NAME

     mixn  - do simple mixing or median smoothing of  samples  on
     seismic traces

SYNOPSIS

     mixn [ -Nntap ] [ -Ootap ] [ -mmix ] [ -wamp ] [ -sist  ]  [
     -eied  ]  [ -nsns ] [ -nene ] [ -rsirs ] [ -reire ] [ -M ] [
     -V ] [ -? ]

DESCRIPTION

     (1) mixn computes a simple odd-length 1/x  type  filter  and
     convolves this with seismic traces read from the input.  The
     center value of the filter is always 1.0.  Values on  either
     side  of the center value are now computed by raising amp to
     the ith power as i increments away from the center value.

     (2) mixn does a simple odd-length m-point  median  smoothing
     of  the input data. The output of the median filter is keyed
     to the center point of the filter.

     This program works on seismic traces. To run this in a  spa-
     tial  mode  you must first run transp, pipe that output into
     mixn, then pipe the output into  another  transp.   You  can
     also  process  records  directly  with the companion program
     mixrec without the transp filters but this runs slow on  the
     crays.

     mixn gets both its data and its parameters from command line
     arguments.   These  arguments specify the input, output, the
     filter length, the filter weight, the start and end  traces,
     whether or not to do median smoothing, and verbose printout,
     if desired.

  Command line arguments
     -N ntap
          Enter the input data set name or file immediately after
          typing -N unless the input is from a pipe in which case
          the -N entry must be omitted.  This input  file  should
          include the complete path name if the file resides in a
          different directory.  Example -N/b/vsp/dummy tells  the
          program to look for file 'dummy' in directory '/b/vsp'.

     -O otap
          Enter the output data  set  name  or  file  immediately
          after typing -O.  This output file is not required when
          piping the output to another process.  The output  data
          set also requires the full path name (see above).

     -m mix
          Enter the odd length of the  mixing  filter  in  points
          (default = 3).

     -w amp
          Enter  the  filter  weight  in  the  range  0.0  -  1.0
          (default = 0.5).  If this entry is greater than 1.0 the
          program will assume it is meant to  be  a  percent  and
          convert  to  a fraction.  This is useful when inputting
          to scripts when integers not reals are handled.

     -s ist
          Enter the start time (ms) for mixing. Times above  this
          will be passed untouched. Default = first sample.

     -e ied
          Enter the end time (ms) for mixing.  Times  below  this
          will be passed untouched. Default = last sample.

     -ns ns
          Enter the start trace for mixing.  Traces  before  this
          will be passed untouched. Default = first trace in each
          record.

     -ne ne
          Enter the end trace for mixing. Traces after this  will
          be  passed  untouched.  Default  =  last  trace in each
          record.

     -rs irs
          Enter the start record for mixing. Records before  this
          will  be  passed  untouched.  Default = first record in
          data set.

     -re ire
          Enter the end record for  mixing.  Records  after  this
          will be passed untouched. Default = last record in data
          set.

     -M   Enter the command  line  argument  '-M'  to  do  median
          smoothing. In this case the weights are disregarded.

     -V   Enter the command line argument '-V' to get  additional
          printout.

     -?   Enter the command line  argument  '-?'  to  get  online
          help.   The program terminates after the help screen is
          printed.

BUGS

     Unkown as yet

SEE ALSO

     mixrec

AUTHOR

     P. R. Gutowski (at Felinski's request)

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.