#12: Adds -cycles and -matrix flags.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## v0.2.0
 
+* #12: Add cycle and matrix output to lsap command
+  * `lsap` provides `-cycles` and `-matrix` flags for assignment forms.
+  * `ap.Matrix` is now a `[][]int8` instead of `[][]bool`.
 * #10: Add reduced cost and dual price output to lsap command
   * `lsap` uses `-dual` and `-rc` flags for dual prices and reduced costs.
 * #6: Provide Cycle struct and method

README.md

@@ -126,8 +126,12 @@ Usage:
         ]
         EOF
 Flags:
+        -cycles
+                output cyclic assignment form
         -dual
                 output dual prices
+        -matrix
+                output matrix assignment form
         -rc
                 output reduced cost matrix
 ```

cmd/lsap/lsap.go

@@ -27,7 +27,9 @@ func usage() {
 }
 
 func main() {
+	cycles := flag.Bool("cycles", false, "output cyclic assignment form")
 	dual := flag.Bool("dual", false, "output dual prices")
+	matrix := flag.Bool("matrix", false, "output matrix assignment form")
 	rc := flag.Bool("rc", false, "output reduced cost matrix")
 	flag.Usage = usage
 	flag.Parse()
@@ -44,10 +46,18 @@ func main() {
 		"cost":        a.Cost(),
 	}
 
+	if *cycles {
+		out["cycles"] = p.Cycles()
+	}
+
 	if *dual {
 		out["dual"] = a.DualPrices()
 	}
 
+	if *matrix {
+		out["matrix"] = p.Matrix()
+	}
+
 	if *rc {
 		rcMatrix := make([][]int64, len(p))
 		for u := range p {

cycles.go

@@ -45,7 +45,7 @@ func (c Cycles) Inverse() Cycles {
 func (c Cycles) Matrix() Matrix {
 	m := make(Matrix, c.len())
 	for u := range m {
-		m[u] = make([]bool, len(m))
+		m[u] = make([]int8, len(m))
 	}
 
 	for _, cycle := range c {
@@ -54,7 +54,7 @@ func (c Cycles) Matrix() Matrix {
 			if i < len(cycle)-1 {
 				v = cycle[i+1]
 			}
-			m[u][v] = true
+			m[u][v] = 1
 		}
 	}
 

cycles_test.go

@@ -16,12 +16,6 @@ func ExampleCycles() {
 	// Output:
 	// [[0 1] [2] [3 6 4 5]]
 	// [[0 1] [2] [3 5 4 6]]
-	// - X - - - - -
-	// X - - - - - -
-	// - - X - - - -
-	// - - - - - - X
-	// - - - - - X -
-	// - - - X - - -
-	// - - - - X - -
+	// [[0 1 0 0 0 0 0] [1 0 0 0 0 0 0] [0 0 1 0 0 0 0] [0 0 0 0 0 0 1] [0 0 0 0 0 1 0] [0 0 0 1 0 0 0] [0 0 0 0 1 0 0]]
 	// [1 0 2 6 5 3 4]
 }

matrix.go

@@ -1,10 +1,8 @@
 package ap
 
-import "strings"
-
 // Matrix representation of an assignment. If u is assigned to v, then M[u][v]
 // is true. Each row and each column has exactly one true element.
-type Matrix [][]bool
+type Matrix [][]int8
 
 // Cycles converts a permutation matrix to a cyclic representation.
 func (m Matrix) Cycles() Cycles {
@@ -21,30 +19,11 @@ func (m Matrix) Permutation() Permutation {
 	p := make(Permutation, len(m))
 	for u, mu := range m {
 		for v, assigned := range mu {
-			if assigned {
+			if assigned == 1 {
 				p[u] = v
 				break
 			}
 		}
 	}
 	return p
 }
-
-func (m Matrix) String() string {
-	s := make([]string, len(m))
-	for u, mu := range m {
-		s[u] = rowString(mu)
-	}
-	return strings.Join(s, "\n")
-}
-
-func rowString(row []bool) string {
-	s := make([]string, len(row))
-	for i, v := range row {
-		s[i] = "-"
-		if v {
-			s[i] = "X"
-		}
-	}
-	return strings.Join(s, " ")
-}

matrix_test.go

@@ -8,34 +8,22 @@ import (
 
 func ExampleMatrix() {
 	m := ap.Matrix{
-		{false, true, false, false, false, false, false},
-		{true, false, false, false, false, false, false},
-		{false, false, true, false, false, false, false},
-		{false, false, false, false, false, false, true},
-		{false, false, false, false, false, true, false},
-		{false, false, false, true, false, false, false},
-		{false, false, false, false, true, false, false},
+		{0, 1, 0, 0, 0, 0, 0},
+		{1, 0, 0, 0, 0, 0, 0},
+		{0, 0, 1, 0, 0, 0, 0},
+		{0, 0, 0, 0, 0, 0, 1},
+		{0, 0, 0, 0, 0, 1, 0},
+		{0, 0, 0, 1, 0, 0, 0},
+		{0, 0, 0, 0, 1, 0, 0},
 	}
 	fmt.Println(m)
 	fmt.Println(m.Cycles())
 	fmt.Println(m.Inverse())
 	fmt.Println(m.Permutation())
 
 	// Output:
-	// - X - - - - -
-	// X - - - - - -
-	// - - X - - - -
-	// - - - - - - X
-	// - - - - - X -
-	// - - - X - - -
-	// - - - - X - -
+	// [[0 1 0 0 0 0 0] [1 0 0 0 0 0 0] [0 0 1 0 0 0 0] [0 0 0 0 0 0 1] [0 0 0 0 0 1 0] [0 0 0 1 0 0 0] [0 0 0 0 1 0 0]]
 	// [[0 1] [2] [3 6 4 5]]
-	// - X - - - - -
-	// X - - - - - -
-	// - - X - - - -
-	// - - - - - X -
-	// - - - - - - X
-	// - - - - X - -
-	// - - - X - - -
+	// [[0 1 0 0 0 0 0] [1 0 0 0 0 0 0] [0 0 1 0 0 0 0] [0 0 0 0 0 1 0] [0 0 0 0 0 0 1] [0 0 0 0 1 0 0] [0 0 0 1 0 0 0]]
 	// [1 0 2 6 5 3 4]
 }

permutation.go

@@ -49,8 +49,8 @@ func (p Permutation) Inverse() Permutation {
 func (p Permutation) Matrix() Matrix {
 	m := make(Matrix, len(p))
 	for u, v := range p {
-		m[u] = make([]bool, len(p))
-		m[u][v] = true
+		m[u] = make([]int8, len(p))
+		m[u][v] = 1
 	}
 	return m
 }

permutation_test.go

@@ -17,11 +17,5 @@ func ExamplePermutation() {
 	// [1 0 2 6 5 3 4]
 	// [[0 1] [2] [3 6 4 5]]
 	// [1 0 2 5 6 4 3]
-	// - X - - - - -
-	// X - - - - - -
-	// - - X - - - -
-	// - - - - - - X
-	// - - - - - X -
-	// - - - X - - -
-	// - - - - X - -
+	// [[0 1 0 0 0 0 0] [1 0 0 0 0 0 0] [0 0 1 0 0 0 0] [0 0 0 0 0 0 1] [0 0 0 0 0 1 0] [0 0 0 1 0 0 0] [0 0 0 0 1 0 0]]
 }