Error when trying to get domain for sqrt function

[JulienDamers]

I tried to implement a function that checks if a box belongs to the domain of a function.

Using the following code I noticed unexpected results with the square root function.

Function f("x","y","(sqrt(x+y))");
Interval y(0,0);
CtcFwdBwd ctc(f,y);

IntervalVector x(2);
x.init(Interval(-5,0));
ctc.contract(x);
cout << "x " << x << endl;

Output:

x ([-5, 0] ; [-5, 0])

The result I expected here was x (<0, 0> ; <0, 0>). Is there anything wrong in my test?

I tried with various values for the constraint y and here are the different outputs.

Test 1:

Interval y(0,ibex::next_float(0));

output

x (<-0, 0> ; <-0, 0>)

Test 2:

Interval y(ibex::next_float(0),ibex::next_float(0));

output

x empty vector

Test 3:

Interval y(ibex::previous_float(0),0);

output

x (<-0, 0> ; <-0, 0>)

Test 4:

Interval y(ibex::previous_float(0),ibex::previous_float(0));

output

x empty vector

[JulienDamers]

I forgot to mention, I am using ibex version 2.8.2.

[gchabert]

Yes, I never noticed that. Thanks for reporting the issue.
It will be fixed in the next release.
Gilles