Package: coder
Declare uninitialized variables
X = coder.nullcopy(A)
X = coder.nullcopy(A)A to X,
but does not copy element values. Preallocates memory for X without
incurring the overhead of initializing memory.
Use this function with caution. See How to Eliminate Redundant Copies by Defining Uninitialized Variables.
The following example shows how to declare variable X as
a 1-by-5 vector of real doubles without performing an unnecessary
initialization:
function X = foo
N = 5;
X = coder.nullcopy(zeros(1,N));
for i = 1:N
if mod(i,2) == 0
X(i) = i;
else
X(i) = 0;
end
endUsing coder.nullcopy with zeros lets you specify the size of vector X without
initializing each element to zero.
coder.nullcopy does not support MATLAB® classes as inputs.
You cannot use coder.nullcopy on sparse matrices, or on
structures, cell arrays, or classes that contain sparse matrices.