MATLAB: Mean value of each cell of 2D grid

cell valuesgridmean valuessurfacetemperature map

Hi I am trying to solve a problem that has x,y data and f(x,y). It's a 2D temp map with f(x,y) being temperature values.

I have too many x (3000 values) and y (3000) values and f(x,y) (3000) values.

When I plot surface 2D it generates very odd map with too much of data. To avoid that I am looking to reduce the number of grid points by taking some avg. This way I can reduce the number of grid points.

Can any one has suggestions how to do matlab code for this?

Best Answer

Look at Jan's answer here. He provides MATLAB code and a refernce to the File Exchange. For your convienance:

X = rand(20, 30);
R = reshape(X, 2, 10, 2, 15);
S = sum(sum(R, 1), 3) * 0.25;
Y = reshape(S, 10, 15);

https://www.mathworks.com/matlabcentral/fileexchange/24812-blockmean

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X = rand(20, 30);
R = reshape(X, 2, 10, 2, 15);
S = sum(sum(R, 1), 3) * 0.25;
Y = reshape(S, 10, 15);

This can be wriiten in one line also. If more speed is needed you can use the faster C-Mex FEX: BlockMean.

MATLAB: Dear Reserach Team! I need to calculate numerically definite integral of a function g(y), where g(y) is a numerical integral of f(x,y). Please advise how to do it (the details are shown below). Many thanks in advance!.

function main
  g = @(y) integral(@(x)f(x,y),0,1);
  s = integral(g,0,2,'ArrayValued',true)
end
function fun_f = f(x,y)
  if y==0
    fun_f = x.^2;
  else
    fun_f = x.*sin(x.*y)./y;
  end
end

Best Answer

Related Solutions

MATLAB: How to reduce a matrix size

MATLAB: Dear Reserach Team! I need to calculate numerically definite integral of a function g(y), where g(y) is a numerical integral of f(x,y). Please advise how to do it (the details are shown below). Many thanks in advance!.

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