Matlab array 64 Bit#

Let's first assume you have a function that you want to apply to each element of A (called my_func). There are also a couple of functions you can use: arrayfun and cellfun.

Matlab array 64 Bit#

(Though I don't use a 64 bit MATLAB release, I believe that problem has been resolved for those lucky individuals who do.)ДЄs pointed out in a few other answers, you can iterate over all elements in a matrix A (of any dimension) using a linear index from 1 to numel(A) in a single for loop. It is really only an issue if you use sparse matrices often, when occasionally this will cause a problem. So if your array has more then a total of 2^32 elements in it, the linear index will fail. MATLAB uses a 32 bit integer to store these indexes. The only problem with the linear index is when they get too large. So you can use it on structures, cell arrays, etc. The linear index applies in general to any array in matlab. Conversion between the linear index and two (or higher) dimensional subscripts is accomplished with the sub2ind and ind2sub functions. There are many circumstances where the linear index is more useful.

For example, if we wanted to square the elements of A (yes, I know there are better ways to do this), one might do this: B = zeros(size(A)) The result is, we can access each element in turn of a general n-d array using a single loop. In fact, the function find returns its results as a linear index. A(:)ДЄs you can see, the 8th element is the number 7. We can see the order the elements are stored in memory by unrolling the array into a vector. MATLAB allows you to use either a row and column index, or a single linear index. An array in MATLAB is really just a vector of elements, strung out in memory.

The idea of a linear index for arrays in matlab is an important one.