SUBROUTINE INPBF
C     ================
C
      INCLUDE 'PARAMS.FOR'
      INCLUDE 'MODELP.FOR'
      PARAMETER (MINPUT=MLEVEL+4)
      DIMENSION DEPTH(MDEPTH),X(MINPUT,MDEPTH),XX(MDEPTH),BF(MDEPTH)
C
      OPEN(8,FILE='bfactors',STATUS='OLD')
      NUMLT=3
      IF(INMOD.EQ.2) NUMLT=4
      READ(8,*) NDPTH,NUMPAR
      READ(8,*) (DEPTH(I),I=1,NDPTH)
      IF(NUMPAR.LT.0) NUMLT=NUMLT+1
      NUMP=ABS(NUMPAR)
      DO ID=1,NDPTH
         READ(8,*) (X(I,ID),I=1,NUMP)
      END DO
      CLOSE(8)
c
c     interpolate the input b-factors to the original DM-scale;
c     compute new NLTE populations
c
      DO I=NUMLT+1,NUMP
         DO ID=1,NDPTH
            XX(ID)=X(I,ID)
         END DO
         CALL INTERP(DEPTH,XX,DM,BF,NDPTH,ND,2,1,1)
         DO ID=1,ND
            POPUL(I-NUMLT,ID)=POPUL(I-NUMLT,ID)*BF(ID)
         END DO
      END DO
C
      RETURN
      END