2D interpolation

*To*: mathgroup at smc.vnet.net*Subject*: [mg72901] 2D interpolation*From*: "Jouvenot, Fabrice" <F.Jouvenot at liverpool.ac.uk>*Date*: Wed, 24 Jan 2007 17:33:35 -0500 (EST)

Hello, I am asking (again) for your knowledge to help me. I try to have a 2 dimensional interpolation of points {x, y, f(x,y)}. After some try, I wrote these lines (as an exemple of what I want to do) that works : ________________________________________ data = {{1, 1, -10}, {1, 2, 2}, {1, 3, 3}, {1, 4, 4}, {1, 5, 5}, {2, 1, 2}, {2, 2, 4}, {2, 3, 6}, {2, 4, 8}, {2, 5, 10}, {3., 1, -9}, {3, 2, 6}, {3, 3, 90}, {3, 4, 12}, {3, 5, 15}, {4, 1, 4}, {4, 2, 8}, {4, 3, 12}, {4, 4, 16}, {4, 5, 20}, {5, 1, 5}, {5, 2, 10}, {5, 3, 15}, {5, 4, 20}, {5, 5, 40.5}}; MatrixForm[data] test[x_, y_] := Interpolation[data][x, y]; test[1.5, 1.5] Plot[test[x, 1], {x, 1, 5}]; Plot[test[x, x], {x, 1, 5}]; Plot3D[test[x, y], {x, 1, 5}, {y, 1, 5}]; ________________________________________ The problem is that when I want to use a point with a real x or y like {1.23, 1.1, -10}, nothing works anymore. I think that I miss something essential and fundamental, but I don'y know why... Thanks for your help, Cheers, Fabrice.