Tech-Note 1109: How Do I Vectorize My Code?
The elements of A that are selected have a '1' in the corresponding position of
the subscripting matrix. For example, if A = 1:5, then A(logical([0 0 1 0 1]))
denotes the third and fifth elements of A:
» A = 1:5;
» A(logical([0 0 1 0 1]))
This second type of subscripting is very powerful, and we use it frequently in
the following sections. For more information on subscripting, see the
2. Basic Array Operations: y(i) = fcn(x1(i), x2(i), .
The simplest type of vector operations in MATLAB can be thought of as
. In this approach, the same operation is performed for each
corresponding element in a data set (which may include more than one
Suppose you have some data from an experiment. The data measurements
are the length L, width W, height H, and mass M of an object, and you want to
find the density D of the object. If you had run the experiment once, you would
just have one value for each of the four observables (i.e., L, W, H, and M are
scalars). Here is the calculation you want to run:
D = M/(L*W*H)
Now, suppose that you actually run the experiment 20 times. Now L, W, H, and
M are vectors of length 20, and you want to calculate the corresponding vector
D, which represents the density for each run.
In most programming languages, you would set up a loop, the equivalent of the