[Octave-bug-tracker] [bug #57614] quadgk integrates complex paths in reverse direction to specified "Waypoints"

[Rik]

URL:
  <https://savannah.gnu.org/bugs/?57614>

                 Summary: quadgk integrates complex paths in reverse direction
to specified "Waypoints"
                 Project: GNU Octave
            Submitted by: rik5
            Submitted on: Thu 16 Jan 2020 03:31:39 PM PST
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: Confirmed
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

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Details:

quadgk performs path integrals in reverse which results in a change of sign
for the output.

Sample integration


fun = @(z) exp(z)./z;
C = [1+i -1+i -1-i 1-i];
q2 = integral(fun,1,1,'Waypoints',C)
q2 = -9.8879e-17 - 6.2832e+00i


Exact result is


2*pi*i







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