#913 SIMPNCEXPT not careful about MNCEXPT (noncommutative expt)

open
nobody
5
2006-08-24
2006-05-01
Robert Dodier
No

SIMPNCEXPT is not careful about simplifying ^^
(MNCEXPT, noncommutative exponent).

aa ^^ bb simplifies to aa ^ bb when aa is a scalar or
constant, (e.g. %e ^^ matrix => %e ^ matrix) but that's
not generally correct.

We can debate whether SIMPNCEXPT ought to go to the
expense of executing the matrix exponential code, but
if not that, then SIMPNCEXPT should at least return a
valid result.

Discussion

  • Barton Willis
    Barton Willis
    2006-05-02

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    user_id=895922

    In general, I suspect that both matrix exponential functions
    in Maxima have low accuracy for floating point matrices.
    Until we have better code for the float case, maybe this
    tips the argument in favor of returning a noun form.

    Barton

     
  • Robert Dodier
    Robert Dodier
    2006-08-24

    • labels: 460522 --> Lisp Core - Simplification