This helpfile describes the factors that determine                      
        how long a TURF command will take to run.                               
        This section was last updated on Sept 16, 2006.                         
                                                                                
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              *  processing speed: cases and combinations  *                    
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        There are three components whose effect on the speed                    
        of a TURF run is more or less linear:                                   
                                                                                
          (1) more cases.  Twice the cases for the same analysis                
              will take twice the time.                                         
                                                                                
          (2) more combinations to be tested.                                   
              30 items taken 6 at a time (ie, 30,6) has 593,775                 
              combinations, 30,7 has 2,035,800.                                 
              That is 3.4 times as many combinations.                           
              Therefore, it will take 3.4 times longer to run.                  
                                                                                
          (3) CPU speed. Since the data and the results are held                
              within memory during a run, going from an 800 mHz chip            
              to a 2.4 GHz chip should be about 3 times faster.                 
                                                                                
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              *  processing speed: effects of various options  *                
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        TURF speed is also greatly affected by the options chosen.              
        The fastest run is one that uses none of the options:                   
        for example,  TURF INFILE,  SIZE 6,  REACH.RESULTS OUTFILE $.           
                                                                                
        If this takes one second, how much longer do the various                
        options take ?                                                          
                                                                                
          (1) 10 seconds if adding just CASE WEIGHTING.                         
                                                                                
          (2) 28 seconds if using response weighting, item weighting            
              or reach threshold (with or without case weighting).              
                                                                                
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              *  processing speed: output files  *                              
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        The various output files take very little extra time.                   
                                                                                
        A  29,7 run for 500 cases with no output files took 2.5                 
        seconds. Adding the default sized (best 100) REACH.RESULTS              
        or FREQ.RESULTS files made the runtime 2.7 seconds;                     
        doing both took 2.8 seconds.                                            
                                                                                
        Asking for the 20,000 best REACH.RESULTS results instead                
        of the default best 100 took 3.1 seconds instead of 2.7.                
                                                                                
        The REACH.SUMMARY and FREQ.SUMMARY output files take a little           
        more time than the REACH.RESULTS and FREQ.RESULTS files.                
        The FULL.OUTPUT file takes almost no extra time since there             
        is no sort management involved.