[Octave-bug-tracker] [bug #56665] Incorrect results with ppval and interp1, with complex input

[Marco Caliari]

Follow-up Comment #1, bug #56665 (project octave):


pp = interp1([1 2], [2 4], 'pp')


is the polynomial p = @(x) 2*x and it is true that p(1.5+0.0i) should be
3+0.02i. But in a more general situation, pp is a piecewise polynomial
function. When you want to evaluate it at a target point xbar, then ppval has
to find the interval in which xbar lies and evaluate the corresponding
polynomial. How do you identify the interval if xbar in complex? The complex
step method works for analytical functions.

Matlab does not allow to evaluate pp at a complex point. I think octave should
not allow, too.

    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?56665>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/