeader, mesh);
Info<< " Calculating PSD"<< endl;
volScalarField PSD
(
IOobject
(
"PSD",
runTime.timeName(),
mesh,
IOobject::NO_READ
),
Foam::sqrt
(
Foam::sqr(tau.component(symmTensor::YY)
- tau.component(symmTensor::XX))
+ 4*Foam::sqr(tau.component(symmTensor::XY))
)
);
PSD.write();
}
else
{
Info<< " No tau" << endl;
}
Info<< endl;
} //for time
Info<< endl;
Info<< " End"<< nl << endl;
return(0);
}
