# NMath User's Guide

5.7 Generic Functions (.NET, C#, CSharp, VB, Visual Basic, F#)

NMath provides convenience methods for applying unary and binary functions to elements of a vector. Each of these methods takes a function delegate. The Apply() method returns a new vector whose contents are the result of applying the given function to each element of the vector. The Transform() method modifies a vector object by applying the given function to each of its elements. For example, assuming MyFunc is a function that takes a double and returns a double:

Code Example – C# vector

```var v = new DoubleVector ( 10, 0, -1 );

// Construct a delegate for MyFunc
Func<double, double> MyFuncDelegate =
new Func<double, double>( MyFunc );

// Construct a new vector whose values are the result of applying
// MyFunc to the values in vector v. v remains unchanged.
DoubleVector w = v.Apply( MyFuncDelegate );

// Transform the contents of v.
v.Transform( MyFuncDelegate );

v == w; // true!
```

Code Example – VB vector

```Dim V As New DoubleVector(10, 0, -1)

' Construct a delegate for MyFunc
Dim MyFuncDelegate As New Func(Of Double, Double)(AddressOf MyFunc)

' Construct a new vector whose values are the result of applying
' MyFunc to the values in vector v. v remains unchanged.
Dim W As DoubleVector = V.Apply(MyFuncDelegate)

' Transform the contents of v.
V.Transform(MyFuncDelegate)

V = W ' true!
```

NMath provides delegates for many commonly used math functions in the NMathFunctions class.

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