[R] Flipping a heatmap
maechler at stat.math.ethz.ch
Thu Sep 11 14:43:21 CEST 2003
>>>>> "AndyL" == Liaw, Andy <andy_liaw at merck.com>
>>>>> on Thu, 11 Sep 2003 07:46:16 -0400 writes:
AndyL> My feeling is that heatmap is not the right thing to
AndyL> use on a correlation matrix.
AndyL> The heatmap function expects a data matrix, and does
AndyL> a two-way clustering of cases and variables. It
AndyL> tries to rearrange the rows and columns so that
AndyL> similar colors are closer together. This obviously
AndyL> will not work for a correlation matrix. (The
AndyL> rearrangement is one of several enhancements that
AndyL> Robert/Martin added to my original attempt.)
AndyL> If you really want to do it, you may try to find my
AndyL> original naive version of the heatmap function, which
AndyL> I posted to the Bioconductor mailing list earlier
AndyL> this year. That does not do any rearragement.
Thank you, Andy.
Further note that the upcoming version of R will also allow the
option of *not* doing any reordering.
But even then, heatmap() is not quite appropriate for
>> -----Original Message-----
>> From: David Khabie-Zeitoune [mailto:dave at evocapital.com]
>> Sent: Thursday, September 11, 2003 4:04 AM
>> To: r-help at stat.math.ethz.ch
>> Subject: [R] Flipping a heatmap
>> I am using the heatmap function in package mva to look at
>> large correlation matrices visually. Is there any way to
>> "flip" the output of heatmap plot left-right so that, if
>> presented with a correlation matrix, it plots the unity
>> elements in the correlation matrix along a diagonal from top
>> left to bottom right?
>> For example:
>> x = matrix(rnorm(1000), ncol=10)
>> z = cor(x)
>> Heatmap calls image, and I've found ways to do it with image e.g:
>> will plot things the "right" way round, but
>> does not.
>> Any help much appreciated.
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