There is no general solution to this as it could be defined in different ways depending on the number of rows in the matrix: what is 20% of a one row matrix? 20% of a two row matrix? 20% of a four row matrix?
Obviously if the number of rows of the matrix is a multiple of the blocks that you want, then the solution is easy using mat2cell and some simple division to calculate how many rows per block:
>> A = rand(10,4);
>> N = 5;
>> X = size(A);
>> B = mat2cell(A, X(1)/N * ones(1,N), X(2))
B =
[2x4 double]
[2x4 double]
[2x4 double]
[2x4 double]
[2x4 double]
If you can specify how to work with numbers of rows that are not multiples of the number of blocks, then we can show you how to code this too!
