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133 lines
5.3 KiB
Text
133 lines
5.3 KiB
Text
/*! \mainpage HEALPix C++ documentation
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<ul>
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<li>\ref components "Programming interface"
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<li>\ref facilities "Facilities"
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</ul>
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*/
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/*! \page components Code components
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Classes:
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- Healpix_Base contains all functionality related to the HEALPix
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pixelisation which does not require actual map data.
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- Healpix_Base2 is analogous to Healpix_Base, but allows for much
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higher resolutions.
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- Healpix_Map is derived from Healpix_Base and implements
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additional functionality like change of the ordering scheme, up- and
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degrading and interpolation.
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- Alm is used to store spherical harmonic coefficients.
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- PowSpec is used to store \f$C_l\f$ coefficients.
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Conversions between different data types:
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- \ref alm_healpix_group "HEALPix maps <-> a_lm".
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- \ref alm_ps_group "power spectra <-> a_lm".
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FITS I/O:
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- for \ref healpix_map_fitsio_group "HEALPix Maps"
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- for \ref alm_fitsio_group "spherical harmonic coefficients"
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- for \ref powspec_fitsio_group "power spectra"
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*/
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/*! \page facilities HEALPix C++ facilities
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\section syn_alm_cxx
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This program reads a set of \f$C_l\f$ from disk and converts it to
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a set of \f$a_{lm}\f$.
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\verbinclude syn_alm_cxx.par.txt
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\section alm2map_cxx
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This program reads a set of \f$a_{lm}\f$ from disk and converts them to
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a HEALPix map.
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\verbinclude alm2map_cxx.par.txt
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\section anafast_cxx
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This program performs harmonic analysis of a HEALPix map up to a
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user-specified maximum spherical harmonic order \f$l_{\mbox{max}}\f$.
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The integrals are computed on the whole sphere.
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Scalar, or scalar and tensor, spherical harmonic coefficients are evaluated
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from the map(s) if the input provides, respectively, only the temperature,
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or temperature and polarisation maps.
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The total operation count scales as \f${\cal {O}}(N_{\mbox{pix}}^{3/2})\f$
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with a prefactor depending on \f$l_{\mbox{max}}\f$.
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Anafast_cxx reads a file containing the map(s) and produces a file
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containing the temperature power spectrum \f$C^T_l\f$ and, if requested,
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also the polarisation power spectra \f$C^E_l\f$, \f$C^B_l\f$ and
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\f$C^{T\times E}_l\f$. The \f$a_{lm}\f$ coefficients computed during the
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execution also can be written to a file if requested.
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Anafast_cxx executes an approximate, discrete point-set quadrature on
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a sphere sampled at the HEALPix pixel centers.
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Spherical harmonic transforms are computed using recurrence relations for
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Legendre polynomials on co-latitude (\f$\vartheta\f$) and Fast Fourier
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transforms on longitude (\f$\varphi\f$).
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Anafast permits two execution options which allow a significant
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improvement of accuracy of the approximate quadrature performed by
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this facility:
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- An improved analysis using the provided ring weights, which correct the
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quadrature on latitude, and/or
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- An iterative scheme using in succession several backward and forward
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harmonic transforms of the maps.
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\verbinclude anafast_cxx.par.txt
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\section map2tga
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This program reads in a HEALPix sky map in FITS format and generates an
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image in TGA format. map2tga allows the selection of the projection
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scheme (Mollweide or Gnomonic for small patches of the sky), color
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table, color bar inclusion, linear or log scaling, maximum and
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minimum range for the plot and plot-title. The facility provides
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a command-line interface, but can also read a parameter file.
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\verbinclude map2tga.par.txt
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\section rotalm_cxx
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Performs a coordinate transformation on a set of \f$a_{lm}\f$.
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\verbatim
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Usage: rotalm_cxx <infile> <outfile> <itransform> <pol>
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Transform 1: Equatorial (2000) -> Galactic (2000)
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2: Galactic (2000) -> Equatorial (2000)
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3: Equatorial (2000) -> Ecliptic (2000)
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4: Ecliptic (2000) -> Equatorial (2000)
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5: Ecliptic (2000) -> Galactic (2000)
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6: Galactic (2000) -> Ecliptic (2000)
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7: Equatorial (1950) -> Galactic (1950)
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8: Galactic (1950) -> Equatorial (1950)
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9: Equatorial (1950) -> Ecliptic (1950)
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10: Ecliptic (1950) -> Equatorial (1950)
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11: Ecliptic (1950) -> Galactic (1950)
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12: Galactic (1950) -> Ecliptic (1950)
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\endverbatim
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\section mult_alm
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This program reads a set of (unpolarised or polarised) \f$a_{lm}\f$,
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removes pixel window functions and/or Gaussian beams, applies different
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pixel window functions or Gaussian beams, and outputs the result.
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\verbinclude mult_alm.par.txt
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\section smoothing_cxx
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This program reads a (unpolarised or polarised) HEALPix map, converts it
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to \f$a_{lm}\f$, performs a smoothing operation with a Gaussian beam,
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converts the \f$a_{lm}\f$ back to a map and outputs the result.
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\verbinclude smoothing_cxx.par.txt
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\section calc_powspec
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This program reads one or two sets of \f$a_{lm}\f$, extracts the
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(unpolarised or polarised) power spectrum or the unpolarised cross power
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spectrum, and outputs the result.
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\verbatim Usage: calc_powspec <almfile1> [<almfile2>] <powspec_file>\endverbatim
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\section median_filter_cxx
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This program inputs a HEALPix map, runs a median filter with the desired
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radius on it and saves the result to another file.
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\verbatim Usage: median_filter_cxx <input map> <output map> <radius in arcmin>\endverbatim
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*/
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