Failure in initial objective function evaluation. LSQCURVEFIT cannot continue.

t=0:20;
N=[3.9000    5.2000    7.2000    9.6000   12.9000   17.1000   23.2000   31.4000   38.6000   50.2000   62.9000   76.0000  92.6000  106.5000  123.2000  131.7000  150.7000  179.3000  204.0000  226.5000  251.4000]
x0=[300.0000    0.3000]
x = lsqcurvefit(@logistic,x0,t,N)
f=logistic(x,t);
plot(t,N,'.',t,f,'m')
xlabel(Year)
ylabel(Population)

[Walter Roberson]

On my system it stops, saying that logistic is not defined.

[Matt J]

You should not pass your objective function to lsqcurvefit until you have verified that it works.