fmincon query
in [Matlab]
|
From: Mithun Biswas on 5 May 2008 09:14 I am trying to understand how 'fmincon' works for my minimization problem from the printed output. Actually, fmincon prints some output and then exits giving error message. The output is like this : End diagnostic information 9 0.0000000000 2.71580405e-03 0.0000271580 11 0.0027158040 4.56840681e-03 0.0000456828 13 0.0072842109 2.71580405e-03 0.0000271560 9 0.0000000000 2.71580405e-03 0.0027158040 11 0.0027158040 4.56840681e-03 0.0045684056 13 0.0072842109 2.71580405e-03 0.0027158020 9 0.0000000000 2.71580000e-03 0.0000271580 11 0.0027158000 4.56840000e-03 0.0000456828 13 0.0072842000 2.71580000e-03 0.0000271560 9 0.0000000000 2.71580000e-03 0.0027157999 11 0.0027158000 4.56840000e-03 0.0045683988 13 0.0072842000 2.71580000e-03 0.0027157980 Iter F-count f(x) max constraint Step-size 0 3 9.99967e-05 67.99 Infeasible start point I think the first column give no. of iterations. But what are the second, third and fourth columns ?. Why does MATLAB print the same result four times ? What is F-count ? And lastly, why does x take some values which is out of range at the beginning of the next iteration ?
From: John D'Errico on 5 May 2008 09:47 In article <fvn18p$13v$1(a)fred.mathworks.com>, "Mithun Biswas" <mbiswas51(a)yahoo.co.uk> wrote: > I am trying to understand how 'fmincon' works for my > minimization problem from the printed output. Actually, > fmincon prints some output and then exits giving error > message. The output is like this : > > End diagnostic information > > 9 0.0000000000 2.71580405e-03 0.0000271580 > 11 0.0027158040 4.56840681e-03 0.0000456828 > 13 0.0072842109 2.71580405e-03 0.0000271560 > 9 0.0000000000 2.71580405e-03 0.0027158040 > 11 0.0027158040 4.56840681e-03 0.0045684056 > 13 0.0072842109 2.71580405e-03 0.0027158020 > 9 0.0000000000 2.71580000e-03 0.0000271580 > 11 0.0027158000 4.56840000e-03 0.0000456828 > 13 0.0072842000 2.71580000e-03 0.0000271560 > 9 0.0000000000 2.71580000e-03 0.0027157999 > 11 0.0027158000 4.56840000e-03 0.0045683988 > 13 0.0072842000 2.71580000e-03 0.0027157980 > > Iter F-count f(x) max constraint Step-size > 0 3 9.99967e-05 67.99 > Infeasible start point You starting point is not a valid one compared to the constraints. It is "infeasible". > I think the first column give no. of iterations. But what > are the second, third and fourth columns ?. Why does MATLAB > print the same result four times ? What is F-count ? And > lastly, why does x take some values which is out of range > at the beginning of the next iteration ? Fmincon saw that the initial point was infeasible. So it could not get beyond iteration zero. It took 3 function evaluations in that vicinity. f(x) is the function value at your starting value. Max constraint is the value of one of your constraints. It must not be positive. This is the most positive constraint error. John -- The best material model of a cat is another, or preferably the same, cat. A. Rosenblueth, Philosophy of Science, 1945 Those who can't laugh at themselves leave the job to others. Anonymous
From: Mithun Biswas on 6 May 2008 09:31 > It took 3 function evaluations in that > vicinity. OK, that probably means first and second column give x values, third fval for three function evaluations. Am I right ? What is the fourth column ? Why does MATLAB print it four times ? > You starting point is not a valid one > compared to the constraints. It is > "infeasible". So, I changed the constraint. Now MATLAB shows the 'infeasible start point' error for iteration 0 but continues and exits at a later stage. Iter F-count f(x) constraint Step deriv optim-Proced -> 0 3 0.00999983 0.988 -> 1 7 0 0.2592 1 -0.75 1.85e+04 -> 2 11 0 0.06086 1 -5.22e-16 24 ERROR ..... Can you explain this a little bit ? Mithun
|
Pages: 1 Prev: how to use combolist of vsFlexArray in GUI Next: fmincon query |