Hi, All; When I was trying to convert the result object of hierarchical clustering into an instance of dendrogram class using as.dendrogram() and plot the resulting dendrogram horizontally, I got the following error message: [1] "evaluation nested too deeply: infinite recursion\ Options(expression=)?" Attr(,"class") [1] "try-error" This error happened while I was experimenting a function generating a composite plot of heatmap + dendrogram of gene clusters + dendrogram of sample clusters in microarray data analysis. The source chunk is a bit long but the part of origin for error is like this: ... hc <- hclust(mat, "single") ### THIS WORKED FINE! plot(hc, hang=-1) ### THIS ALSO WORKED FINE! IMAGE GENERATED ... dend <- as.dendrogram(hc) ### THIS SEEMS TO WORK FINE! plot(dend, horizontal=T, axes=F, ann=F, yaxs="i", leaflab="none") ### ERROR! ... 1. Can anyone suggest solutions? Actually this is first time I get this type of error message. 2. If converting hc to dendrogram class causes the trouble, is there anyone who can suggest a simple method of generating a dendrogram in horizontal direction not in vertical direction? Thanks in advance; Tae-Hoon Chung -------------------------------------------------- Tae-Hoon Chung Post-Doctoral Researcher Translational Genomics Research Institute (TGen) 445 N. 5th Street (Suite 530) Phoenix, AZ 85004 1-602-343-8724 (Direct) 1-480-323-9820 (Mobile) 1-602-343-8840 (Fax)