* NLP literature problem * Maranas and Floudas (1994) * Pseudo-ethane potential function * Parameters SCALAR th bond angle / 1.9111 /; SCALAR pi / 3.14159 /; SCALAR r bond distance / 1.54 /; VARIABLES t dihedral angle objval objective function variable; FREE VARIABLES objval; EQUATIONS f Objective function; f .. objval =e= 588600 / POWER(3*r**2-4*COS(th)*r**2-2*(POWER(SIN(th),2)*COS(t-2*pi/3)-POWER(COS(th),2))*r**2,6) - 1079.1 / POWER(3*r**2-4*COS(th)*r**2-2*(POWER(SIN(th),2)*COS(t-2*pi/3)-POWER(COS(th),2))*r**2,3) + 600800 / POWER(3*r**2-4*COS(th)*r**2-2*(POWER(SIN(th),2)*COS(t)-POWER(COS(th),2))*r**2,6) - 1071.5 / POWER(3*r**2-4*COS(th)*r**2-2*(POWER(SIN(th),2)*COS(t)-POWER(COS(th),2))*r**2,3) + 481300 / POWER(3*r**2-4*COS(th)*r**2-2*(POWER(SIN(th),2)*COS(t+2*pi/3)-POWER(COS(th),2))*r**2,6) -1064.6 / POWER(3*r**2-4*COS(th)*r**2-2*(POWER(SIN(th),2)*COS(t+2*pi/3)-POWER(COS(th),2))*r**2,3); * Bounds t.LO = 0; t.UP = 2*(pi); * Starting point (global solution) * t.L = 3.202; MODEL test /ALL/; SOLVE test USING NLP MINIMIZING objval;