r - Lower triangle correlation heatmap -

i'm trying produce lower triangle heatmap of pairwise correlations in r.

here's data:

set.seed(1) mat <- matrix(rnorm(6*10),ncol=6,nrow=10) colnames(mat) <- c("s.-.+.1","s.-.+.2","s.-.+.3","s.+.-.1","s.+.-.2","s.+.-.3") 

here's code i'm trying:

getuppertri <- function(cor.mat){   cor.mat[lower.tri(cor.mat)] <- na   return(cor.mat) }  reordercormat <- function(cor.mat){   dist.mat <- as.dist((1-cor.mat)/2)   hc <- hclust(dist.mat)   cor.mat <-cor.mat[hc$order,hc$order] } cor.df <- reshape2::melt(getuppertri(reordercormat(cor(mat))),na.rm=true,value.name="correlation",varnames=c("sample1","sample2")) 

and ggplot heatmap code is:

require(ggplot2) ggplot(cor.mat.df,aes(sample2,sample1,fill=correlation))+geom_tile(color="white")+scale_fill_gradient2(low="blue",high="red",mid="white",midpoint=0,limit=c(-1,1),space="lab",name="pearson\ncorrelation")+theme_bw()+theme(axis.text.x=element_text(angle=45,vjust=1,size=10,hjust=1))+coord_fixed()+labs(x="",y="") 

which gives me:

so colored elements scattered on rather being confined lower triangle.

any idea what's problem?

well, reproduced script , plot

just change

ggplot(cor.mat.df ,aes(sample2, sample1, fill=correlation))+   geom_tile(color="white")+   scale_fill_gradient2(low="blue", high="red", mid="white", midpoint=0, limit=c(-1,1), space="lab", name="pearson\ncorrelation")+   theme_bw()+   theme(axis.text.x=element_text(angle=45,vjust=1,size=10,hjust=1))+   coord_fixed()+   labs(x="",y="") 

by

ggplot(cor.df, aes(sample2, sample1, fill=correlation))+   geom_tile(color="white")+   scale_fill_gradient2(low="blue", high="red", mid="white", midpoint=0, limit=c(-1,1), space="lab", name="pearson\ncorrelation")+   theme_bw()+   theme(axis.text.x=element_text(angle=45, vjust=1, size=10, hjust=1))+   coord_fixed()+   labs(x="",y="") 

my sessioninfo:

r version 3.3.2 (2016-10-31) platform: x86_64-w64-mingw32/x64 (64-bit) running under: windows 7 x64 (build 7601) service pack 1  locale: [1] lc_collate=spanish_colombia.1252  lc_ctype=spanish_colombia.1252    [3] lc_monetary=spanish_colombia.1252 lc_numeric=c                      [5] lc_time=spanish_colombia.1252      attached base packages: [1] stats     graphics  grdevices utils     datasets  methods   base       other attached packages: [1] ggplot2_2.2.1  loaded via namespace (and not attached):  [1] rcpp_0.12.8      digest_0.6.11    assertthat_0.1   grid_3.3.2       plyr_1.8.4        [6] gtable_0.2.0     magrittr_1.5     scales_0.4.1     stringi_1.1.2    reshape2_1.4.2   [11] lazyeval_0.2.0   labeling_0.3     tools_3.3.2      stringr_1.1.0    munsell_0.4.3    [16] colorspace_1.3-2 tibble_1.2