Constraint parameter values (feature request)

[jacobq]

Is it possible to constraint the parameters? For example, I have some that cannot be less than 1. These could either be used as limits to "clamp" the values or they could be used as a termination condition similar to maxIterations.

If this isn't currently possible, would you accept a PR to add support for this? e.g. extend options to include a validators parameter equal to an array of functions that return true if the provided argument is a valid value for the corresponding parameter, otherwise returns false.

[maasencioh]

Hello @jacobq, first, all the PR are always welcomed, so go for it, and second, wouldn't be easier to use a Simplex if you know about the restrictions?

[jacobq]

I'm not familiar with what you're referring to. Is it the "simplex algorithm" in linear programming, the "downhill simplex method", or something else?

I wonder if I could achieve something similiar to constraints by modifying my target function to generate grossly large values when invalid (out of range) parameters are provided.

[m93a]

It seems that there already are options for that… 🤔 You can use options.maxValue = [100, 50, -3, …] to restrict the upper bound and options.minValue to restrict the lower bound similarly. It is however missing in the README, so we should close this after we add the documentation.

[jobo322]

hello there, you are just right, this option was implemented early, I am not sure if the name of those options isok

[m93a]

Maybe we should rename them to maxValues and minValues (with the s in the end) so that it's in accordance with initialValues.

[jacobq]

I came back to this today... @maasencioh I can't use the Simplex Algorithm because my function is non-linear. @m93a, Regarding existing options they are not present in the latest release -- only since https://github.com/mljs/levenberg-marquardt/commit/ad8e7507163e6978920c006418a65c8b6a48efa7 @jobo322 Thanks for adding support for min/max values. I agree that minValues and maxValues would be preferable (plural form).

Would someone be willing to publish a (beta?) version to NPM so that I can try it out? Update: Nevermind, I published @jacobq/ml-levenberg-marquardt, my own fork

[m93a]

I'm planing on finishing the PR later this month, then it can be published to NPM as a stable version, before that you'll have to use a fork.

PS: Did you know you can install a package directly from GitHub? That way you don't need to publish the fork to NPM, and still use it. 😉

[jacobq]

@m93a I'm aware of how to specify a git repository directly in package.json but in the past this didn't work with prepublish scripts so it only worked when there was no processing/compiling needed. I will look into it again as it sounds like now the prepare script may help with this.