Brian Beckman

Here is another dead link #+SETUPFILE: ~/.dotfiles/org/theme-readtheorg.setup

And another one: ** Using a custom theme :PROPERTIES: :ID: f6d1f139-2460-4844-93f1-c71277c810e0 :END: This is linked somewhere else in the file (you have to `org-toggle-link-display` to find the link target), but...

roger! It's still very useful (even though I can't run it :)

I believe that the bigger issue, here, is correct modeling of idempotent functions with a combination of `Flat` and `OneIdentiy` Idempotent functions have the behavior `eqv[eqv[p]]===eqv[p]===p`, e.g., `Times[Times[x]]===Times[x]===x`. https://reference.wolfram.com/language/ref/OneIdentity.html?view=all ....

Looks like mathics assumes `OneIdentity`. Let's consider Mathematica's built-in `Or`, first. Its relevant attributes are just `Flat, OneIdentity`: ``` In[97]:= Attributes[Or] Out[97]= {Flat, HoldAll, OneIdentity, Protected} ``` It also has...

Here is some more data about differences between Mathematica and mathics. Mathics has the correct pattern-matching behavior for `Times`, but doesn't let us mimic the behavior in our own symbol....

More data: ``` in both mathics and Mathematica, First[eqv[p, q, r]] === p Rest[eqv[p, q, r]] === eqv[q, r]] for all combinations of {Flat, Orderless, OneIdentity}. Proof: Generate all combinations...

I have some open questions on mathematica.stackexchange.com about this issue. https://mathematica.stackexchange.com/questions/183322/subtle-order-of-evaluation-issues-when-pattern-matching-with-attributes I regret that this became complicated, but I hope to get a much better understanding of the way pattern-matching...

I've started working on this again as of 11 Oct 2020. No ETA.

I've had good luck with Cholesky solvers in Eigen/C++ and LAPACKE/C (see around line 191 [in this gist](https://gist.github.com/rebcabin/5071aff8b55db7c99dd986566427cd78)). I think LAPACK doesn't even have a matrix inverse routine! If my...