diff --git a/Data/Graph/Generators/Regular.hs b/Data/Graph/Generators/Regular.hs new file mode 100644 --- /dev/null +++ b/Data/Graph/Generators/Regular.hs @@ -0,0 +1,143 @@ +{-# LANGUAGE Safe #-} + +{- + Graph generators for simple parametric, regular graphs. + + Built using NetworkX 1.8.1, see +-} +module Data.Graph.Generators.Regular ( + completeGraph, + completeGraphWithSelfloops, + completeBipartiteGraph, + emptyGraph, + barbellGraph, + generalizedBarbellGraph, + cycleGraph, + lineGraph + ) where + +import Data.Graph.Generators + +{- + Generate a completely connected graph with n nodes. + + The generated graph contains node labels [0..n-1] + + In contrast to 'completeGraphWithSelfloops' this function + does not generate self-loops. + + Contains only one edge between two connected nodes, + use 'Data.Graph.Inductive.Basic.undir' to make it + quasi-undirected. The generated edge (i,j) satisfied @i < j@. +-} +completeGraph :: Int -- ^ The number of nodes in the graph + -> GraphInfo -- ^ The resulting complete graph +completeGraph n = + let allNodes = [0..n-1] + allEdges = [(i,j) | i <- allNodes,j <- allNodes, i < j] + in GraphInfo n allEdges + +{- + Variant of 'completeGraph' generating self-loops. + + The generated edge (i,j) satisfied @i <= j@. + + See 'completeGraph' for a more detailed behaviour description +-} +completeGraphWithSelfloops :: Int -- ^ The number of nodes in the graph + -> GraphInfo -- ^ The resulting complete graph +completeGraphWithSelfloops n = + let allNodes = [0..n-1] + allEdges = [(i, j) | i <- allNodes, j <- allNodes, i <= j] + in GraphInfo n allEdges + +{- + Generate the complete bipartite graph with n1 nodes in + the first partition and n2 nodes in the second partition. + + Each node in the first partition is connected to each node + in the second partition. + + The first partition nodes are identified by [0..n1-1] + while the nodes in the second partition are identified + by [n1..n1+n2-1] + + Use 'Data.Graph.Inductive.Basic.undir' to also add edges + from the second partition to the first partition. +-} +completeBipartiteGraph :: Int -- ^ The number of nodes in the first partition + -> Int -- ^ The number of nodes in the second partition + -> GraphInfo -- ^ The resulting graph +completeBipartiteGraph n1 n2 = + let nodesP1 = [0..n1-1] + nodesP2 = [n1..n1+n2-1] + allEdges = [(i, j) | i <- nodesP1, j <- nodesP2] + in GraphInfo (n1+n2) allEdges + +{- + Generates the empty graph with n nodes and zero edges. + + The nodes are labelled [0..n-1] +-} +emptyGraph :: Int -> GraphInfo +emptyGraph n = GraphInfo n [] + +{- + Generate the barbell graph, consisting of two complete subgraphs + connected by a single path. + + In contrast to 'generalizedBarbellGraph', this function always + generates identically-sized bells. Therefore this is a special + case of 'generalizedBarbellGraph' +-} +barbellGraph :: Int -- ^ The number of nodes in the complete bells + -> Int -- ^ The number of nodes in the path, + -- i.e the number of nodes outside the bells + -> GraphInfo -- ^ The resulting barbell graph +barbellGraph n np = generalizedBarbellGraph n np n + +{- + Generate the barbell graph, consisting of two complete subgraphs + connected by a single path. + + Self-loops are not generated. + + The nodes in the first bell are identified by [0..n1-1] + The nodes in the path are identified by [n1..n1+np-1] + The nodes in the second bell are identified by [n1+np..n1+np+n2-1] + + The path only contains edges +-} +generalizedBarbellGraph :: Int -- ^ The number of nodes in the first bell + -> Int -- ^ The number of nodes in the path, i.e. + -- the number of nodes outside the bells + -> Int -- ^ The number of nodes in the second bell + -> GraphInfo -- ^ The resulting barbell graph +generalizedBarbellGraph n1 np n2 = + let nodesP1 = [0..n1-1] + nodesPath = [n1..n1+np-1] + nodesP2 = [n1+np..n1+np+n2-1] + edgesP1 = [(i, j) | i <- nodesP1, j <- nodesP1, i /= 2] + edgesPath = [(i, i+1) | i <- [n1+np..n1+np+n2]] + edgesP2 = [(i, j) | i <- nodesP2, j <- nodesP2] + in GraphInfo (n1+np+n2) (edgesP1 ++ edgesPath ++ edgesP2) + +{- + Generate the cycle graph of size n. + + Edges are created from lower node IDs to higher node IDs. +-} +cycleGraph :: Int -- ^ n: Number of nodes in the circle + -> GraphInfo -- ^ The circular graph with n nodes. +cycleGraph n = + let edges = (n-1, 0) : [(i, i+1) | i <- [0..n-2]] + in GraphInfo n edges + +{- + Generate the line graph of size n +-} +lineGraph :: Int -- ^ n: Number of nodes + -> GraphInfo +lineGraph n = + let edges = [(i, i+1) | i <- [0..n-2]] + in GraphInfo n edges diff --git a/Data/Graph/Generators/Simple.hs b/Data/Graph/Generators/Simple.hs deleted file mode 100644 --- a/Data/Graph/Generators/Simple.hs +++ /dev/null @@ -1,133 +0,0 @@ -{-# LANGUAGE Safe #-} - -{- - Graph generators for simple parametric graphs. - - Built using NetworkX 1.8.1, see --} -module Data.Graph.Generators.Simple ( - completeGraph, - completeGraphWithSelfloops, - completeBipartiteGraph, - emptyGraph, - barbellGraph, - generalizedBarbellGraph, - cycleGraph - ) where - -import Data.Graph.Generators - -{- - Generate a completely connected graph with n nodes. - - The generated graph contains node labels [0..n-1] - - In contrast to 'completeGraphWithSelfloops' this function - does not generate self-loops. - - Contains only one edge between two connected nodes, - use 'Data.Graph.Inductive.Basic.undir' to make it - quasi-undirected. The generated edge (i,j) satisfied @i < j@. --} -completeGraph :: Int -- ^ The number of nodes in the graph - -> GraphInfo -- ^ The resulting complete graph -completeGraph n = - let allNodes = [0..n-1] - allEdges = [(i,j) | i <- allNodes,j <- allNodes, i < j] - in GraphInfo n allEdges - -{- - Variant of 'completeGraph' generating self-loops. - - The generated edge (i,j) satisfied @i <= j@. - - See 'completeGraph' for a more detailed behaviour description --} -completeGraphWithSelfloops :: Int -- ^ The number of nodes in the graph - -> GraphInfo -- ^ The resulting complete graph -completeGraphWithSelfloops n = - let allNodes = [0..n-1] - allEdges = [(i, j) | i <- allNodes, j <- allNodes, i <= j] - in GraphInfo n allEdges - -{- - Generate the complete bipartite graph with n1 nodes in - the first partition and n2 nodes in the second partition. - - Each node in the first partition is connected to each node - in the second partition. - - The first partition nodes are identified by [0..n1-1] - while the nodes in the second partition are identified - by [n1..n1+n2-1] - - Use 'Data.Graph.Inductive.Basic.undir' to also add edges - from the second partition to the first partition. --} -completeBipartiteGraph :: Int -- ^ The number of nodes in the first partition - -> Int -- ^ The number of nodes in the second partition - -> GraphInfo -- ^ The resulting graph -completeBipartiteGraph n1 n2 = - let nodesP1 = [0..n1-1] - nodesP2 = [n1..n1+n2-1] - allEdges = [(i, j) | i <- nodesP1, j <- nodesP2] - in GraphInfo (n1+n2) allEdges - -{- - Generates the empty graph with n nodes and zero edges. - - The nodes are labelled [0..n-1] --} -emptyGraph :: Int -> GraphInfo -emptyGraph n = GraphInfo