clear; clf;
theta=2/3;
thetac=1.0;
nx=128;
x=linspace(-1,1,nx);
F=0.5*theta*((1+x).*log((1+x)/2)+(1-x).*log((1-x)/2))+0.5*thetac*(1-x.^2);
plot(x,F,'k','linewidth',1.5);
axis([-1 1 1.05*min(F) 1.5*max(F)])
text('Interpreter','latex','String','$$ \phi $$','Position',[0.75 -0.0475],'fontsize',17);
text('Interpreter','latex','String','$$ F(\phi) $$','Position',[-1.25 0.05],'fontsize',17);
set(gca,'fontsize',17)
set(gcf,'PaperPositionMode','auto')