tests.

matrix/matrix.go

@@ -14,16 +14,26 @@ const (
 
 var (
 	// ErrDimensionMismatch is a typical error.
-	ErrDimensionMismatch = errors.New("matrix is not square, cannot invert")
+	ErrDimensionMismatch = errors.New("dimension mismatch")
 )
 
 // New returns a new matrix.
-func New(rows, cols int) *Matrix {
+func New(rows, cols int, values ...float64) *Matrix {
+	if len(values) == 0 {
+		return &Matrix{
+			rows:     rows,
+			cols:     cols,
+			epsilon:  DefaultEpsilon,
+			elements: make([]float64, rows*cols),
+		}
+	}
+	elems := make([]float64, rows*cols)
+	copy(elems, values)
 	return &Matrix{
 		rows:     rows,
 		cols:     cols,
 		epsilon:  DefaultEpsilon,
-		elements: make([]float64, rows*cols),
+		elements: elems,
 	}
 }
 
@@ -92,9 +102,11 @@ func (m *Matrix) WithEpsilon(epsilon float64) *Matrix {
 
 // Arrays returns the matrix as a two dimensional jagged array.
 func (m *Matrix) Arrays() [][]float64 {
-	a := make([][]float64, m.rows, m.cols)
+	a := make([][]float64, m.rows)
 
 	for row := 0; row < m.rows; row++ {
+		a[row] = make([]float64, m.cols)
+
 		for col := 0; col < m.cols; col++ {
 			a[row][col] = m.Get(row, col)
 		}
@@ -145,7 +157,7 @@ func (m *Matrix) Set(row, col int, val float64) {
 func (m *Matrix) Col(col int) Vector {
 	values := make([]float64, m.rows)
 	for row := 0; row < m.rows; row++ {
-		values[col] = m.Get(row, col)
+		values[row] = m.Get(row, col)
 	}
 	return Vector(values)
 }
@@ -181,6 +193,17 @@ func (m *Matrix) DiagonalVector() Vector {
 	return Vector(values)
 }
 
+// Diagonal returns a matrix from the diagonal of a matrix.
+func (m *Matrix) Diagonal() *Matrix {
+	rank := minInt(m.rows, m.cols)
+	m2 := New(rank, rank)
+
+	for index := 0; index < rank; index++ {
+		m2.Set(index, index, m.Get(index, index))
+	}
+	return m2
+}
+
 // Equals returns if a matrix equals another matrix.
 func (m *Matrix) Equals(other *Matrix) bool {
 	if other == nil && m != nil {
@@ -226,17 +249,6 @@ func (m *Matrix) U() *Matrix {
 	return m2
 }
 
-// Diagonal returns a matrix from the diagonal of a matrix.
-func (m *Matrix) Diagonal() *Matrix {
-	rank := minInt(m.rows, m.cols)
-	m2 := New(rank, rank)
-
-	for index := 0; index < rank; index++ {
-		m2.Set(index, index, m.Get(index, index))
-	}
-	return m2
-}
-
 // String returns a string representation of the matrix.
 func (m *Matrix) String() string {
 	buffer := bytes.NewBuffer(nil)