      psi(t,1) =   b(1,1) * exp( thetalog(t,1) * b(2,1) + 

     &             thetalog(t,2)*b(3,1)) 

      psi(t,2) =   b(1,2) * exp( thetalog(t,1) * b(2,2) + 

     &             thetalog(t,2)*b(3,2)) 

