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Detecting where errors occurred in a Table[ ] calculation?

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  • Subject: [mg33807] Detecting where errors occurred in a Table[ ] calculation?
  • From: aes <siegman at>
  • Date: Tue, 16 Apr 2002 03:52:24 -0400 (EDT)
  • Organization: Stanford University
  • Sender: owner-wri-mathgroup at

I often test modules or numerical procedures by making a Table[ ] of test 
results for a range of input parameters; and this sometimes (well, maybe, nearly 
always) leads to error messages, like division by zero, or "FindRoot did not 
converge", for some but not all of the rows in the Table.  

Finding out *where* these errors occurred -- that is, for what ranges of the 
input parameter values -- then becomes an exercise in trial and error, removing 
values from one or the other end of various parameter ranges until the error 
messages go away.

It would be nice to have a simple way to test for whether any error occurred 
during the evaluation of each individual row in a Table, so that one could then 
insert say an "*" in a final column of that row to mark each row where an error 

Any simple way to accomplish this?  

(Don't really need to know what specific error occurred, just that there was 
some error.  And obviously, this could be accomplished by calculating and 
printing individual lines using a Do[ ] loop and seeing where the error messages 
fall -- although even that will fail after the third error of the same kind.)

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