Yo! It works. Thank you.

evalf(Int(Q, 0..1)) really works! Thanks. Now I need to solve differential equation: diff(diff(x(t),t),t)=T(x(t),diff(x(t),t)).

> restart; > with(CurveFitting): > with(LinearAlgebra):with(plots): > Ranges := [[seq(1..5)],[seq(1..5)]]: > Img := [[1,3,2,0,0],[1,2,1,3,3],[3,4,2,1,2],[0,1,2,2,0],[2,3,6,1,0]]: > T:=(x,y)->ArrayInterpolation(Ranges,Img,[[x],[y]],method=spline)[1][1]: > plot3d(T,1..5,1..5,shading=z,grid=[25,25]); > Q:=x->T(x,2.4): > plot(Q,1..5); > T(2.3,4); 2.59687499999517968 > Q(3); 3.40228571428511728 So it can plot T and Q or eval them in points, but I can not use Q in a numerically solved differential equation or numerically integrate it.

I also used instead of curry Q:=x->T(x,3.3): but in any case it does not work. It can not access T as a normal function, only calculation in a point is avalible.