/Hvolume-Matlab

Matlab script for computing the H-volume of a measure

Primary LanguageMATLABMIT LicenseMIT

Hvolume

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Calculates the H-volume (generalised volume) of an n-box in a space with some measure H. Usefull in probability theory, the H-volume computes the probability measure within some n-box from a multivartiate cdf H.

An n-box J is a hyper-rectangle made from the carteesian product of n intervals:

Carteesian product

The two dimensional calculation is:

2D formula

H-volume illustration 2D

The general formula is:

General formula for H-volume

where the sum is taken over every vertex of J.

Code

Vol = Hvolume(measure, J1, J2, .. , Jn)

measure is an anonymous function of dimension n and J1 to Jn are n intervals defining the n-box.

1D

>> C1 = @(x) unifcdf(x,0,1);
>> H1 = Hvolume(C1,[0,0.5])

H1 =

    0.5000
    

2D

>> Rho2 =[1, 0; 0, 1];
>> C2 = @(x) copulacdf('Gaussian', [x(1), x(2)],Rho2);
>> H2 = Hvolume(C2,[0,0.5],[0,0.5])

H2 =

    0.2500

3D

>> Rho3 =eye(3);
>> C3 = @(x) copulacdf('Gaussian', [x(1),x(2),x(3)],Rho3);
>> H3 = Hvolume(C3,[0,0.5], [0,0.5], [0,0.5])

H3 =

    0.1250
    

4D

>> Rho4 =eye(4);
>> C4 = @(x) copulacdf('Gaussian', [x(1),x(2),x(3),x(4)],Rho4);
>> H4 = Hvolume(C4,[0,0.5], [0,0.5], [0,0.5], [0,0.5])

H4 =

    0.0625
    

References

  • Schweizer, B. and Sklar, A., 2011. Probabilistic metric spaces. Courier Corporation.

  • Ferson, S., R. Nelsen, J. Hajagos, D. Berleant, J. Zhang, W.T. Tucker, L. Ginzburg and W.L. Oberkampf. 2004. Dependence in Probabilistic Modeling, Dempster-Shafer Theory, and Probability Bounds Analysis. Sandia National Laboratories, SAND2004-3072, Albuquerque, NM