      Subroutine pimix (bn,bnf,t,tx)
      Implicit  Real*8   (a-h,o-z)
c *** see RH Landau, Program lpott, 1981
      Dimension bn(16), bnf(16), t(14), tx(14)
c     form partial wave decomp of pi+p,pi+n amplit udes
c     -non-flip, sp,sp,pp,pn,...
c     code for bn, bnf, bnuc, bnucf
c     all for pi plus, reaarange for pi minus latter
c     1 res,p 2 imsp    3 res,n        4 imsn
c     5 rep,p 6imp,p    7 rep,n        8 imp,n
c     9 red,p 10imd,p   11 red,n       12 imd,n
c     13 ref,p          14 imf,p       15 ref,n  16 imf,n
c     17 reg,p          18 img,p       19 reg,n  20 img,n
      rhl = 2./3.
      bn(1) = t(1)
      bn(2) = tx(1)
      bn(3) = bn(1)/3.+rhl*t(4)
      bn(4) = bn(2)/3.+rhl*tx(4)
      bn(5) = t(2)+2.*t(3)
      bn(6) = tx(2)+2.*tx(3)
      bn(7) = bn(5)/3.+rhl*(t(5)+2.*t(6))
      bn(8) = bn(6)/3.+rhl*(tx(5)+2.*tx(6))
      bn(9) = 2.*t(7)+3.*t(8)
      bn(10) = 2.*tx(7)+3.*tx(8)
      bn(11) = bn(9)/3.+rhl*(2.*t(11)+3.*t(12))
      bn(12) = bn(10)/3.+rhl*(2.*tx(11)+3.*tx(12))
      bn(13) = 3.*t(9)+4.*t(10)
      bn(14) = 3.*tx(9)+4.*tx(10)
      bn(15) = bn(13)/3.+rhl*(3.*t(13)+4.*t(14))
      bn(16) = bn(14)/3.+rhl*(3.*tx(13)+4.*tx(14))
c     spon flip,same order as above
      bnf(1) = 0.
      bnf(2) = 0.
      bnf(3) = 0.
      bnf(4) = 0.
      bnf(5) = t(3)-t(2)
      bnf(6) = tx(3)-tx(2)
      bnf(7) = bnf(5)/3.+rhl*(t(6)-t(5))
      bnf(8) = bnf(6)/3.+rhl*(tx(6)-tx(5))
      bnf(9) = t(8)-t(7)
      bnf(10) = tx(8)-tx(7)
      bnf(11) = bnf(9)/3.+rhl*(t(12)-t(11))
      bnf(12) = bnf(10)/3.+rhl*(tx(12)-tx(11))
      bnf(13) = t(10)-t(9)
      bnf(14) = tx(10)-tx(9)
      bnf(15) = bnf(13)/3.+rhl*(t(14)-t(13))
      bnf(16) = bnf(14)/3.+rhl*(tx(14)-tx(13))
      Return
      End
