MATLAB Programming Fundamentals - MathWorks

Memory Requirements for Structure Array

Structure arrays do not require completely contiguous memory. However, each field

requires contiguous memory, as does the header that MATLAB creates to describe the

array. For very large arrays, incrementally increasing the number of fields or the number

of elements in a field results in Out of Memory errors.

Preallocate memory for the contents by assigning initial values with the struct function,

such as

newStruct(1:25,1:50) = struct('a',ones(20),'b',zeros(30),'c',rand(40));

This code creates and populates a 25-by-50 structure array S with fields a, b, and c.

If you prefer not to assign initial values, you can initialize a structure array by assigning

empty arrays to each field of the last element in the structure array, such as

newStruct(25,50).a = [];

newStruct(25,50).b = [];

newStruct(25,50).c = [];

or, equivalently,

newStruct(25,50) = struct('a',[],'b',[],'c',[]);

However, in this case, MATLAB only allocates memory for the header, and not for the

contents of the array.

For more information, see:

• “Reshaping and Rearranging Arrays”


• “How MATLAB Allocates Memory” on page 29-12

11 Structures