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NAME HLC_combine - compute harmonic linear combinations of maps DESCRIPTION This program computes a harmonic linear combination (HLC) of the nine Planck temperature frequency maps (3 from LFI, 6 from HFI) with multipole-dependent weights to produce a spherical map. The (lmax+1)*9 harmonic weights are externally supplied (i.e., read from an input file) and can be determined from an algorithm like SMICA, for instance. When applied to Planck input data, the HLC output may be an estimated CMB map or the map of any other component, depending on the HLC weights. Of course, the application of the algorithm is not restricted to data maps; it can also be used to propagate noise simulations. The code is fully parallelized, a typical usage to compute a large number of simulations would be to distribute the work load over many nodes (using MPI), and enable OpenMP to work with a few cores per node on a single realization. It has been tested with recent versions of the Intel Fortran compiler using hybrid MPI and OpenMP parallelization. INSTALLATION Prerequisites: - Healpix - CFITSIO - Modern Fortran compiler with MPI wrapper Prior to compilation, edit the 'Makefile' to reflect your MPI compiler wrapper. Also, make sure that the CFITSIO library, and the Healpix library and include directories are correctly specified. USAGE The algorithm reads keyword - keyvalue pairs from a namelist in the configuration file 'input.cfg'. Here, the user is asked to specify FILE_IN_W8RING_DIR: Directory of the Healpix pixel weights, typically $HEALPIX/data. Only the directory should be specified, the file name itself will be appended according to the Healpix naming convention. FILE_IN_HLC_COEFF: HLC coefficients to be used to calculate the linear combination. It must be in ASCII table form, with 9 columns for the different frequencies, and lmax+1 rows. FILE_FILENAMELIST: Text file that contains the list of input and output file names, one entry per line. The file names must be provided in the following order: Input file simulation 1 LFI 30 GHz Input file simulation 1 LFI 44 GHz Input file simulation 1 LFI 70 GHz Input file simulation 1 HFI 100 GHz Input file simulation 1 HFI 143 GHz Input file simulation 1 HFI 217 GHz Input file simulation 1 HFI 353 GHz Input file simulation 1 HFI 545 GHz Input file simulation 1 HFI 857 GHz Output file simulation 1 Input file simulation 2 LFI 30 GHz Input file simulation 2 LFI 44 GHz Input file simulation 2 LFI 70 GHz Input file simulation 2 HFI 100 GHz Input file simulation 2 HFI 143 GHz Input file simulation 2 HFI 217 GHz Input file simulation 2 HFI 353 GHz Input file simulation 2 HFI 545 GHz Input file simulation 2 HFI 857 GHz Output file simulation 2 ... This text file must not contain comments, blank lines, whitespaces, etc. The format to specify the output file names follows the Healpix convention. That is, if it is prepended with an exclamation point, "!", possibly existing output files will be overwritten. The total number of simulations that can be supplied in the file and subsequently processed in a single run of the pipeline is currently limited to 10000. File names should contain absolute paths and be at most 150 characters long. RESTRICTIONS The software package HLC_combine does not implement a universal HLC. In its latest version, it is restricted to the Planck format in the sense that it assumes a total of nine input maps, the first three of which are provided at resolution nside=1024, and the last six at nside=2048. Input files are expected to be in the Healpix ordering scheme 'RING'. If maps are provided in 'NESTED' format, and a valid FITS header containing the "ORDERING='NESTED'" entry is present, the input will be automatically reordered into 'RING' scheme. Irrespective of the input, the output map will always be stored in single precision and 'RING' ordering. One MPI instance of the program demands about 4 GB of memory. Make sure that your computing environment complies with this requirement.