Displaying 7 results from an estimated 7 matches for "kkt2".
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2011 Nov 29
2
Parameters setting in functions optimization
...orials :
optim(c(40,0.5), fn=LogLiketot)
>Error in 1 - ms : 'ms' is missing
But ms is 0.5 ...
So I've tried this form :
optimx(c(30,50),ms=c(0.4,0.5), fn=LogLiketot)
with different values for the two parameters :
par fvalues method fns grs itns conv KKT1
KKT2 xtimes
>2 19.27583, 25.37964 2249.698 BFGS 12 8 NULL 0 TRUE
TRUE 57.5
>1 29.6787861, 0.1580298 2248.972 Nelder-Mead 51 NA NULL 0 TRUE
TRUE 66.3
The first line is not possible but as I've not constrained the
optimization ... but the second line would be a ver...
2012 Apr 14
0
R-help: Censoring data (actually an optim issue
...I easily ran the code you supplied by changing optim to optimx in the penultimate
line. Here's the final output.
KKT condition testing
Number of parameters = 2
max abs gradient element = 0.004032794 test tol = 0.1018794
KKT1 result = TRUE
Hessian eigenvalues:
[1] 7.138974e+02 9.931285e-04
KKT2 result = TRUE
KKT results: gmax= 0.004032794 evratio= 1.391136e-06 KKT1 & 2: TRUE TRUE
[1] 7.138974e+02 9.931285e-04
Save results from method BFGS
> zz
method par fvalues fns grs hes rs conv KKT1 KKT2
2 BFGS 0.2832468, 52.6096161 100.8794 10 1 0 -2 3 TR...
2011 Aug 13
3
optimization problems
...he results are that
--------------------------------------------------------------------------------------------
> optimx(par=theta0, fn=obj.fy, method="BFGS", control=list(maxit=10000),
> hessian=T)
par fvalues method fns grs itns
conv KKT1 KKT2 xtimes
1 0.6, 1.6, 0.6, 1.6, 0.7 -0.02764405 BFGS 1 1 NULL 0 TRUE
NA 8.71
>
--------------------------------------------------------------------------------------------
Whenever I used different initial values, the initial ones are the answer of
OPTIMX(OPTIM).
Would you p...
2016 Oct 08
4
optim(…, method=‘L-BFGS-B’) stops with an error message while violating the lower bound
Hello:
The development version of Ecdat on R-Forge contains a vignette
in which optim(?, method=?L-BFGS-B?) stops with an error message while
violating the lower bound.
To see all the details, try the following:
install.packages("Ecdat", repos="http://R-Forge.R-project.org")
Then do "help(pac=Ecdat)" -> "User guides, package
2011 Aug 29
0
Error: Gradient function might be wrong ----- in OPTIMX
...uld not find anything wrong.
When I remove the gradient, I've got
-----------------------------------------------------------------
> optimx(par=theta0, fn=obj.fy, method="BFGS")
par fvalues method
fns grs itns conv KKT1 KKT2 xtimes
1 0.4423958, 0.9665069, 0.7920856, 1.1952092, 0.3083377 -0.01733672 BFGS
35 22 NULL 0 TRUE FALSE 76.02
-----------------------------------------------------------------
where the true theta is (0.5, 1.0, 0.8, 1.2, 0.6).
However, I've got better results below when I tried OP...
2011 May 18
1
Constrainted Nonlinear Optimization - lack of convergence
...ugmented
Lagrangian. Hence, I assume (perhaps incorrectly), that auglag is
automatically generating the dual problem, and attempts to find a solution
to the dual problem by calling 'optim'.
MY ISSUE:
The code often runs successfully (converges); sometimes with satisfying
(TRUE) KKT1 and KKT2, sometimes only 1 of the 2. Sometimes it fails to
converge at all. When it does converge, I do not obtain the same optimum
condition when I utilize different initial conditions. When it does fail to
converge, I often end up with a Nan, generated when attempting to take
log(f[i]), meaning that f[...
2011 Nov 10
3
optim seems to be finding a local minimum
Hello!
I am trying to create an R optimization routine for a task that's
currently being done using Excel (lots of tables, formulas, and
Solver).
However, otpim seems to be finding a local minimum.
Example data, functions, and comparison with the solution found in
Excel are below.
I am not experienced in optimizations so thanks a lot for your advice!
Dimitri
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