[FIX]

louvain

-.stack-work/dist/x86_64-linux/Cabal-1.22.5.0/build/louvain/louvain
\ No newline at end of file

src/Data/Utils.hs

 module Data.Utils where
 
+import Data.Maybe 
 import Data.Graph.Inductive
 import Data.List (nub)
 
@@ -7,7 +8,7 @@ import Data.List (nub)
 label' :: (Graph gr) => gr a b -> Edge -> Maybe b
 label' gr (u,v) = lookup v (lsuc gr u)
 
-shortest_path :: (Real b, Graph gr) => gr a b -> Node -> Node -> Path
+shortest_path :: (Real b, Graph gr) => gr a b -> Node -> Node -> Maybe Path
 shortest_path graph node_1 node_2= sp node_1 node_2 graph
 
 

stack.yaml

 # This file was automatically generated by 'stack init'
-# 
+#
 # Some commonly used options have been documented as comments in this file.
 # For advanced use and comprehensive documentation of the format, please see:
-# http://docs.haskellstack.org/en/stable/yaml_configuration/
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
 
 # Resolver to choose a 'specific' stackage snapshot or a compiler version.
 # A snapshot resolver dictates the compiler version and the set of packages
 # to be used for project dependencies. For example:
-# 
+#
 # resolver: lts-3.5
 # resolver: nightly-2015-09-21
 # resolver: ghc-7.10.2
 # resolver: ghcjs-0.1.0_ghc-7.10.2
-# resolver:
-#  name: custom-snapshot
-#  location: "./custom-snapshot.yaml"
-resolver: lts-6.9
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-11.10
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.
-# 
+#
 # packages:
 # - some-directory
 # - https://example.com/foo/bar/baz-0.0.2.tar.gz
@@ -27,42 +30,36 @@ resolver: lts-6.9
 #    git: https://github.com/commercialhaskell/stack.git
 #    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
 # - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
-#   extra-dep: true
 #  subdirs:
 #  - auto-update
 #  - wai
-# 
-# A package marked 'extra-dep: true' will only be built if demanded by a
-# non-dependency (i.e. a user package), and its test suites and benchmarks
-# will not be run. This is useful for tweaking upstream packages.
 packages:
-- '.'
-- /home/alexandre/local/logiciels/haskell/graph/fgl
-
-  # Dependency packages to be pulled from upstream that are not in the resolver
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# using the same syntax as the packages field.
 # (e.g., acme-missiles-0.3)
-extra-deps: []
+# extra-deps: []
 
 # Override default flag values for local packages and extra-deps
-flags: {}
+# flags: {}
 
 # Extra package databases containing global packages
-extra-package-dbs: []
+# extra-package-dbs: []
 
 # Control whether we use the GHC we find on the path
 # system-ghc: true
-# 
+#
 # Require a specific version of stack, using version ranges
 # require-stack-version: -any # Default
-# require-stack-version: ">=1.1"
-# 
+# require-stack-version: ">=1.7"
+#
 # Override the architecture used by stack, especially useful on Windows
 # arch: i386
 # arch: x86_64
-# 
+#
 # Extra directories used by stack for building
 # extra-include-dirs: [/path/to/dir]
 # extra-lib-dirs: [/path/to/dir]
-# 
+#
 # Allow a newer minor version of GHC than the snapshot specifies
-# compiler-check: newer-minor
+# compiler-check: newer-minor
\ No newline at end of file