gnu-octave / symbolic

A Symbolic Package for Octave using SymPy
https://octave.sourceforge.io/symbolic/
GNU General Public License v3.0
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`limit` of `diff` where `a` is a symbol #1308

Open vvavrychuk opened 1 month ago

vvavrychuk commented 1 month ago
>> syms f(x)
>> syms y
>> limit(diff(f),y)
error: Python exception: NotImplementedError: Don't know how to calculate the mrv of 'Subs(Derivative(f(_p), _p), _p, y + 1/_p)'
    occurred at line 10 of the Python code block:
    return _op(*_ins)
error: called from
    pycall_sympy__ at line 179 column 7
    elementwise_op at line 102 column 5
    limit at line 92 column 5

If limit approaches a constant, it is fine

>> limit(diff(f),0)
ans = (sym)

  / d        \|
  |---(f(xi))||
  \dxi       /|xi=0
vvavrychuk commented 2 weeks ago

opened upstream issue https://github.com/sympy/sympy/issues/27143