# MAX_NUM_VECS

> Maximum number of Davidson subspace vectors which can be held on disk for the CI coefficient and sigma vectors. (There is one H(diag) vector and the number of D vectors is equal to the number of roots). When the number of vectors on disk reaches the value of MAX_NUM_VECS, the Davidson subspace will be collapsed to COLLAPSE_SIZE vectors for each root. This is very helpful for saving disk space. Defaults to MAXITER * NUM_ROOTS + NUM_INIT_VECS

> - Type: integer
> - Default: 0