Compute the power spectrum of a real function.


call SHPowerSpectrum (cilm, lmax, pspectrum, exitstatus)


cilm : input, real(dp), dimension (2, lmaxin+1, lmaxin+1)
The function expressed in real spherical harmonics.
lmax : input, integer
The maximum spherical harmonic degree used in calculating the power spectrum. This must be less than or equal to lmaxin.
pspectrum : output, real(dp), dimension (lmax+1)
The power spectrum of the function.
exitstatus : output, optional, integer
If present, instead of executing a STOP when an error is encountered, the variable exitstatus will be returned describing the error. 0 = No errors; 1 = Improper dimensions of input array; 2 = Improper bounds for input variable; 3 = Error allocating memory; 4 = File IO error.


SHPowerSpectrum will calculate the power spectrum of a function expressed in real 4-pi normalized spherical harmonics. For a given spherical harmonic degree l, this is calculated explicitly as:

pspectrum(l) = Sum_{i=1}^2 Sum_{m=0}^l cilm(i, l+1, m+1)**2.

See also

shpowerl, shpowerdensityl, shcrosspowerl, shcrosspowerdensityl, shpowerspectrumdensity, shcrosspowerspectrum, shcrosspowerspectrumdensity, shadmitcorr

Tags: fortran
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