Setting up a recursive loop in jsl

Question

hi,

I've built a long script where a curve fitting is performed iteratively on a large data table which many variables listed in 1 column. However at the end of the process some of those variables are not fitted (the process failed for one reason or another). At this point, I create a 'failed fitting' list of the variables that were not fitted in the previous and create a subset from the source table  (select where/contains/subset) and run part of the initial script again (that portion of the script is wrapped in an expression) on the subset table (selected rows, all columns) .

At the end of the second round of fitting, a new  'failed fitting ' list is created (typically smaller).

I'm trying to find a way to create a recursive loop where the code would look for the size of the last  'failed fitting' list and if it is greater than 0 and different from the previous 'failed fitting' list, it will initiate another round of fitting until the 'failed fitting'=0 or is identical to the previous 'failed fitting' list ( to avoid creating an infinite loop).

Any suggestions would be greatly appreciated.

Sebastien

Sburel · Answer

@Craige_Hales Thanks a lot for the suggestion. I will try this strategy.

Sebastien

Craige_Hales · Answer

I would not use recursion for this. Use a list of WorkToBeDone and a list of WorkCompleted and a flag FoundSomething. Write your loop something like this:

good = function({ method, item), 
// use the current strategy/method to test the item
// return 1 if pass, 0 if fail
);

FoundSomething = 1; // flag: are we still making progress?
strategy = 1; // maybe change the strategy after each round
while(FoundSomething,
    FoundSomething = 0;
    for(i = nitems(WorkToBeDone), i>=1, i -= 1, // backwards because removing items
        if( good( strategy, WorkToBeDone[i] ),
            insertinto(WorkCompleted, removefrom(WorkToBeDone,i));
            FoundSomething = 1;
        )
    );
    strategy += 1; // new strategy for next round
);

Sburel · Answer

Hi @jthi,

Thanks for your original input. Unfortunately, I have not managed to turn your suggestion into a workable script.

So I'm attaching another description of my objective (not a function script but rather a 'workflow').

Hopefully, someone can point me in the right direction.

Thanks

Sebastien

names default to here(1);
clear log();

sourcefitting={"a","b","c","d","e","f"};
/*The sourcefitting list can be 1000s longs and split in batches to perform some curve fitting, parameter extraction and them summarization using a FOR loo into a master table. 
The process is expected to fail on some of those batches. 
The failed items are identifed/listed into the 'failedfitting" list. 
At which point a recursive loop using 'processX' needs to be implemented to take care of the remaining items using a new round of batching and fitting (for some reason the 'failing' process works on smaller batches but predicting which one will failed is not possible hence the need for a recessive loop), until the 'failedfittingX' list' is either empty or is stagnating (processfitting=1) ie the process keeps on failing and running the process another round is not longer warranted.
 */

processX=expr(/* process XYZ*/ //each time the processX is run 2 list are generated "succesfittingX" and "failedfittingX" are generated

//A new list "successfittingX" is generated at the end of the recursive loop
successfitting0={"a","c","d"};
/*
successfitting1={"a","c","d","b"};
successfitting2={"a","c","d","b","e"};
successfitting3={"a","c","d","b","e","f"}*/;// or successfitting3={"a","c","d","b","e"};
successfitting=successfittingX;

//The successfittingX and the sourcefitting lists are compared and a resulting list "failedfittingX" is created:

failedfitting0={"b","e","f"};
/*
failedfitting1={"e","f"};
failedfitting2={"f"};
failedfitting3={}*/; // or failedfitting3={"f"};
failedfitting=failedfittingX;
failednb=Nitems(failedfitting);
if(failedfittingX==failedfittingX-1,progressfitting=1, progressfitting=0);
);

//The issue is about correctly defining the structure recursive loop which uses the previous list to determine wheter the process needs to keep on going or if it is completed
// the use of the function 'recurse' has been suggested

testrec=function({failednb},
		if(failednb>0&processfitting=0 ,recurse( processX),show("Done"))
);
testrec(failednb);