Getting Started

Scalar Expansion

Matrices and scalars can be combined in several different ways. For example, a scalar is subtracted from a matrix by subtracting it from each element. The average value of the elements in our magic square is 8.5, so

B = A - 8.5

forms a matrix whose column sums are zero.

B =
      7.5     -5.5     -6.5      4.5
     -3.5      1.5      2.5     -0.5
      0.5     -2.5     -1.5      3.5
     -4.5      6.5      5.5     -7.5

sum(B)

ans =
     0     0     0     0

With scalar expansion, MATLAB assigns a specified scalar to all indices in a range. For example,

B(1:2,2:3) = 0

zeros out a portion of B

B =
      7.5        0        0      4.5
     -3.5        0        0     -0.5
      0.5     -2.5     -1.5      3.5
     -4.5      6.5      5.5     -7.5

Multivariate Data

Logical Subscripting