DoubleMatrixApply Method

Evaluates the specified function at each entry of this instance, and returns a matrix whose entries are given by the corresponding function values.

Definition

Namespace: Novacta.Analytics
Assembly: Novacta.Analytics (in Novacta.Analytics.dll) Version: 2.1.0+428f3840cfab98dda567bb0ed350b302533e273a

C#

public DoubleMatrix Apply(
	Func<double, double> func
)

VB

Public Function Apply ( 
	func As Func(Of Double, Double)
) As DoubleMatrix

C++

public:
DoubleMatrix^ Apply(
	Func<double, double>^ func
)

F#

member Apply : 
        func : Func<float, float> -> DoubleMatrix

Parameters

func FuncDouble, Double: The function to apply to each matrix entry.

Return Value

DoubleMatrix
A matrix whose entries are given by the values the specified function takes on at the entries of this instance.

Remarks

Let LaTeX equation be a matrix, and consider its generic entry

where and are the number of rows and columns of , respectively.

Let LaTeX equation the function represented by func. Then method Apply(FuncDouble, Double) returns a matrix, say , having the same dimensions of by setting

Example

In the following example, a new matrix is built by squaring all the entries in a given matrix.

C#

using System;

namespace Novacta.Analytics.CodeExamples
{
    public class OutPlaceApplyExample0  
    {
        public void Main()
        {
            // Create a matrix.
            var data = new double[20] {
                1, 8, -3,  6, -2,
                2, 2,  2,  0,  7,
               -3, 9,  3,  2,  9,
                5, 2, -5, -1, -4
            };
            var matrix = DoubleMatrix.Dense(4, 5, data, StorageOrder.RowMajor);
            Console.WriteLine("The data matrix:");
            Console.WriteLine(matrix);

            // Return a matrix obtained by adding 1 to each entry
            // of the initial matrix.
            var plusOneMatrix = matrix.Apply((x) => x + 1);

            Console.WriteLine();
            Console.WriteLine("Matrix obtained by adding 1 to each entry:");
            Console.WriteLine(plusOneMatrix);

            // Add one using a read-only wrapper of the data matrix.
            ReadOnlyDoubleMatrix readOnlyMatrix = matrix.AsReadOnly();
            var plusOneReadOnlyMatrix = readOnlyMatrix.Apply((x) => x + 1);

            Console.WriteLine();
            Console.WriteLine("Adding 1 to each entry of a read only matrix:");
            Console.WriteLine(plusOneReadOnlyMatrix);
        }
    }
}

// Executing method Main() produces the following output:
// 
// The data matrix:
// 1                8                -3               6                -2               
// 2                2                2                0                7                
// -3               9                3                2                9                
// 5                2                -5               -1               -4               
// 
// 
// 
// Matrix obtained by adding 1 to each entry:
// 2                9                -2               7                -1               
// 3                3                3                1                8                
// -2               10               4                3                10               
// 6                3                -4               0                -3               
// 
// 
// 
// Adding 1 to each entry of a read only matrix:
// 2                9                -2               7                -1               
// 3                3                3                1                8                
// -2               10               4                3                10               
// 6                3                -4               0                -3               
// 
//

Exceptions

ArgumentNullException

func is null.