SUGAIN - apply various types of gain to display traces                

 sugain <stdin >stdout [optional parameters]                           

 Required parameters:                                                  
       none (no-op)                                                    

 Optional parameters:                                                  
       panel=0         =1 gain whole data set (vs. trace by trace)	
       tpow=0.0        multiply data by t^tpow                         
       epow=0.0        multiply data by exp(epow*t)                    
       gpow=1.0        take signed gpowth power of scaled data         
       agc=0           flag; 1 = do automatic gain control             
       gagc=0          flag; 1 = ... with gaussian taper               
       wagc=0.5        agc window in seconds (use if agc=1 or gagc=1)  
       trap=none       zero any value whose magnitude exceeds trapval  
       clip=none       clip any value whose magnitude exceeds clipval  
       qclip=1.0       clip by quantile on absolute values on trace    
       qbal=0          flag; 1 = balance traces by qclip and scale     
       pbal=0          flag; 1 = bal traces by dividing by rms value   
       mbal=0          flag; 1 = bal traces by subtracting the mean    
       maxbal=0        flag; 1 = balance traces by subtracting the max 
       scale=1.0       multiply data by overall scale factor           
       norm=1.0        divide data by overall scale factor             
       bias=0.0        bias data by adding an overall bias value	
       jon=0           flag; 1 means tpow=2, gpow=.5, qclip=.95        
       verbose=0       verbose = 1 echoes info				


 	tmpdir=	 if non-empty, use the value as a directory path	
		 prefix for storing temporary files; else if the	
	         the CWP_TMPDIR environment variable is set use		
	         its value for the path; else use tmpfile()		

 Operation order:                                                      

 out(t) = scale * BAL{CLIP[AGC{[t^tpow * exp(epow * t) * ( in(t)-bias )]^gpow}]}

 Notes:                                                                
	The jon flag selects the parameter choices discussed in		
	Claerbout's Imaging the Earth, pp 233-236.			

	Extremely large/small values may be lost during agc. Windowing  
	these off and applying a scale in a preliminary pass through	
	sugain may help.						

	Sugain only applies gain to traces with tr.mark=0. Use sushw,	
	suchw, suedit, or suxedit to mark traces you do not want gained.
	See the selfdocs of sushw, suchw, suedit, and suxedit for more	
	information about setting header fields. Use "sukeyword mark
	for more information about the mark header field.		


 Credits:
      SEP: Jon Claerbout
      CWP: Jack K. Cohen, Brian Sumner, Dave Hale

 Note: Have assumed tr.deltr >= 0 in tpow routine.

 Technical Reference:
      Jon's second book, pages 233-236.

 Trace header fields accessed: ns, dt, delrt, mark