"Whit Armstrong" <[EMAIL PROTECTED]> writes:
> Is this a bug, or have I misunderstood the proper use of lm?
Dunno. It appears that logicals like factors are not supposed to have
matrix structure. What actually happens is that setting contrasts
strips dimension attributes
Browse[1]>
debug: for (nn in namD[isF]) if (is.null(attr(data[[nn]], "contrasts")))
contrasts(data[[nn]]) <- contr.funs[1 +
isOF[nn]]
Browse[1]> zz <- data[["y"]]
Browse[1]> contrasts(zz) <- contrasts(zz)
Browse[1]> zz
[1] TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE FALSE TRUE FALSE
[13] FALSE TRUE TRUE TRUE FALSE TRUE FALSE TRUE TRUE FALSE FALSE TRUE
[25] TRUE TRUE FALSE FALSE FALSE FALSE TRUE FALSE FALSE TRUE TRUE FALSE
[37] FALSE FALSE FALSE TRUE TRUE TRUE TRUE FALSE FALSE FALSE TRUE
..
[85] TRUE TRUE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE
[97] TRUE TRUE TRUE FALSE
Levels: FALSE TRUE
which in turn comes from
if (is.logical(x)) x <- factor(x, levels = c(FALSE, TRUE))
and the fact that factor() throws away dimensions.
*If* it's a bug, I don't think it is easily fixable....
> Thanks,
> Whit
>
>
> code:
> x <- rnorm(50)
> y <- matrix(as.logical(round(runif(100),0)),ncol=2)
> NROW(x)==NROW(y)
> lm(x~y)
>
>
>
> > x <- rnorm(50)
> > y <- matrix(as.logical(round(runif(100),0)),ncol=2)
> > NROW(x)==NROW(y)
> [1] TRUE
> > lm(x~y)
> Error in "[[<-.data.frame"(`*tmp*`, nn, value = c(2, 1, 2, 1, 1, 1, 2,
> :
> replacement has 100 rows, data has 50
> >
>
>
> However, the call to lm works if the matrix is a numeric instead of
> logical:
> x <- rnorm(50)
> y <- matrix(runif(100),ncol=2)
> NROW(x)==NROW(y)
> lm(x~y)
>
>
> Seems to be a problem in model.matrix.default:
>
> debug: for (nn in namD[isF]) if (is.null(attr(data[[nn]], "contrasts")))
> contrasts(data[[nn]]) <- contr.funs[1 +
> isOF[nn]]
> Browse[1]>
> Error in "[[<-.data.frame"(`*tmp*`, nn, value = c(1, 2, 2, 2, 2, 2, 2,
> :
> replacement has 100 rows, data has 50
> >
>
>
> > R.Version()
> $platform
> [1] "i686-pc-linux-gnu"
>
> $arch
> [1] "i686"
>
> $os
> [1] "linux-gnu"
>
> $system
> [1] "i686, linux-gnu"
>
> $status
> [1] "alpha"
>
> $major
> [1] "2"
>
> $minor
> [1] "2.0"
>
> $year
> [1] "2005"
>
> $month
> [1] "09"
>
> $day
> [1] "12"
>
> $"svn rev"
> [1] "35558"
>
> $language
> [1] "R"
>
> >
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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