News for hackers. Stuff that matters.
Re:The quest to evolve neural networks through evolutionary ... by randomsearch on Monday October 30, 2017 @03:00AM (#15583479)
> I have always seen evolutionary algorithm as a version of gradient descent... which is extremely wasteful

Evolutionary algorithms work by sampling a combinatorial solution space, and learning about the interactions between solution components. This is made explicit (and much more elegant) in the definition of EDAs:

https://en.wikipedia.org/wiki/Estimation_of_distribution_alg...

By contrast, gradient descent makes the assumption that such interaction effects don't exist or don't matter, which doesn't work for most optimisation problems - you get stuck in local optima.

Re:The quest to evolve neural networks through evolutionary ... by halflings on Wednesday November 01, 2017 @11:22PM (#15607585)
Thanks! That link was really helpful. I guess some optimisation methods using a Hessian take those interaction effects into consideration, but they are too expensive and not used in practice.

> doesn't work for most optimisation problems - you get stuck in local optima.

This bit is not necessarily true. In practice, and given the high dimensionality, it is (apparently) quite hard to get stuck in local optima. [0]

[0] https://www.quora.com/How-come-neural-networks-dont-get-stuc...

Re:The quest to evolve neural networks through evolutionary ... by randomsearch on Thursday November 02, 2017 @02:19PM (#15612856)
> This bit is not necessarily true. In practice, and given the high dimensionality, it is (apparently) quite hard to get stuck in local optima. [0]

In almost every optimisation problem I've encountered in practice, you do get stuck in local optima using simple techniques like SGD. Interaction effects are everywhere, and create local optima.

Re:The quest to evolve neural networks through evolutionary ... by rdlecler1 on Monday October 30, 2017 @12:15PM (#15586183)
Evolutionary algorithms may also let you evolve the architecture. Think of a fly brain evolving into a human brain using the same genetic toolbox. With learning algorithms your assuming a fixed architecture. Hard to think how we’d get open ended evolutionary AI without evolutionary algorithms. At that point learning algorithms is the context dependent optimization step after neurogenesis.
Re:The quest to evolve neural networks through evolutionary ... by halflings on Wednesday November 01, 2017 @11:20PM (#15607574)
The terms you are using are too vague, and seem disconnected from the reality of these algorithms.

How do evolutionary algorithms let you evolve the architecture? You define a model space, and explore it stochastically (with different evolutionary strategies). The model space you are exploring is linked to a specific architecture.

Regardless, there's also efforts in Deep Learning to automatically learn optimal network architectures ("AutoML").

Re:The quest to evolve neural networks through evolutionary ... by eru on Monday October 30, 2017 @09:02AM (#15584673)
Of course you can mix your gradient descent with simulated annealing. But that gets close to evolutionary algorithms.