Error in re-building vignettes:
  ...
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.

 *** caught segfault ***
address b1b8d6d4, cause 'memory not mapped'

Traceback:
 1: qassert(empty.ok, "B1")
 2: checkSubset(x, choices, empty.ok, fmatch)
 3: assertSubset(c(vars, y), colnames(data), FALSE)
 4: permutationImportance(iris, "Sepal.Width", "Species", fit)
 5: eval(expr, envir, enclos)
 6: eval(expr, envir, enclos)
 7: withVisible(eval(expr, envir, enclos))
 8: withCallingHandlers(withVisible(eval(expr, envir, enclos)), warning = wHandler,     error = eHandler, message = mHandler)
 9: doTryCatch(return(expr), name, parentenv, handler)
10: tryCatchOne(expr, names, parentenv, handlers[[1L]])
11: tryCatchList(expr, classes, parentenv, handlers)
12: tryCatch(expr, error = function(e) {    call <- conditionCall(e)    if (!is.null(call)) {        if (identical(call[[1L]], quote(doTryCatch)))             call <- sys.call(-4L)        dcall <- deparse(call)[1L]        prefix <- paste("Error in", dcall, ": ")        LONG <- 75L        sm <- strsplit(conditionMessage(e), "\n")[[1L]]        w <- 14L + nchar(dcall, type = "w") + nchar(sm[1L], type = "w")        if (is.na(w))             w <- 14L + nchar(dcall, type = "b") + nchar(sm[1L],                 type = "b")        if (w > LONG)             prefix <- paste0(prefix, "\n  ")    }    else prefix <- "Error : "    msg <- paste0(prefix, conditionMessage(e), "\n")    .Internal(seterrmessage(msg[1L]))    if (!silent && isTRUE(getOption("show.error.messages"))) {        cat(msg, file = outFile)        .Internal(printDeferredWarnings())    }    invisible(structure(msg, class = "try-error", condition = e))})
13: try(f, silent = TRUE)
14: handle(ev <- withCallingHandlers(withVisible(eval(expr, envir,     enclos)), warning = wHandler, error = eHandler, message = mHandler))
15: timing_fn(handle(ev <- withCallingHandlers(withVisible(eval(expr,     envir, enclos)), warning = wHandler, error = eHandler, message = mHandler)))
16: evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos,     debug = debug, last = i == length(out), use_try = stop_on_error !=         2L, keep_warning = keep_warning, keep_message = keep_message,     output_handler = output_handler, include_timing = include_timing)
17: evaluate::evaluate(...)
18: evaluate(code, envir = env, new_device = FALSE, keep_warning = !isFALSE(options$warning),     keep_message = !isFALSE(options$message), stop_on_error = if (options$error &&         options$include) 0L else 2L, output_handler = knit_handlers(options$render,         options))
19: in_dir(input_dir(), evaluate(code, envir = env, new_device = FALSE,     keep_warning = !isFALSE(options$warning), keep_message = !isFALSE(options$message),     stop_on_error = if (options$error && options$include) 0L else 2L,     output_handler = knit_handlers(options$render, options)))
20: block_exec(params)
21: call_block(x)
22: process_group.block(group)
23: process_group(group)
24: withCallingHandlers(if (tangle) process_tangle(group) else process_group(group),     error = function(e) {        setwd(wd)        cat(res, sep = "\n", file = output %n% "")        message("Quitting from lines ", paste(current_lines(i),             collapse = "-"), " (", knit_concord$get("infile"),             ") ")    })
25: process_file(text, output)
26: knit(input, text = text, envir = envir, encoding = encoding,     quiet = quiet)
27: knit2html(..., force_v1 = TRUE)
28: (if (grepl("\\.[Rr]md$", file)) knit2html_v1 else if (grepl("\\.[Rr]rst$",     file)) knit2pandoc else knit)(file, encoding = encoding,     quiet = quiet, envir = globalenv(), ...)
29: vweave(...)
30: engine$weave(file, quiet = quiet, encoding = enc)
31: doTryCatch(return(expr), name, parentenv, handler)
32: tryCatchOne(expr, names, parentenv, handlers[[1L]])
33: tryCatchList(expr, classes, parentenv, handlers)
34: tryCatch({    engine$weave(file, quiet = quiet, encoding = enc)    setwd(startdir)    find_vignette_product(name, by = "weave", engine = engine)}, error = function(e) {    stop(gettextf("processing vignette '%s' failed with diagnostics:\n%s",         file, conditionMessage(e)), domain = NA, call. = FALSE)})
35: buildVignettes(dir = "/home/ripley/R/packages/tests32/mmpf.Rcheck/vign_test/mmpf")
An irrecoverable exception occurred. R is aborting now ...