diff --git a/cmd/internal/graph/common.go b/cmd/internal/graph/common.go
index 9d242a1..2783b83 100644
--- a/cmd/internal/graph/common.go
+++ b/cmd/internal/graph/common.go
@@ -23,6 +23,7 @@ import (
 
 type WeightedGraph interface {
 	graph.Weighted
+	graph.WeightedMultigraph
 	graph.WeightedMultigraphBuilder
 
 	WeightedEdges() graph.WeightedEdges
diff --git a/cmd/internal/graph/dot/graph.go b/cmd/internal/graph/dot/graph.go
index 8291e76..0a55aaa 100644
--- a/cmd/internal/graph/dot/graph.go
+++ b/cmd/internal/graph/dot/graph.go
@@ -41,7 +41,7 @@ func NewDOTUndirectedGraph(weightAttr string) DOTWeightedGraph {
 }
 
 // NewLine returns a DOT-aware weighted line.
-func (g *DOTWeightedGraph) NewLine(from, to graph.Node) graph.Line {
+func (g DOTWeightedGraph) NewLine(from, to graph.Node) graph.Line {
 	var defaultWeight float64
 	if g.WeightAttribute == "" {
 		defaultWeight = 1
@@ -54,11 +54,11 @@ func (g *DOTWeightedGraph) NewLine(from, to graph.Node) graph.Line {
 }
 
 // NewNode returns a DOT-aware Node.
-func (g *DOTWeightedGraph) NewNode() graph.Node {
+func (g DOTWeightedGraph) NewNode() graph.Node {
 	return &Node{Node: g.WeightedGraph.NewNode()}
 }
 
 // SetLine adds a DOT-aware weighted line to the graph.
-func (g *DOTWeightedGraph) SetLine(e graph.Line) {
+func (g DOTWeightedGraph) SetLine(e graph.Line) {
 	g.WeightedGraph.SetWeightedLine(e.(*weightedLine))
 }
diff --git a/cmd/root.go b/cmd/root.go
index 770dd51..b641dbe 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -25,6 +25,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"gonum.org/v1/gonum/graph/encoding/dot"
+	dotfmt "gonum.org/v1/gonum/graph/formats/dot"
 	"gonum.org/v1/gonum/mat"
 )
 
@@ -60,7 +61,19 @@ func parse(cmd *cobra.Command, args []string) {
 		panic(err)
 	}
 
-	graph := idot.NewDOTDirectedGraph(weightAttr)
+	ast, err := dotfmt.ParseBytes(data)
+	if err != nil {
+		panic(err)
+	}
+
+	first := ast.Graphs[0]
+	var graph idot.DOTWeightedGraph
+	if first.Directed {
+		graph = idot.NewDOTDirectedGraph(weightAttr)
+	} else {
+		graph = idot.NewDOTUndirectedGraph(weightAttr)
+	}
+
 	err = dot.UnmarshalMulti(data, graph)
 	if err != nil {
 		panic(err)
@@ -74,7 +87,7 @@ func parse(cmd *cobra.Command, args []string) {
 	outputMatrix(matrix)
 }
 
-func orderedAdjMatrix(g *idot.DOTDirectedGraph) (*mat.Dense, error) {
+func orderedAdjMatrix(g idot.DOTWeightedGraph) (*mat.Dense, error) {
 	matrix := g.AdjacencyMatrix()
 	if len(nodeOrder) == 0 {
 		return matrix, nil