1 Introduction

  Mn_Fit is an interactive fitting  and plotting package, that uses MINUIT
  to fit  histograms  or data  read in  from a file  and  displays the fit
  results on a  screen. Hardcopies of  pictures can  easily be made with a
  quality suitable  for publication.  Mn_Fit can also  be used purely as a
  plotting package without using the fitting.

  Features of the plotting include  user specification of all the plotting
  variables,  overlaying of  one or more  histograms or  functions and the
  trivial changing of  symbols used in plotting.  There are also secondary
  histogram identifiers so that you can keep track of data and Monte Carlo
  plots for example by giving them different secondary identifiers. If you
  make projections or slices of a  plot, they will be stored with the same
  primary identifier, but will be given a different secondary identifier.

  It is also  possible to  interactively  specify cuts on  a plot and then
  make projections of the plots using the cuts
  (see HELP CUT and HELP PROJECT).

  For   suitable  commands  you can  give a  range  of  either  primary or
  secondary identifiers for the  command  (e.g. `FET 1:300' will fetch all
  histograms with identifiers between 1 and 300); see HELP Identifiers.

  For details on the implementation of the MINUIT package see HELP MINUIT.
  It has all the standard  features available  plus several new ones, such
  as the ability to modify variables.

  Mn_Fit can be run either interactively or from a file or you can execute
  a series of  commands  in a file.  The exact  command to  run depends on
  where you are, but it has the general form `@disk:[directory]MN_FIT'. If
  the `DO' command is available you  should be able to say `DO MN_FIT'. On
  VXL3ON you can just give the  command mn_fit. The following is a list of
  some of the directories:

  Cornell:     UD2:[CLEO14.COM]       "Official version"
               UD1:[MN_FIT]           "Latest version"
  VXCERN:      DISK$L32:[BROCK]
  VXL3ON:      L3DAQ$GRA:             "Official version"
               USR0:[BROCK]           "Latest version"
  L3 Apollo:   /user/brock/mn_fit

  To run from a file issue the  command `DO MN_FIT filename'. To read from
  a file while  running interactively  issue the command
  `EXEC (or READ COMMAND) filename'. You can also define your own commands
  using the `DEFINE' command.

  When you  start up Mn_Fit  it will look  for the file  `MN_LOGON.MNF' in
  your local  directory and  if that does  not exist it  will look for the
  logical  name  `MN$LOGON'. The file  will be  executed and  then control
  given to the terminal.

  Functions  can be defined  interactively  using the CERN  COMIS package,
  meaning you can write  your own functions to  fit with without relinking
  Mn_Fit (see HELP COMIS and HELP FUNCTION LIST COMIS for more details).

  All commands can be abbreviated to  the point of ambiguity, and commands
  are read in using the TYPSCN package.

  Mn_Fit is designed, so that you do not have to know the complete command
  syntax, before starting to give a command. Just give the first word of a
  command and you should be prompted  for everything else needed. Within a
  command  you can  often get  more help  by typing  `?'. The  prompt will
  indicate if this is possible.

