Section: Inspection Functions
y = isinf(x)
The result is a logical array of the same size as x,
which is true if x is not-a-number, and false otherwise.
Note that for complex or dcomplex data types that
the result is true if either the real or imaginary parts
are infinite.
inf:
--> a = [1.2 3.4 inf 5]
a = 
    1.2000    3.4000 Inf    5.0000 
--> isinf(a)
ans = 
 0 0 1 0 
--> b = 3./[2 5 0 3 1]
b = 
    1.5000    0.6000 Inf    1.0000    3.0000