(1) ippgen:   --> file.ipp
(2) ippsolve: file*.ipp --> file.isr
(3) isrplt:   file.isr --> file.dat (for ingesting into gnuplot)
(4) isrtex:   file.isr --> file.tex (for ingesting into latex)



(1) The ippgen utility creates interval programming problems (with .ipp suffix)

ippgen -s --dom=$DOM --build="$BLD#smart_amount=0"    --ipfs=$IPFS xfile_0400.ipp --dir=$DIR --amt=$AMT

(2) The ippsolve utility solves IvP problems (input file.ipp) and creates file.isr

(3) The isrplot utility 
    isrplot is a utility for converting an .isr (results)    
    file into a file suitable for ingesting into gnuplot.    
    The user selects the x-axis, the y-axis is always time.  
    The input file can be inferred if it begins with .isr    
    The output file can be inferred if it begins with .plt   
    or the .dat suffix.