github.com/gopherd/gonum@v0.0.4/graph/complement_test.go (about)

     1  // Copyright ©2019 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package graph_test
     6  
     7  import (
     8  	"fmt"
     9  	"testing"
    10  
    11  	"math/rand"
    12  
    13  	"github.com/gopherd/gonum/graph"
    14  	"github.com/gopherd/gonum/graph/graphs/gen"
    15  	"github.com/gopherd/gonum/graph/iterator"
    16  	"github.com/gopherd/gonum/graph/simple"
    17  )
    18  
    19  var complementTests = []struct {
    20  	g graph.Graph
    21  }{
    22  	{g: gnp(100, 0, rand.NewSource(1))},
    23  	{g: gnp(100, 0.05, rand.NewSource(1))},
    24  	{g: gnp(100, 0.5, rand.NewSource(1))},
    25  	{g: gnp(100, 0.95, rand.NewSource(1))},
    26  	{g: gnp(100, 1, rand.NewSource(1))},
    27  }
    28  
    29  func TestComplement(t *testing.T) {
    30  	for _, test := range complementTests {
    31  		n := len(graph.NodesOf(test.g.Nodes()))
    32  		wantM := n * (n - 1) // Double counting edges, but no self-loops.
    33  
    34  		var gotM int
    35  		iter := test.g.Nodes()
    36  		for iter.Next() {
    37  			id := iter.Node().ID()
    38  			to := test.g.From(id)
    39  			for to.Next() {
    40  				gotM++
    41  			}
    42  			toC := graph.Complement{test.g}.From(id)
    43  			for toC.Next() {
    44  				gotM++
    45  			}
    46  		}
    47  		if gotM != wantM {
    48  			t.Errorf("unexpected number of edges in sum of input and complement: got:%d want:%d", gotM, wantM)
    49  		}
    50  	}
    51  }
    52  
    53  func gnp(n int, p float64, src rand.Source) *simple.UndirectedGraph {
    54  	g := simple.NewUndirectedGraph()
    55  	err := gen.Gnp(g, n, p, src)
    56  	if err != nil {
    57  		panic(fmt.Sprintf("gnp: bad test: %v", err))
    58  	}
    59  	return g
    60  }
    61  
    62  var nodeFilterIteratorTests = []struct {
    63  	src, filter graph.Nodes
    64  	root        int64
    65  	len         int
    66  }{
    67  	{src: iterator.NewOrderedNodes([]graph.Node{simple.Node(0)}), filter: graph.Empty, root: 0, len: 0},
    68  	{src: iterator.NewOrderedNodes([]graph.Node{simple.Node(0), simple.Node(1)}), filter: graph.Empty, root: 0, len: 1},
    69  	{src: iterator.NewOrderedNodes([]graph.Node{simple.Node(0), simple.Node(1), simple.Node(2)}), filter: iterator.NewOrderedNodes([]graph.Node{simple.Node(1)}), root: 0, len: 1},
    70  }
    71  
    72  func TestNodeFilterIterator(t *testing.T) {
    73  	for _, test := range nodeFilterIteratorTests {
    74  		it := graph.NewNodeFilterIterator(test.src, test.filter, test.root)
    75  		if it.Len() < 0 {
    76  			t.Logf("don't test indeterminate iterators: %T", it)
    77  			continue
    78  		}
    79  		for i := 0; i < 2; i++ {
    80  			n := it.Len()
    81  			if n != test.len {
    82  				t.Errorf("unexpected length of iterator construction/reset: got:%d want:%d", n, test.len)
    83  			}
    84  			for it.Next() {
    85  				n--
    86  			}
    87  			if n != 0 {
    88  				t.Errorf("unexpected remaining nodes after iterator completion: got:%d want:0", n)
    89  			}
    90  			it.Reset()
    91  		}
    92  	}
    93  }