Paying invoices sounds simple enough. A vendor creates an invoice and sends a bill, your team approves it, and the money goes out. In practice, though, invoice payments are where a lot of finance ...

It would be nice to know when a breakdown occurs in the lanczos method #463. At the moment it checks for convergence, but the method can suffer a breakdown whenever the two bi-orthogonal basis vectors ...

I would like to compute the single-particle Green's function and the single-particle excitation spectrum with the Lanczos method. I hope this functionality will be implemented in the future release.

Method acting and character acting are two approaches to developing a character. While they differ in technique and process, both require discipline and focus to achieve a successful performance. Here ...