     return Vector(newData, name: v.name, showName: v.showName)
 }
 
+/// Returns the inverse cosine (cos⁻¹) in radians for each element in a matrix data structure.
+///
+/// - Parameter m: A matrix data structure with elements to convert.
+/// - Returns: A matrix data structure with inverse cosine values.
+///
+/// - Warning: A domain error occurs for arguments not in the range [-1, +1].
 public func acos(_ m: Matrix<Double>) -> Matrix<Double>
 {
     let newData = m.data.map({acos($0)})

@_exported import func Darwin.acos
#endif

public func acos(_ v: Vector<Double>) -> Vector<Double>
{
    let newData = v.data.map({acos($0)})

    return Matrix(m.size, newData, name: m.name, showName: m.showName)
}

/// Returns the inverse cosine (cos⁻¹) in radians for each element in a tensor data structure.
///
/// - Parameter t: A tensor data structure with elements to convert.
/// - Returns: A tensor data structure with inverse cosine values.
///
/// - Warning: A domain error occurs for arguments not in the range [-1, +1].
public func acos(_ t: Tensor<Double>) -> Tensor<Double>
{
    let newData = t.data.map({acos($0)})

    return Tensor(t.size, newData, name: t.name, showName: t.showName)
}
