NAME

     clag − Lagrangian Program written in C.

DESCRIPTION

     The  program  clag  forms the lagrangian matrix from the one
     and two particle density matrices and the one and two  elec‐
     tron  integrals.   The  lagrangian  is used for MCSCF and CI
     derivative calculations.

REFERENCES

     Lagrangian:

     1.   A New Dimension to Quantum Chemistry, Y. Yamaguchi,  Y.
          Osamura, J.D. Goddard, H. F. Schaefer III, Oxford Univ.
          Press, (1994).

FILES REQUIRED

          input.dat                Input file
          FILE71                   Transformed one‐electron integrals
          FILE72                   Transformed two‐electron integrals
          FILE73                   One‐Particle Density Matrix
          FILE74                   Two‐Particle Density Matrix

FILES UPDATED

          FILE75   Lagrangian
          output.dat

INPUT FORMAT

     The  input for this program is read from the file input.dat.
     The following keywords are valid:

     PRINT = integer
          This option determines the verbosity of the output.   A
          value  of  0 prints nothing, a value of 1 prints calcu‐
          lated ci energy and the various components  of  the  ci
          energy,  a  value of 2 prints the one‐ and two‐electron
          contributions to the MO lagrangian as well  as  the  MO
          lagrangian,  a  value of 3 prints the one‐particle den‐
          sity matrix, and a value of 4 prints  the  two‐particle
          density  matrix.   Do not use print = 4 unless the test
          case is very small.

     WRITE_CAS_FILES = boolean
          If TRUE, then write out the following files in  canoni‐
          cal  form  (p>=q,  r>=s,  pq>=rs) in Pitzer order: one‐
          electron  integrals  (file81),  two‐electron  integrals
          (file82),  one‐particle  density  matrix (file83), two‐
          particle density matrix (file84), lagrangian  (file85).
          This  is  temporary  and  is intended to aid in linking
          DETCI with CASSCF.