source/wham/src-restraints/icant.f

   1       INTEGER FUNCTION ICANT(I,J)
   2       IF (I.GE.J) THEN
   3         ICANT=(I*(I-1))/2+J
   4       ELSE
   5         ICANT=(J*(J-1))/2+I
   6       ENDIF
   7       RETURN
   8       END
   9