Changes between Initial Version and Version 1 of Ticket #5817, comment 29


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Timestamp:
2021-04-07T14:05:06Z (4 years ago)
Author:
Karim Adbdelhak

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  • Ticket #5817, comment 29

    initial v1  
    1414 x - y = 5.0;
    1515}}}
    16 Replacing one equation of the loop with this equation triggers index reduction which would go undetected without it. It transforms an analytical to a structural singularity. This does only
    17 seem to be relevant for systems where index reduction is applied, which is not true in general.
    18 It needs to applied on any system that is not known in prior to be balanced and regular, which includes the initial system. We could look at the presented system and assume that one of the
    19 equations belonging to the loop (3-5) are only part of the initial and not the simulation problem. In that case ASSC would not find it analyzing the simulation system, but it would still be needed for initialization since it changes the way the states need to be initialized. Unhandled this leads to the singular matrices at hand.
     16Replacing one equation of the loop with this equation triggers index reduction which would go undetected without it. It transforms an analytical to a structural singularity. This does only seem to be relevant for systems where index reduction is applied, which is not true in general. It needs to applied on any system that is not known in prior to be balanced and regular, which includes the initial system. We could look at the presented system and assume that one of the equations belonging to the loop (3-5) are only part of the initial and not the simulation problem. In that case ASSC would not find it analyzing the simulation system, but it would still be needed for initialization since it changes the way the states need to be initialized. Unhandled this leads to the singular matrices at hand.
    2017
    2118Resolving this once again is a problem with the order of operations in the old backend. Reshuffle Loops and the Balancing of initialization was done before and independent of Matching. Balancing the initial system should happen just like index reduction, during the matching process. It is just another way of resolving singularities. This method is implemented in the new backend, but would need to much restructuring in the current backend. It worked with reshuffle loops, because it was handled independently, but doing that is just double the work. ASSC needs to happen before the balancing of initialization and I could extract ASSC to be handled outside of matching, but it would just do a matching itself... unnecessary work. Here are the current pipelines in the old an new backend: