Running examples in ‘zenplots-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: zenpath
> ### Title: (Group) Indices to Subset a Matrix for a Zenplot
> ### Aliases: zenpath extract_pairs connect_pairs graph_pairs group
> ### Keywords: utilities
> 
> ### ** Examples
> 
> ## A baby example to see how group() works
> A <- matrix(1:12, ncol = 3)
> lst <- list(1, list(2:3))
> group(A, indices = lst) # split the matrix according to the grouping given by lst
[[1]]
     [,1]
[1,]    1
[2,]    2
[3,]    3
[4,]    4

[[2]]
     [,1] [,2]
[1,]    5    9
[2,]    6   10
[3,]    7   11
[4,]    8   12

> 
> ## Some calls of zenpath()
> zenpath(10) # integer argument
 [1]  1  2  3  1  4  2  5  1  6  2  7  1  8  2  9  1 10  2  3  4  5  3  6  4  7
[26]  3  8  4  9  3 10  4  5  6  7  5  8  6  9  5 10  6  7  8  9  7 10  8  9 10
> ## Note that the result is of length 50 > 10 choose 2 as the underlying graph has to
> ## be even (and thus edges are added here)
> (zp <- zenpath(c(3, 5), method = "eulerian.cross")) # integer(2) argument
 [1] 1 4 2 5 1 6 2 7 1 8 3 4 3 6 7 3 5 8 2
> 
> ## Extract the first and last three pairs of indices
> extract_pairs(zp, n = 3)
[1] 1 4 2 5 3 5 8 2
> 
> ## A more sophisticated example
> nVars <- 5 # number of variables
> set.seed(271)
> x <- runif(nVars*(nVars-1)/2) # weights
> ## Construct the pairs
> pairs <- expand.grid(1:nVars, 1:nVars)[,2:1]
> pairs <- pairs[pairs[,1] < pairs[,2],]
> pairs <- matrix(unlist(pairs), ncol = ncol(pairs))
> stopifnot(length(x) == nrow(pairs)) # sanity check
> ## Manually compute the result of method = "strictly.weighted" and group the pairs
> ## 1) Sort pairs according to the weights x and plot the variables
> w <- order(x, decreasing = TRUE)
> (pairs. <- pairs[w,])
      [,1] [,2]
 [1,]    3    5
 [2,]    1    3
 [3,]    2    3
 [4,]    2    5
 [5,]    1    4
 [6,]    1    5
 [7,]    1    2
 [8,]    4    5
 [9,]    3    4
[10,]    2    4
> library(graph)
Loading required package: BiocGenerics
Loading required package: parallel

Attaching package: ‘BiocGenerics’

The following objects are masked from ‘package:parallel’:

    clusterApply, clusterApplyLB, clusterCall, clusterEvalQ,
    clusterExport, clusterMap, parApply, parCapply, parLapply,
    parLapplyLB, parRapply, parSapply, parSapplyLB

The following objects are masked from ‘package:stats’:

    IQR, mad, sd, var, xtabs

The following objects are masked from ‘package:base’:

    Filter, Find, Map, Position, Reduce, anyDuplicated, append,
    as.data.frame, basename, cbind, colMeans, colSums, colnames,
    dirname, do.call, duplicated, eval, evalq, get, grep, grepl,
    intersect, is.unsorted, lapply, lengths, mapply, match, mget,
    order, paste, pmax, pmax.int, pmin, pmin.int, rank, rbind,
    rowMeans, rowSums, rownames, sapply, setdiff, sort, table, tapply,
    union, unique, unsplit, which, which.max, which.min

> plot(graph_pairs(pairs.)) # depict all pairs (edge = pair)
Error: package required but not installed: ‘Rgraphviz’
Execution halted