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SHPowerSpectrum (Fortran) |
spherical harmonics software package, spherical harmonic transform, legendre functions, multitaper spectral analysis, fortran, Python, gravity, magnetic field |
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shpowerspectrum.html |
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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
.
shpowerl, shpowerdensityl, shcrosspowerl, shcrosspowerdensityl, shpowerspectrumdensity, shcrosspowerspectrum, shcrosspowerspectrumdensity, shadmitcorr