The idea of estimating 7 parameters from 11 cases using mostly binary
variables just seems begging for a singular matrix.
On Sep 4, 2009, at 3:59 PM, Ping-Hsun Hsieh wrote:
Hi,
A error message arose while I was trying to fit a ordinal model with
lrm() I am using R 2.8 with Design package.
Here is a small set of mydata:
RC RS Sex CovA CovB CovC CovD CovE
2 1 0 1 1 0 -0.005575280 2
2 1 0 1 0 1 -0.001959580 2
3 0 0 0 1 0 -0.004725880 2
0 0 0 1 0 0 -0.005504850 2
2 1 1 0 0 0 -0.003880170 1
2 1 0 0 1 0 -0.006074230 2
2 1 0 0 1 1 -0.003963920 2
2 1 0 0 1 0 0.000658230 2
2 1 0 1 0 1 -0.002033610 2
0 0 0 0 0 1 -0.007761770 2
0 0 0 0 1 1 -0.000951784 2
Note: In the complete data, there are NAs. But the error messages
showed in both the complete and above sets.
attach(mydata)
lrm(RC~RS+Sex+CovA+CovB+CovC+CovD+CovE,data=mydata,na.action=na.pass)
singular information matrix in lrm.fit (rank= 8 ). Offending
variable(s):
CovE
Error in j:(j + params[i] - 1) : NA/NaN argument
detach(mydata)
lrm(mydata$RC~ mydata$RS+ mydata$Sex+ mydata$CovA+ mydata$CovB+
mydata$CovC+ mydata$CovD+ mydata$CovE,data=mydata,na.action=na.pass)
Error in if (!length(fname) || !any(fname == zname)) { :
missing value where TRUE/FALSE needed
I have debugged for a while, but no success. Does anyone know what
happens?
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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