[BioC] issue with color coding heatmaps for positive and negative values

[Mark W Kimpel]

I would like to "hard code" the colors to be used with certain ranges of 
values for a heatmap. The issue has occurred because I have discovered 
than, in a special case of mine, positive numbers are not always yellow 
and negative numbers are not always blue. Below is an extreme example 
which demonstrates this behavior. The issue occurs regardless of whether 
scale="none" or scale="row" is used as an argument.

Is there a workaround such that I can use one scale for positive numbers 
and another scale for negatives?

Thanks,
Mark

a <- c(rep(c(-100, -9, -8, -11), 5), -2, 4)
a.mat <- matrix(rep(a, 50), byrow=TRUE, nrow=50)
require(RColorBrewer)
BlYl <- c('#0061FF', '#0A0780','#9D8F00', '#FFF200')
hmcol <- colorRampPalette(BlYl, space = "rgb")(128)
heatmap(a.mat, col=hmcol)
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Mark W. Kimpel MD  ** Neuroinformatics ** Dept. of Psychiatry
Indiana University School of Medicine

15032 Hunter Court, Westfield, IN  46074

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