[Octave-bug-tracker] [bug #54934] [octave forge] (symbolic) jacobian

[Mike Miller]

Update of bug #54934 (project octave):

                Category:         Octave Function => Octave Forge Package   
                  Status:                    None => Need Info              
                 Release:                   4.2.2 => dev                    
                 Summary:          Using jacobian => [octave forge] (symbolic)
jacobian

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Follow-up Comment #1:

You haven't given jacobian a second argument to tell it what to take the
derivative with respect to. In this case, the function calls 'symvar' on your
input.

Since the input is simply an array of variables, symvar is a permutation of
those same variables:


>> symvar ([r, phi, theta])
ans = (sym) [φ  r  θ]  (1×3 matrix)
>> symvar ([r, theta, phi])
ans = (sym) [φ  r  θ]  (1×3 matrix)


So the jacobian is taken with respect to [phi, r, theta], at least on my
system with SymPy 1.3:


>> jacobian ([r, theta, phi], [phi, r, theta])
ans = (sym 3×3 matrix)

  ⎡0  1  0⎤
  ⎢       ⎥
  ⎢0  0  1⎥
  ⎢       ⎥
  ⎣1  0  0⎦



Does Matlab's 'jacobian' do something different in this case?

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