C ELM1D               DESCRIBES BEAM AT PRESENT LOCATION
C
C SIT(6,6)     TEMPORARY SIGMA MATRIX, CALCULATED ONLY WHEN NEEDED.
C RECENT       TRUE IF SIT REPRESENTS THE CURRENT BEAM MATRIX.
C
      LOGICAL         RECENT
      REAL            SIT(6,6)
C
      COMMON /ELM1D/  SIT, RECENT