Sample code for strain calculation

calchlm.py

    # Strain via ffi method
    def calchlm(this,w22=None):

        # Calculate strain according to the fixed frequency method of http://arxiv.org/pdf/1006.1632v3

        #
        from numpy import array,double

        # If there is no w22 given, then use the internally defined value of wstart
        if w22 is None:
            # w22 = this.wstart
            # NOTE: here we choose to use the ORBITAL FREQUENCY as a lower bound for the l=m=2 mode.
            w22 = this.wstart_pn


        # Reset
        this.hlm = []
        for y in this.ylm:

            # Calculate the strain for each part of psi4. NOTE that there is currently NO special sign convention imposed beyond that used for psi4.
            w0 = w22 * double(y.m)/2.0 # NOTE that wstart is defined in characterize_start_end() using the l=m=2 Psi4 multipole.
            # Here, m=0 is a special case
            if 0==y.m: w0 = w22
            # Let the people know
            if this.verbose:
                alert( magenta('w%i%i = m*w22/2 = %f' % (y.l,y.m,w0) )+yellow(' (this is the lower frequency used for FFI method [arxiv:1006.1632v3])') )

            # Create the core waveform information
            t       =  y.t
            h_plus  =  ffintegrate( y.t, y.plus,  w0, 2 )
            h_cross =  ffintegrate( y.t, y.cross, w0, 2 )