n [] - -{- - Generate the barbell graph, consisting of two complete subgraphs - connected by a single path. - - In contrast to 'generalizedBarbellGraph', this function always - generates identically-sized bells. Therefore this is a special - case of 'generalizedBarbellGraph' --} -barbellGraph :: Int -- ^ The number of nodes in the complete bells - -> Int -- ^ The number of nodes in the path, - -- i.e the number of nodes outside the bells - -> GraphInfo -- ^ The resulting barbell graph -barbellGraph n np = generalizedBarbellGraph n np n - -{- - Generate the barbell graph, consisting of two complete subgraphs - connected by a single path. - - Self-loops are not generated. - - The nodes in the first bell are identified by [0..n1-1] - The nodes in the path are identified by [n1..n1+np-1] - The nodes in the second bell are identified by [n1+np..n1+np+n2-1] - - The path only contains edges --} -generalizedBarbellGraph :: Int -- ^ The number of nodes in the first bell - -> Int -- ^ The number of nodes in the path, i.e. - -- the number of nodes outside the bells - -> Int -- ^ The number of nodes in the second bell - -> GraphInfo -- ^ The resulting barbell graph -generalizedBarbellGraph n1 np n2 = - let nodesP1 = [0..n1-1] - nodesPath = [n1..n1+np-1] - nodesP2 = [n1+np..n1+np+n2-1] - edgesP1 = [(i, j) | i <- nodesP1, j <- nodesP1, i /= 2] - edgesPath = [(i, i+1) | i <- [n1+np..n1+np+n2]] - edgesP2 = [(i, j) | i <- nodesP2, j <- nodesP2] - in GraphInfo (n1+np+n2) (edgesP1 ++ edgesPath ++ edgesP2) - -{- - Generate the cycle graph of size n. - - Edges are created from lower node IDs to higher node IDs. --} -cycleGraph :: Int -- ^ n: Number of nodes in the circle - -> GraphInfo -- ^ The circular graph with n nodes. -cycleGraph n = - let edges = (n-1, 0) : [(i, i+1) | i <- [0..n-2]] - in GraphInfo n edges diff --git a/GraphGeneratorsTest.hs b/GraphGeneratorsTest.hs --- a/GraphGeneratorsTest.hs +++ b/GraphGeneratorsTest.hs @@ -3,7 +3,7 @@ import Control.Exception (evaluate) import Control.Monad import Data.Graph.Generators.Classic -import Data.Graph.Generators.Simple +import Data.Graph.Generators.Regular import Data.Graph.Generators.Random.ErdosRenyi import Data.Graph.Generators.Random.BarabasiAlbert import Data.Graph.Generators @@ -38,10 +38,15 @@ truncatedCubeGraph `shouldSatisfy` checkGraphInfo truncatedTetrahedronGraph `shouldSatisfy` checkGraphInfo tutteGraph `shouldSatisfy` checkGraphInfo - describe "Simple graphs" $ do + describe "Complete graphs" $ do it "should pass the integrity checks" $ do - forM_ [0..10] $ \n -> + forM_ [0..10] $ \n -> completeGraph n `shouldSatisfy` checkGraphInfo + --it "should have n^2/2 edges" $ do + describe "Regular graphs" $ do + it "should pass the integrity checks" $ do + forM_ [0..25] $ \n -> + lineGraph n `shouldSatisfy` checkGraphInfo describe "Erdös Renyi random graphs" $ do it "should pass the integrity checks" $ do forM_ [0..20] $ \n -> do diff --git a/graph-generators.cabal b/graph-generators.cabal --- a/graph-generators.cabal +++ b/graph-generators.cabal @@ -1,5 +1,5 @@ name: graph-generators -version: 0.1.0.0 +version: 0.1.1.0 synopsis: Functions for generating structured or random FGL graphs description: Generators for graphs. Supports classic (constant-sized) graphs, deterministic Generators @@ -30,7 +30,7 @@ library exposed-modules: Data.Graph.Generators, Data.Graph.Generators.Classic, - Data.Graph.Generators.Simple, + Data.Graph.Generators.Regular, Data.Graph.Generators.FGL, Data.Graph.Generators.Random.ErdosRenyi, Data.Graph.Generators.Random.BarabasiAlbert