:term:`CFOUR_FOCK <CFOUR_FOCK (CFOUR)>`
"""""""""""""""""""""""""""""""""""""""

      This option is used to control the algorithm used for construction of the Fock matrix in SCF calculations. PK (=0) uses the PK-supermatrix approach while AO (=1) constructs the matrix directly from the basis function integrals. In general, PK is somewhat faster, but results in considerable use of disk space when out-of-core algorithms are required. (Default: FOCK).

      * **Type**: string
      * **Possible Values**: PK, AO
      * **Default**: No Default

