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Thread: Parameter values NaN in UMING

  1. #1
    Junior Member
    Join Date
    Dec 2009

    Parameter values NaN in UMING

    I am using UMING to find a solution for a multivariate function. The program is running well on most of the applications. However, once in a while, it crashes and the reason is that the trial values of the parameters at the beginning of a new iteration become NaN.
    To make sure that I know when the problem occurs, I print the argument values at the beginning of each iteration.
    I would appreciate if someone can give me a hint why it occurs.

  2. #2
    Once introduced the NaN(s) will propagate. I would print and verify that the returned values from FCN & GRAD are all valid, then double check all inputs to UMING.

  3. #3
    Senior Member mecej4's Avatar
    Join Date
    Dec 2009

    There is not enough information in your query to give you an answer. There are a number of reasons why NaNs may occur where they are not expected, and most of them relate to programming errors of some sort. Finding NaNs in such circumstances is actually beneficial, since they flag the presence of errors that would otherwise go undetected.

    A short working example source code that displays the problem mentioned would make it feasible to narrow down the possible causes.
    Last edited by mecej4; 11-02-2012 at 06:31 PM.

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