Dear useRs,

Below a small chunk of code to illustrate an issue with generating heatmaps using the Heatmap function within the ComplexHeatmap package.

# this works fine, a pdf file gets generated and can be opened:

       dat <- matrix(rnorm(200), 10)
       pdf("heatmap.pdf", width = 15, height = 5)
       Heatmap(dat)
       dev.off()

# a for loop around also generates files (from the code below just 1)

for (i in 1){
       dat <- matrix(rnorm(200), 10)
       pdf(paste0("heatmap", i, ".pdf"), width = 15, height = 5)
       Heatmap(dat)
       dev.off()
}

# However, trying to open the file results in this error message in Acrobar reader (Version 10.1.8): “The file cannot be opened because it has no pages”

# a for loop around the heatmap.2 function from the gplots library works fine (but adjusting the plot is less flexible)

library(gplots)
for (i in 1)
        dat <- matrix(rnorm(200), 10)
       pdf(paste0("heatmap", i, ".pdf"), width = 15, height = 5)
       heatmap.2(dat)
       dev.off()
}

It would be very nice if someone knows a work around.
Thanks a lot in advance!

Best regards,
An

>sessionInfo()

R version 3.2.2 (2015-08-14)

Platform: x86_64-pc-linux-gnu (64-bit)

locale:

[1] C

attached base packages:

[1] grid      stats     graphics  grDevices utils     datasets  methods 

[8] base    

other attached packages:

[1] gplots_2.17.0        ComplexHeatmap_1.6.0 rj_2.0.4-2         

loaded via a namespace (and not attached):

[1] rj.gd_2.0.0-1       circlize_0.3.4      dendextend_1.1.8  

 [4] gtools_3.5.0        bitops_1.0-6        magrittr_1.5      

 [7] KernSmooth_2.23-15  GlobalOptions_0.0.8 gdata_2.17.0      

[10] whisker_0.3-2       GetoptLong_0.1.1    RColorBrewer_1.1-2

[13] rjson_0.2.15        tools_3.2.2         colorspace_1.2-6  

[16] caTools_1.17.1      shape_1.4.2       

The ComplexHeatmap package uses grid graphics, and it is often the case that you need to print your Heatmap output for it to show up in the pdf.

for (i in 1){
       dat <- matrix(rnorm(200), 10)
       pdf(paste0("heatmap", i, ".pdf"), width = 15, height = 5)
       print(Heatmap(dat))
       dev.off()
}