Changes between Initial Version and Version 1 of Ticket #28159, comment 119


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Timestamp:
10/18/19 22:25:24 (3 years ago)
Author:
gh-DeRhamSource
Comment:

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  • Ticket #28159, comment 119

    initial v1  
    22> Again, I don't like so much the methods `is_unit()` added to the classes `ChartFunction` and `ScalarField`. They don't reflect fully the mathematical meaning of being a unit element of a ring. Do you really need these in this ticket? (I don't see clearly the connection with vector bundles).
    33
    4 I'm not quite sure, but I think this method is mandatory when using the division free algorithm. And the division free algorithm is invoked when changes of frames are established. In general, for vector bundles, frames may be distributed over serveral chart domains, for which the SR enforcement method fails. So yes, this is related to this ticket. I'm not completely satisfied with this either. As soon as the issue in ticket #28629 is solved, this snippet can be deleted again. Should I add a comment about this?
     4I'm not quite sure, but I think this method is mandatory when using the division free algorithm. And the division free algorithm is invoked when changes of frames are established. In general, for vector bundles, frames may be distributed over serveral chart domains, for which the SR enforcement method fails. So yes, this is related to this ticket. I'm not completely satisfied with this either. As soon as the issue in ticket #28629 is solved, this snippet can be deleted again. Should I add a comment in the code about this?
    55
    66> Side note: `self.is_zero()`, as invoked in `ChartFunction.is_unit()`, can be very time consuming for large symbolic expressions, since it is trying to simplify the expression to zero. In this respect, the use of `is_trivial_zero()` in `ScalarField.is_unit()` is better.