Dear r-help, I ran output <- lm(formu, data=mydata) I want to look at the condition number (to see if the matrix is near singular). How? Also, I use the function stepAIC from MASS to select models, how can I see the condition numbers in each step? While I am at it. I find a minor bug: R 1.7.1 on window XP, when you copy and paste by click one button, then the input stopped, until you click the "copy and paste" button again and click OK. Thanks in advance. Mai Zhou mai at ms.uky.edu
Mai Zhou wrote:> > Dear r-help, > > I ran > > output <- lm(formu, data=mydata) > > I want to look at the condition number (to see if the matrix is near singular). How?kappa(output)> Also, I use the function stepAIC from MASS to select models, how can I see the condition numbers in each step?See the argument "keep" described in ?stepAIC So you can use something like stepAIC(. . . . ., keep = function(fit, AIC) kappa(fit))> While I am at it. I find a minor bug: > R 1.7.1 on window XP, when you copy and paste by click > one button, then the input stopped, until you click the > "copy and paste" button again and click OK.ALready fixed for R-1.8.0 (beta). Uwe Ligges> Thanks in advance. > > Mai Zhou > mai at ms.uky.edu > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
Uwe Ligges wrote:> > Mai Zhou wrote: > > > > Dear r-help, > > > > I ran > > > > output <- lm(formu, data=mydata) > > > > I want to look at the condition number (to see if the matrix is near singular). How? > > kappa(output) > > > > Also, I use the function stepAIC from MASS to select models, how can I see the condition numbers in each step? > > See the argument "keep" described in ?stepAIC > So you can use something like > > stepAIC(. . . . ., keep = function(fit, AIC) kappa(fit))Let me add: To print it also to the console, use: stepAIC(. . . . ., keep = function(x,y) {k <- kappa(x); cat("kappa =", k, "\n"); k}) Uwe Ligges> > > While I am at it. I find a minor bug: > > R 1.7.1 on window XP, when you copy and paste by click > > one button, then the input stopped, until you click the > > "copy and paste" button again and click OK. > > ALready fixed for R-1.8.0 (beta). > > Uwe Ligges > > > Thanks in advance. > > > > Mai Zhou > > mai at ms.uky.edu > > > > ______________________________________________ > > R-help at stat.math.ethz.ch mailing list > > https://www.stat.math.ethz.ch/mailman/listinfo/r-help