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SHPowerSpectrum
Compute the power spectrum of a real function.
Usage
call SHPowerSpectrum (cilm
, lmax
, pspectrum
, exitstatus
)
Parameters
cilm
: input, real*8, 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*8, 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.
Description
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
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