Double integration of an array with variables x and y

in this expression, the P matrix is a 8x8 matrix which depends on variables x and y. I need to perform double integration on this function P as P*dx*dy with limits as 0<x<1 and 0<y<1. what command should i use? I cant write P in terms of x and y here.

P=Bmat.'*Dmat*Bmat;

[Torsten]

So P(i,j) is P(x_i,y_j) where 0=x_1<x_2<...<x_8=1 and 0=y_1<y_2<...<y_8=1 ?

[Manish Kumar]

No 0 and 1 are the integration limits of P. P is a function with its elements as functions of x and Y.

[Torsten]

So each element of the matrix P is a function ? Then integrate each of the elements of P separately in a double-for loop.