Displaying 2 results from an estimated 2 matches for "nrti".
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crti
2011 Apr 20
3
[test message] Can R replicate this data manipulation in SAS?
...ricky data manipulation in SAS. Is there
any way to get the equivalent result in R?
Thanks,
Paul
**** SAS syntax for coding HAART in HIV patients;
**** Read in test data;
data haart;
input id book_class $ start_date :mmddyy. stop_date :mmddyy.;
format start_date stop_date mmddyy8.;
cards;
1004 NRTI 07/24/95 01/05/99
1004 NRTI 11/20/95 12/10/95
1004 NRTI 01/10/96 01/05/99
1004 PI 05/09/96 11/16/97
1004 NRTI 06/01/96 02/01/97
1004 NRTI 07/01/96 03/01/97
9999 PI 01/02/03 .
9999 NNRTI 04/05/06 07/08/09
;
run;
proc print data=haart;
run;
book_ start_ stop_
Ob...
2004 Sep 22
1
impenetrable warning
Dear R-help,
Can anyone explain the meaning of the warning,
Singular precision matrix in level -1, block 1
? Or how to track down where it comes from?
More precisely, using the nlme package, I'm issued with the warning
itt2 <- lme(lrna~rx.nrti+lbrna, random=~1|patid,
cor=corExp(form=~days|patid,nugget=T), weights=varPower(
form=~lbrna),data=rna3)
Warning messages:
1: Singular precision matrix in level -1, block 1
2: Singular precision matrix in level -1, block 1
the output is:
Linear mixed-effects model fit by REML
Data: rna3
Log-r...