Hi, thanks for the fast answers. I'm sorry, if I was not clear enough in my question. The problem we are trying to solve is LetterDisplay. There is already a heuristic implemented in the multcompView package of Hans-Peter Piepho. We implemented an exact fixed parameter tractable implementation for that problem (implementation in OCaml).
The new R function works similar like the original multcompLetters function. But instead of running the heuristic the input is forwarded to the OCaml program. Because the new multcompView function should have the same return format as the original one (users don't have to bother about the new implementation and still use the old code) the output then has to be formatted in the same way as it is done by now in multcompLetters. The output of the OCaml program is a file containing a matrix. Names that occur in the same row of the matrix are not significant different, so they should have a common letter in the LetterDisplay, i.e. each row in the matrix corresponds to one letter in the LetterDisplay. Right now those LetterDisplays are build up character by character like it was in the original function. But as you already mentioned storing for each name the characters as a list (i.e. a matrix with a row for each name and so many columns as lines in the output file) and then concatenating all at once probably will improve the performance already significantly. And runtime is in this case probably more critical than memory issues. I didn't use Rprof so far, but I will definitely try it. But just to get an idea of what the problem is: The input for a LetterDisplay can also be given as a graph. One of our test instances is a graph with 121 nodes and 5108 edges. The OCaml program needs ca. 1 second to compute the result. But then computing the LetterDisplays needs more than two hours ... Thanks a lot, T. Steijger ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
