[Octave-bug-tracker] [bug #33792] quadl fails for large integeration tolerances

[Marco Caliari]

Follow-up Comment #4, bug #33792 (project octave):

Dear Ben,

Matlab passes because it uses the *absolute* tolerance, whereas Octave the
relative. If you try


>> quadl(@(x) sin (2 + 3*x).^2, 0, 10, 0.3 * 7.6082)


where 7.6082 is the (quite bad) value used by Octave as magnitude estimate,
you get the same result 8.1963 in Matlab. In the Matlab help, it is written
that "QUAD may be most efficient for low accuracies": may we also add such a
warning in the help?

Now, among the four quadrature formulas quad, quadl, quadgk and quadcc there
are four different default values for the tolerances and three types of
absolute/relative choices of the tolerance. Isn't it confusing?

Best regards,

Marco

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