search for: meximum

Displaying 3 results from an estimated 3 matches for "meximum".

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2009 Dec 06
5
optim with constraints
Hi, dear R users I am a newbie in R and I wantto use the method of meximum likelihood to fit a Weibull distribution to my survival data. I use "optim" as follows: optim(c(1, 0.25),weibull.like,mydata=mydata,method="L-BFGS-B",hessian = TRUE) My question is: how do I setup the constraints so that the two parametrs of Weibull to be pisotive? Or should...
2009 Dec 06
2
MLE in R
Hi, dear R users I am a newbie in R and I need to use the method of meximum likelihood to fit a Weibull distribution to my survival data. I use "optim" as follows: optim(c(1.14,0.25),weibull.like,mydata=mydata,method="L-BFGS-B",hessian = TRUE) My question is: how do I setup the constraints that the two parametrs of Weibull to be pisotive? Many thank...
2007 Aug 14
1
Slack variable in OR
Hi dear R users, Is it basically correct that a problem is ( linearly on nonlinearly ) modeled so that the slack variable is bounded by an upper bound ? If so, how it can be handled and coded practically ? for example: x1+ x2 =< b so ----> x1 + x2 + s=b s=b- x1 - x2 b- x1 - x2 =< upper value But algorithms can not calculate b- x1 - x2 , because