[Scilab-users] How to fix the round off error of "intg"

[fujimoto2005]

My objective is to find a variable x which set the derivative of the function
f (x) with respect to x to zero.
The function f (x) is the integration of g(x, z) from a to b with respect to
z., that is,
f (x) = ∫g(x, z) dz over  (a, b).
The function g (x, z) is a well-behaved function that has one peak with
respect to z.
I used "intg" to calculate ∫g(x, z)dz.
I used  "numuderivatibe" to calculate f '(x)
I used   "fsoleve" to find x where f '(x) = 0.

When executed it, it stopped with the following warning.

"fsolve: numderivative: Error while evaluating the function: "intg: Error:
Round-off error detected, the requested tolerance (or default) cannot be
achieved. Try using bigger tolerances."

I would like to ask two questions.
1. Can I investigate the cause of rounding error by adding "disp" line in
macros "numderivative" or "intg" in order to monitor the variables?
2. Where can I modify to increase the tolerances of "intg"?

Thank you.



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