create a matrix with elements as mean values of another matrix

Hello,

Please help me with the following.

Consider a 100x10 matrix, called A.

How can I get a 100x10 matrix, called B, where each row is the mean of preseding rows of A?

For matrix B,

row1 = row1 of A

row2 = mean (row1,row2) of A

...

row100= mean(row1,row2,...,row100) of A

Thank you very much.

Best,

Pavlos

Answer 1

[Azzi Abdelmalek]

A=[1 2 3;4 5 6;7 8 9]  % Example
[n,m]=size(A);
B=cumsum(A)./repmat((1:n)',1,m)

%or

A=[1 2 3;4 5 6;7 8 9]
B=bsxfun(@rdivide,cumsum(A),(1:size(A,1))')

[Jos (10584)]

+1

Answer 2

[Jos (10584)]

Just to show the many roads to Rome in MatLab's world:

A = ceil(10*rand(10,4))
B = cell2mat(arrayfun(@(x) sum(A(1:x,:),1)/x, 1:size(A,1), 'un', 0).')