Code Analyzer has detected a cell array that is constructed, in part, by extracting all the elements from another cell array. This operation can be inefficient, especially if the existing cell array is large. Typically, it is better to concatenate the new elements with the existing cell array.

Replace {A{:} X} with [A(:)' {X}]. Instead of extracting the cell array (A{:}), reshape the cell array into a row vector (A(:)') and then concatenate the two cell arrays.

If A has a single row, you can simplify the replacement even further to [A {X}].

You also might be able to simplify {X}, depending on what kind of expression it is. For example, if {X} is an expression similar to B{J}, then you might be able to replace it with B(J) or B(J)', depending on the shape of B and J.

For more information, see Combine Cell Arrays.