[R] cor inside/outside a function has different output
I'm calculating correlations between two matrices
mat1 - matrix(sample(1:500,25), ncol = 5,
dimnames=list(paste(mat1row, 1:5, sep=),
paste(mat1col, 1:5, sep=)))
mat2 - matrix(sample(501:1000,25), ncol = 5,
dimnames=list(paste(mat2row, 1:5, sep=),
paste(mat2col, 1:5, sep=)))
using what would seem to be two similar methods:
Method 1:
f - function(x,y) cor(x,y)
apply(mat1, 1, f, y=mat2)
Method 2:
cor(mat1, mat2)
However, the results (see blow) are different:
apply(mat1, 1, f, y=mat2)
mat1row1 mat1row2mat1row3mat1row4mat1row5
[1,] -0.27601028 -0.1352143 0.03538690 -0.03084075 -0.60171704
[2,] -0.01595532 -0.3881197 -0.43663982 0.49081806 0.33291995
[3,] 0.35969624 -0.0582948 0.57462169 0.09926796 -0.02948423
[4,] -0.41435920 -0.7164638 -0.21213496 -0.55183934 -0.25341790
[5,] 0.33802803 0.5371508 0.05219095 0.83533575 0.17850291
cor(mat1, mat2)
mat2col1mat2col2 mat2col3 mat2col4 mat2col5
mat1col1 -0.84077496 -0.01538414 -0.6078933 -0.2263840 -0.1421335
mat1col2 0.23074421 0.54606286 -0.2354733 0.5214255 -0.2129077
mat1col3 -0.8528 0.19550100 -0.5920509 -0.8694040 0.6853990
mat1col4 0.08050976 -0.55449840 0.6225666 0.6187971 -0.8971584
mat1col5 -0.10199564 -0.43854767 -0.5803077 -0.5100285 0.2848351
Also, for method 2, the calculations are done on a column x column
basis. Is there any way to do this on a row by row basis. Looking at
the help page for cor, I don't see any parameters that could be used to
do this.
Thanks,
- Bruce
**
Please be aware that, notwithstanding the fact that the pers...{{dropped}}
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Re: [R] cor inside/outside a function has different output
Sorry. I looked up t after writing the previous email and realized that
was what I was looking for!
-Original Message-
From: Gabor Grothendieck [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 24, 2007 11:48 AM
To: Bernzweig, Bruce (Consultant)
Cc: r-help@stat.math.ethz.ch
Subject: Re: [R] cor inside/outside a function has different output
I think this is really answered already in my previous post but just in
case
try this:
res1 - t(apply(mat1, 1, cor, t(mat2)))
res2 - cor(t(mat1), t(mat2))
all.equal(res1, res2, check.attributes = FALSE)
[1] TRUE
On 7/24/07, Bernzweig, Bruce (Consultant) [EMAIL PROTECTED] wrote:
I'm calculating correlations between two matrices
mat1 - matrix(sample(1:500,25), ncol = 5,
dimnames=list(paste(mat1row, 1:5, sep=),
paste(mat1col, 1:5, sep=)))
mat2 - matrix(sample(501:1000,25), ncol = 5,
dimnames=list(paste(mat2row, 1:5, sep=),
paste(mat2col, 1:5, sep=)))
using what would seem to be two similar methods:
Method 1:
f - function(x,y) cor(x,y)
apply(mat1, 1, f, y=mat2)
Method 2:
cor(mat1, mat2)
However, the results (see blow) are different:
apply(mat1, 1, f, y=mat2)
mat1row1 mat1row2mat1row3mat1row4mat1row5
[1,] -0.27601028 -0.1352143 0.03538690 -0.03084075 -0.60171704
[2,] -0.01595532 -0.3881197 -0.43663982 0.49081806 0.33291995
[3,] 0.35969624 -0.0582948 0.57462169 0.09926796 -0.02948423
[4,] -0.41435920 -0.7164638 -0.21213496 -0.55183934 -0.25341790
[5,] 0.33802803 0.5371508 0.05219095 0.83533575 0.17850291
cor(mat1, mat2)
mat2col1mat2col2 mat2col3 mat2col4 mat2col5
mat1col1 -0.84077496 -0.01538414 -0.6078933 -0.2263840 -0.1421335
mat1col2 0.23074421 0.54606286 -0.2354733 0.5214255 -0.2129077
mat1col3 -0.8528 0.19550100 -0.5920509 -0.8694040 0.6853990
mat1col4 0.08050976 -0.55449840 0.6225666 0.6187971 -0.8971584
mat1col5 -0.10199564 -0.43854767 -0.5803077 -0.5100285 0.2848351
Also, for method 2, the calculations are done on a column x column
basis. Is there any way to do this on a row by row basis. Looking at
the help page for cor, I don't see any parameters that could be used
to
do this.
Thanks,
- Bruce
**
Please be aware that, notwithstanding the fact that the
pers...{{dropped}}
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
**
Please be aware that, notwithstanding the fact that the pers...{{dropped}}
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] cor inside/outside a function has different output
I think this is really answered already in my previous post but just in case
try this:
res1 - t(apply(mat1, 1, cor, t(mat2)))
res2 - cor(t(mat1), t(mat2))
all.equal(res1, res2, check.attributes = FALSE)
[1] TRUE
On 7/24/07, Bernzweig, Bruce (Consultant) [EMAIL PROTECTED] wrote:
I'm calculating correlations between two matrices
mat1 - matrix(sample(1:500,25), ncol = 5,
dimnames=list(paste(mat1row, 1:5, sep=),
paste(mat1col, 1:5, sep=)))
mat2 - matrix(sample(501:1000,25), ncol = 5,
dimnames=list(paste(mat2row, 1:5, sep=),
paste(mat2col, 1:5, sep=)))
using what would seem to be two similar methods:
Method 1:
f - function(x,y) cor(x,y)
apply(mat1, 1, f, y=mat2)
Method 2:
cor(mat1, mat2)
However, the results (see blow) are different:
apply(mat1, 1, f, y=mat2)
mat1row1 mat1row2mat1row3mat1row4mat1row5
[1,] -0.27601028 -0.1352143 0.03538690 -0.03084075 -0.60171704
[2,] -0.01595532 -0.3881197 -0.43663982 0.49081806 0.33291995
[3,] 0.35969624 -0.0582948 0.57462169 0.09926796 -0.02948423
[4,] -0.41435920 -0.7164638 -0.21213496 -0.55183934 -0.25341790
[5,] 0.33802803 0.5371508 0.05219095 0.83533575 0.17850291
cor(mat1, mat2)
mat2col1mat2col2 mat2col3 mat2col4 mat2col5
mat1col1 -0.84077496 -0.01538414 -0.6078933 -0.2263840 -0.1421335
mat1col2 0.23074421 0.54606286 -0.2354733 0.5214255 -0.2129077
mat1col3 -0.8528 0.19550100 -0.5920509 -0.8694040 0.6853990
mat1col4 0.08050976 -0.55449840 0.6225666 0.6187971 -0.8971584
mat1col5 -0.10199564 -0.43854767 -0.5803077 -0.5100285 0.2848351
Also, for method 2, the calculations are done on a column x column
basis. Is there any way to do this on a row by row basis. Looking at
the help page for cor, I don't see any parameters that could be used to
do this.
Thanks,
- Bruce
**
Please be aware that, notwithstanding the fact that the pers...{{dropped}}
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
