a := 18; b := 2; c := 1; d := 1; f := 1; DEtools[phaseportrait]({diff(x(t), t) = a*x-b*exp(x)*y/(1+exp(x))-f*x*x, diff(y(t), t) = -c*y+b*exp(x)*d*y/(1+exp(x))}, [x(t), y(t)], t = 0 .. 100, {[x(0) = .1, y(0) = 18], [x(0) = .1, y(0) = 27], [x(0) = .2, y(0) = 28], [x(0) = .5, y(0) = 16], [x(0) = .6, y(0) = 14], [x(0) = .7, y(0) = 8], [x(0) = .7, y(0) = 29], [x(0) = 1.0, y(0) = 18], [x(0) = 1.0, y(0) = 22], [x(0) = 1.2, y(0) = 20], [x(0) = 1.5, y(0) = 20], [x(0) = 1.5, y(0) = 24.0], [x(0) = 1.6, y(0) = 26.0], [x(0) = 1.7, y(0) = 28], [x(0) = 1.8, y(0) = 21], [x(0) = 2.0, y(0) = 9], [x(0) = 2.0, y(0) = 28]}, x = 0 .. 2, y = 0 .. 30, dirgrid = [13, 13], stepsize = 0.5e-1, arrows = SLIM, axes = BOXED, thickness = 2)