a****f
发帖数: 944 | 1 When you do energy minimization problems, do you use built-in matlab
function or write your own gradient descent method ( or other methods)?
I use matlab function fmincon for a constrained optimization problem, but
the parameters don't change at all after optimization, except those that did
not satisfy the constraints are changed to meet the constraints.
Does anyone know the reason? |
l*****i
发帖数: 3929 | 2 你要是不把问题描述得更详细一些，恐怕没人能给你任何建议...
did
【在 a****f 的大作中提到】
: When you do energy minimization problems, do you use built-in matlab
: function or write your own gradient descent method ( or other methods)?
: I use matlab function fmincon for a constrained optimization problem, but
: the parameters don't change at all after optimization, except those that did
: not satisfy the constraints are changed to meet the constraints.
: Does anyone know the reason?
|
j**u
发帖数: 6059 | 3 matlab的优化做的其实挺好的，你可能需要仔细看看manual。
did
【在 a****f 的大作中提到】
: When you do energy minimization problems, do you use built-in matlab
: function or write your own gradient descent method ( or other methods)?
: I use matlab function fmincon for a constrained optimization problem, but
: the parameters don't change at all after optimization, except those that did
: not satisfy the constraints are changed to meet the constraints.
: Does anyone know the reason?
|
a****f
发帖数: 944 | 4 I want to minimize the energy E=f(p;...). p is a vector containing a set of
parameters.
I set initial values of each element in p based on some prior knowledge.
Then I use fmincon to find the optimal p that minimizes E.
Some elements in p are constrained in a range so I set the constraints
according to the syntax of fmincon.
The result is, the elements in p without constraints do not change (the same
as initial values), the elements that are initially in their constraints do
not change either, o
【在 l*****i 的大作中提到】
: 你要是不把问题描述得更详细一些，恐怕没人能给你任何建议...
:
: did
|
l*****i
发帖数: 3929 | 5 More likely your own problem than fmincon. You should read the help document
s very carefully.
Or, set display='iter' in fmincon options and see what's happening.
of
same
do
some
【在 a****f 的大作中提到】
: I want to minimize the energy E=f(p;...). p is a vector containing a set of
: parameters.
: I set initial values of each element in p based on some prior knowledge.
: Then I use fmincon to find the optimal p that minimizes E.
: Some elements in p are constrained in a range so I set the constraints
: according to the syntax of fmincon.
: The result is, the elements in p without constraints do not change (the same
: as initial values), the elements that are initially in their constraints do
: not change either, o
|
a****f
发帖数: 944 | 6 Thank you.
I tried and it only ran 2 iterations before it was terminated. The 'max
constraint' value was -6.9 in both iterations. directional derivative and
first-order optimality are both 0. Is this normal?
What does max constraint mean? should it be close to 0 at the final
iteration? I used inequality constraint, something like Ax
document
【在 l*****i 的大作中提到】
: More likely your own problem than fmincon. You should read the help document
: s very carefully.
: Or, set display='iter' in fmincon options and see what's happening.
:
: of
: same
: do
: some
|
