I want to make a heat map without row and column clustering to keep my row order as it is. It has ~8000genes. (Row 8206 column 14) My commands are for heatmap:

y <- read.csv ('inputdata.csv', row.names = 'Gene_Name', header = TRUE) 

hmcol <- colorRampPalette(brewer.pal(10,"RdBu"))(256)

heatmap(as.matrix(y),col=hmcol2,Rowv=NULL, Colv= NULL,margins =c(12,6))

It is working but even I have mentioned Rowv=NULL, Colv= NULL it is making clusters and reordering.

Any suggestion on how to stop reordering rows?

While I am using heatmap.2

y <- read.csv ('inputdata.csv', row.names = 'Gene_Name', header = TRUE) 

hmcol <- colorRampPalette(brewer.pal(10,"RdBu"))(256)

heatmap.2(as.matrix(y), Rowv=NULL, Colv= NULL, scale="row", density.info="none", trace="none",col=my_palette, margins =c(10,6)) 

It is working and does not cluster. It means here Rowv=NULL, Colv= NULL commands working But the problem is the script is running in low inputs (that is if I load around 2000 genes) but not running with the whole data sets(~8000 genes). Any suggestions will be highly appreciated.

Neither of these functions are from Bioconductor packages, so you should probably be asking at R-help (r-help@r-project.org), as they are from the stats and gplots packages (required and CRAN packages, respectively). In addition, how are we to know what 'but not running with the whole data sets' might mean? Do you get an error? What is it? Anyway if you post on R-help you need to be less mysterious.

If you want to use a Bioconductor package, you could consider ComplexHeatmap, which should have no problems with 8000 rows.