Hi Claudio, I had a look at the code, and it looks that in dfs_search function, where the comment says that "BACTRACKING is happening HERE" there is something wrong (it looks neighbours are not all considered, because as you said next_node returns only one neighbour). I think that the definition of dfs_search (x:xs) l_closed is wrong. I'd start to write it from the beginning, instead of correcting this code. Cheers, Ut http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail Mail priva di virus. www.avg.com http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> Il giorno mer 21 ott 2020 alle ore 00:37 Claudio Cesar de Sa < ccs1664@gmail.com> ha scritto:
Hi everyone
Initially, I hope that this list is active yet. For some days, I had been trying to do a Depth First Search on a graph from scratch following something very didactical (clear, elegant - legible, any worry about efficiency).
This DFS keeps a boolean list to mark the nodes already visited and another with current or valid nodes ( the stack of DFS classic).
The code is naive and well documented and is here:
https://github.com/claudiosa/CCS/blob/master/haskell/dfs_graph.hs (excessively commented)
but unfortunately, it is not working. My guess is that the problem starts on *new_node* function. I am not sure if in DFS, when a current node gets a next neighbour to stack, it gets all the neighbours. In this code, it is getting one node per time.
The functions next_node and one_node seem very non-sense. Could someone help me?
Thanks in advance
claudio
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