##marx_plots.pro: This procedure creates a postscript file containing
                plots of MARX output. The plots it creates:
                ypos vs. zpos, output spectrum/spectra (for HETG),
                pha vs. dd (2 plots for HETG), input spectrum,
                and a list of sim. information (eg. total cts,
                time, etc.).

USAGE: marx_plots, dir, PARFILE = parfile, PSFILE = psfile

 dir = Directory containing the MARX output
 PARFILE (Keyword) = The name of the parameter file, if it
                     is *not* marx.par. (Default value=marx.par.)

 PSFILE (Keyword)  = The name of the postscript file to which
                     the plots are to be written. The default 
                     value is marx_plots.ps.

 Procedures used by marx_plots.pro:
    - get_input_spec.pro
    - grating_spec.pro
    - read_marx_data.pro
    - read_parfile.pro        [ FUNCTION ]
    - tg_extract.pro


get_input_spec.pro: This procdure is used by marx_plots.pro

##grating_spec.pro: This procedure will extract a grating spectrum
                  from MARX output.

USAGE: grating_spec, marxdir, spectrum, GRATING = grating, SCALE = scale,
   ORDER = order

marxdir = the directory containing the marx output
spectrum = The vector returned by grating_spec. It is either 
            2xN dimensional or 4xN dimensional, depending on
            which grating was used. If grat=LETG, spectrum = 2xN,
            where the dimensions are ENERGY (or WAVELENGTH) and
            CTS/SEC. If grat=HETG, spectrum = 4xN dimensional.
            spectrum(0,*) = ENERGY (WAVE.), spectrum(1,*) = CTS/SEC
            for the MEG, spectrum(2,*),spectrum(3,*) = ENERGY (WAVE)
            and CTS/SEC for the HEG.

GRATING = grating   Set this keyword if there is no marx.par file
                    in the output dir. Otherwise, the program will
                    read the parameter file to obtain the grating.

SCALE = scale       Set SCALE = wave to get a wavelength scale. Otherwise,
                    the scale will be ENERGY

ORDER = order        Set ORDER = 2, 3, 4, . . . etc. to extract a spectrum
                     of a particular order. The default value is to use
                     the first order.

 **NOTE that this program "CHEATS" by extracting only events for the
   given order, using the order.dat data.**


##read_parfile.pro:  This is a FUNCTION which will return a selected
                     parameter from a parameter file.

USAGE:  parvalue = read_parfile('parname', PARFILE=parfile, MARXDIR=marxdir)
 
where 'parname' is the name of the parameter *spelled exactly as it is 
in the parameter file*. 

PARFILE = parfile - set this if the parameter file is not marx.par
MARXDIR = marxdir - the directory containing the par file


EXAMPLE: rowland = read_parfile('RowlandDiameter', PARFILE = 'simulation.par')

## read_marx_file.pro: This is a FUNCTION which will read a marx output file
                       and return the data in a vector.

 EXAMPLE: ypos = read_marx_file('marx_dir/ypos.dat')

## read_marx_data.pro: This is a PROCEDURE which will read in the ypos, zpos,
                       time, order and pha data from the marx output dir.

USAGE: read_marx_data, marxdir, ypos, zpos, time, order, pha

marxdir : The name of the directory containing the marx output

ypos, zpos, time, order, pha: The vectors containing the marx output. These
                              are returned by the procedure.