Implementation of the CIPSI algorithm in the Quantum Package

We want to calculate:

\begin{equation} \epsilon_{\rm PT2}(\mu)=\frac{\langle\Psi|\hat{H}|\mu\rangle^{2}}{E(\Psi)-\langle\mu|\hat{H}|\mu\rangle}\\ \end{equation}

1. The number of \(\mu\) scales formally as \({\cal O}(N_{\rm det}\times n_{\rm elec}^{2}\times n_{\rm virt}^{2})\)
2. We need to calculate \(\langle\mu|\hat{H}|\mu\rangle\) very fast
3. We need to calculate \(\langle\mu|\hat{H}|I\rangle\) very fast
4. The number of contributions \(\epsilon_{\rm PT2}\) scales as \(N_{\rm det}\) : PT2

1. Tri des determinants, mini/micro lists feuilles de pq etc
2. Sommations partielles, diagonale de Fock
3. Stockage des integrales dans le map_integrals + cache de 64^4 mos
4. Stochastic? Moller-Plesset partiel?