TOpenCLMatrix.NormL2 Method

Overload List

#	Signature	Description
1	Double NormL2	Calculate the L2-norm of the calling vector.
	└ indexed: Double NormL2(Int32 Index, Int32 Len)
2	Double NormL2(TOpenCLMtxVec Vec, Boolean RelativeError)	The L2-norm.
	└ indexed: Double NormL2(TOpenCLMtxVec Vec, Int32 VecIndex, Int32 Index, Int32 Len, Boolean RelativeError)

Overload 1: Double NormL2

Calculate the L2-norm of the calling vector.

Returns: Double - L2 norm, defined by: NormaL2 = ( Sum(|a[i]|^2) )^0.5 , 0 < i < Length-1 .

Indexed: Double NormL2(Int32 Index, Int32 Len)

Calculates the L2 norm from calling vector elements [Index]..[Index+Len-1].

#	Name	Type	Description
1	Index	Int32	start index
2	Len	Int32	element count

Returns: Double

Overload 2: Double NormL2(TOpenCLMtxVec Vec, Boolean RelativeError)

The L2-norm.

#	Name	Type	Description
1	Vec	TOpenCLMtxVec	source TOpenCLVector or TOpenCLMatrix
2	RelativeError	Boolean

Returns: Double - L2 norm, defined by ||V-Vec||, where V is calling vector.

Remarks:

If the NormL2 is called without any parameters, the NormL2 calculates the norm of calling vector. The L2 norm of ||V-Vec|| is defined by the formula:

\|\text{V} - \text{Vec}\| _{L2} = \sqrt{\sum _{k=0} ^{\text{Length}-1}\left(|\text{V}[k]-\text{Vec}[k]| \right)^2}

If RelativeError is true then the computed norm is divided by the norm of V, and the function returns the "relative error":

\frac{\| \text{V} - \text{Vec}\|}{\|\text{V}\|}

Examples

using Dew.Math;
using Dew.Math.Units;

namespace Dew.Examples
{
    void Example()
    {
        clMtxVec.TOpenCLMatrix a,b;
        clMtxVec.CreateIt(out a, out b);
        try
        {
            a.Size(2,2, TclFloatPrecision.clFloat, false);
            b.Size(2,2, TclFloatPrecision.clFloat, false);

            a.CopyFromArray(new double[] {1,2,3,4});
            b.CopyFromArray(new double[] {4,3,2,1});

            double c = a.NormL2(b,true);
        }
        finally
        {
            clMtxVec.FreeIt(ref a,ref b);
        }
    }
}

Indexed: Double NormL2(TOpenCLMtxVec Vec, Int32 VecIndex, Int32 Index, Int32 Len, Boolean RelativeError)

Calculates the L2 norm ||V-Vec|| between Vec elements [VecIndex]..[VecIndex+Len-1] and calling vector elements [Index]..[Index+Len-1].

#	Name	Type	Description
1	Vec	TOpenCLMtxVec	source TOpenCLVector or TOpenCLMatrix
2	VecIndex	Int32
3	Index	Int32	start index
4	Len	Int32	element count
5	RelativeError	Boolean

Returns: Double