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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: