C(constraint, X) should return C(X)

[dpsanders]

Currently C(constraint, X) only returns the contracted box. But it calculates C.forward(X), i.e. the forward image under the function, as the first part of the process.

Given that it calculates this and this info is useful, it should return it.

[dpsanders]

(This would be a breaking change since code currently expects only one item to be returned, not two.)

[cvanaret]

Hi David,

I was about to post the same comment. It would be great to get the interval image of the function, so that we know:

• if the constraint was already satisfied
• therefore, if the contractor should be called in later iterations We can of course evaluate the function itself, but then we perform 2 evaluations. Based on your second message, I gather that this feature is not planned? Best,

Charlie

[dpsanders]

I'm planning to return C(X) in the new version of the package!