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q [2009/08/06 15:40]
clare created
q [2009/08/27 12:18] (current)
clare
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 ====== q ====== ====== q ======
  
 +**[//​quick_refine//​ !E [//​quick_refine_remove//​ !E]]**
 +
 +//​quick_refine//​ removes parameters that influence <​sub>​{{techref_files:​image002.gif?​20x23}}</​sub>​ in a small manner during a [[#​k144|refinement cycle]]. Use of //​quick_refine//​ speeds up simulated annealing, see for example the macro Auto_T which is used in example AE1-AUTO.INP. All refined parameters are reinstated for refinement at the start of subsequent cycles. Large //​quick_refine//​ values aggressively removes parameters and convergence to low <​sub>​{{techref_files:​image002.gif?​20x23}}</​sub>​ maybe hindered. A value of 0.1 works well.
 +
 +//​quick_refine//​ has the following consequences:​
 +
 +  * If parameters are not reinstated using //​quick_refine_remove//​ then<​sub>​{{techref_files:​image002.gif?​20x23}}</​sub>​ does not get to its lowest possible value for a particular refinement cycle. 
 +  * The degree of parameter randomization increases with increasing values of //​quick_refine//​. Thus randomization should be reduced as //​quick_refine//​ increases. Alternatively //​randomize_on_errros//​ can be used which automatically determines the amount a parameter is randomized.
 +
 +//​quick_refine_remove//​removes a parameter from refinement if it evaluates to non-zero or reinstates a parameter if it evaluates to zero. It can be a function of the reserved parameters QR_Removed or QR_Num_Times_Consecutively_Small and additionally global reserved parameter names such as Cycle_Iter, Cycle and T. If //​quick_refine_remove//​ is not defined then the removal scheme of section 5.6 is used and parameters are not reinstated until the next refinement cycle.
 +
 +In most refinements the following will produce close to the lowest <​sub>​{{techref_files:​image002.gif?​20x23}}</​sub>​ and in a shorter time period (see for example PAWLEY1.INP). ​
 +
 +quick_refine .1
 +
 +   quick_refine_remove =
 +
 +      IF QR_Removed THEN
 +
 +         0 ' reinstate the parameter
 +
 +      ELSE
 +
 +         IF QR_Num_Times_Consecutively_Small > 2 THEN
 +
 +            1 ' remove the parameter
 +
 +         ELSE
 +
 +            0 ' dont remove the parameter
 +
 +         ENDIF
 +
 +      ENDIF;

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