Bob Carpenter

> Found some more signatures we would probably like to support but that don't compile: Does the other order, `subtract(complex_matrix, complex)`, work?

> Like for test_grad_hessian in the docs the value to test is x, but x is always an Eigen::VectorXd. What is the path to parse complex inputs happening at? The...

I can't figure out what's going wrong with the FFT tests. They work for reverse mode, but have a bunch of failures in forward mode, including their use for Hessians,...

I'm not sure what's going on with the automation. I'd prefer to start new issues than modify old ones. you can ignore the chatter about FFTs as it's not really...

> @bob-carpenter thinks he might know why That's easy---it doesn't work because the vectorization code was commented out. I'll try to sort it out on the C++ side, but might...

Yes, @nikunj410, we should have general complex eigendecomposition in either the next release (2.30) or the one after. We just finished adding 1D and 2D FFTs and inverses for 2.30...

Hi, @tvrsimhan. That'd be great. We accept pull requests for issues. Please let us know if you have any questions about how to implement it or test it (questions on...

It should follow the other functions. That means a primitive (`double`) implementation in `stan/math/prim/fun` and then one with custom gradients in `stan/math/rev/fun`. The primitive version needs thorough testing, then the...

I'm heading out of town on vacation for a few days, so I won't be able to review until next Tuesday at the earliest.

I rewrote the issue as an issue and tagged it as a feature and good first issue, but it's still missing all the boilerplate. > Is it faster or negligibile...