jeffjeffbear
Joined 1 year ago
Joined 1 year ago
Not quite, it means any submatrix taken from the upper(lower) part of the matrix has some low rank. Like a matrix is {3,4}-semiseperable if any sub matrix taken from the lower triangular part has at most rank 3 and any submatrix taken from the upper triangular part has at most rank 4.
The inverse of an upper bidiagonal matrix is {0,1}-semiseperable.
There are a lot of fast algorithms if you know a matrix is semiseperable.
edit: link https://people.cs.kuleuven.be/~raf.vandebril/homepage/public...
That's because it was an X11 thing, and everyone used X11.
Myself, I like to just allocate a too big block and shove everything into that then deal with indicies into that array if I care about performance. you can even flatten the tree in a way to get better locality if you care about that.
Does it? If I draw a naked stick figure with boobs and say it is 14, is that morally wrong? At what point should a person care? Their point is that a drawing doesn't hurt people right?
Basically using GPT-5 and being careful