shpowerspectrumdensity.1

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.TH "shpowerspectrumdensity" "1" "2021-02-15" "Fortran 95" "SHTOOLS 4.10"
.hy
.SH SHPowerSpectrumDensity
.PP
Compute the power spectral density of a real function.
.SH Usage
.PP
call SHPowerSpectrumDensity (\f[V]cilm\f[R], \f[V]lmax\f[R],
\f[V]pspectrum\f[R], \f[V]exitstatus\f[R])
.SH Parameters
.TP
\f[V]cilm\f[R] : input, real(dp), dimension (2, \f[V]lmaxin\f[R]+1, \f[V]lmaxin\f[R]+1)
The real function expressed in real spherical harmonics.
.TP
\f[V]lmax\f[R] : input, integer(int32)
The maximum spherical harmonic degree used in calculating the power
spectrum.
This must be less than or equal to \f[V]lmaxin\f[R].
.TP
\f[V]pspectrum\f[R] : output, real(dp), dimension (\f[V]lmax\f[R]+1)
The power spectral density of the function.
.TP
\f[V]exitstatus\f[R] : output, optional, integer(int32)
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.
.SH Description
.PP
\f[V]SHPowerSpectrumDensity\f[R] will calculate the power spectral
density of a function expressed in real 4-pi normalized spherical
harmonics.
For a given spherical harmonic degree \f[V]l\f[R], this is explicitly
calculated as:
.PP
\f[V]pspectrum(l) = Sum_{i=1}\[ha]2 Sum_{m=0}\[ha]l cilm(i, l+1, m+1)**2 / (2l + 1)\f[R].
.SH See also
.PP
shpowerl, shpowerdensityl, shcrosspowerl, shcrosspowerdensityl,
shpowerspectrum, shcrosspowerspectrum, shcrosspowerspectrumdensity,
shadmitcorr