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Thread: IMSL Daspg error message

  1. #1
    Junior Member
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    Aug 2011
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    IMSL Daspg error message

    Dear all,

    When I execute routine DASPG (IMSL 6.0) finds an approximation to the solution of a system of differential-algebraic equations g(t, y, yʹ) = 0, with given initial data for y and yʹ , sometimes will occur :


    *** TERMINAL ERROR 5 from DD3SPG. At T = 5.136200000003068D-01 and stepsize
    *** H = 1.490116119377984D-16, the error test failed repeatedly or
    *** with abs(H)=hmin.
    Here is a traceback of subprogram calls in reverse order:
    Routine name Error type Error code
    ------------ ---------- ----------
    DD3SPG 5 5 (Called internally)
    DD2SPG 0 0 (Called internally)
    DDASPG 0 0
    USER 0 0


    How do I correct this wrong question? Please help!

  2. #2
    Senior Member
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    Albuquerque, NM USA
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    There are a number of issues that could be causing this error message. Without seeing the code it is hard to diagnose. Candidates:

    - Initial conditions are not consistent
    - Jacobian is not computed correctly
    - Problem has index > 1

    But there are others possible. Either get in touch with post-sales support or post a code snip that yields this error message.

    You are using IMSL Fortran V. 6. The release V. 7 has an improved version of a DAE solver that you may find useful. But the error you are seeing is not going to be fixed by this upgrade.
    __________________
    Dickie T. Bird

  3. #3
    Junior Member
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    IMSL Daspg error message

    Dear Mr. Hanson,

    Thanks for your reply of possible diagnoses.

    I would like to further explain my problem. In my study, I try to deal with structural dynamics interaction between two structure bodies. There is a pair of constraint forces between them. One of the constraint force suddenly vanished when the two structure bodies were moving on a certain phase. An error message occurred as follows:

    *** TERMINAL ERROR 5 from DD3SPG. At T = 5.136200000003068D-01 and stepsize
    *** H = 1.490116119377984D-16, the error test failed repeatedly or
    *** with abs(H)=hmin.
    Here is a traceback of subprogram calls in reverse order:
    Routine name Error type Error code
    ------------ ---------- ----------
    DD3SPG 5 5 (Called internally)
    DD2SPG 0 0 (Called internally)
    DDASPG 0 0
    USER 0 0

    I supposed it's a discontinuity problem in DAE.
    How can I solve this problem when using IMSL Daspg
    subroutine?

  4. #4
    Senior Member
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    Sep 2005
    Location
    Albuquerque, NM USA
    Posts
    140
    I understand the problem better, perhaps. Let me try this: You have a system of DAEs . At some there is a discontinuity in . A working assumption of DASPG() is continuity of in its three variables. The continuity assumption appears to abruptly stop being true at this .

    The ideal organization for this type of model change - called g-stops in the ODE community - is to provide the function information describing g-stops and have the code gracefully continue with the new model and integrate beyond .

    But DASPG() does not have this g-stop feature, so you will have to do things yourself if you wish to use it. In other words discover before the code stops on this message. Then restart integration with the modified model for . You can also turn off printing and stopping when encountering this terminal error and see if this allows you to recover the value of . This has not been tried but you can experiment.
    Last edited by Richard Hanson; 09-05-2011 at 03:29 PM.

  5. #5
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    Oct 2012
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