Multivariate function roots

[falematte]

I don't find a way to calculate the roots of a 2d Approxfun. Is that possible?

[dlfivefifty]

That isn't supported at the moment. Note generally one wants either simultaneous roots of two functions or a curve of roots of a single function. The latter being challenging to say what kind of representation you want. (Chebfun does have a very nice but adhoc approach to this)

[falematte]

Thanks for the quick answer. Can you elaborate more about the ad hoc solution?

[dlfivefifty]

I don't know it but the code is here: https://github.com/chebfun/chebfun/blob/master/%40chebfun2v/roots.m

[falematte]

Is this working in approxfun too?

[dlfivefifty]

What do you mean? it's Matlab code

[falematte]

I was asking if we have an equivalent peace of code in julia here. Where I can find the status of 2d chebfuns in Approxfun? Thanks for the help! I would be also interested in examples for complex variable calculations such as those present on the chebfun site.

[dlfivefifty]

The 2D features implemented are generally demonstrated in the docs or examples, and we haven't implemented root finding. A PR adding this would be appreciated!

[falematte]

Can this become a feature request? :) Sadly I don't have the skills atm to do this on my own. I think a lot of people would be really interested anyway.

[dlfivefifty]

Who's going to implement the feature request?

[falematte]

In my projects I simply activate a tag "feature" on the issue and it become a "feature request". Is that possible?

[dlfivefifty]

Done! I guess my point is that I don't know if anyone with the right expertise has the time to add this feature, so unfortunately it won't likely be completed unless you do it yourself.

[falematte]

Thanks a lot! I understand your point. I love this project and find it very usefull! I hope someone will take care of this! I will also try to dig a little bit more to see what I can do!