What's the point of 'isinf' function ?

In MATLAB we can use '==' operator to check whether the given variable is a finite or infinite. I'm wondering is there any advantages of using 'isinf' function ? like improvement in execution time or handling of some execptions. Any information is helpful. Thank you.

Answer 1

[Infinite_king]

Reason 1:-

As @Paul and @Walter Roberson pointed out, 'isinf' will make it easier to check for inf values when complex numbers are involved.

Note :- I will add more reasons if I come across any in the future.

Answer 2

[Matt J]

For one thing, it covers cases were the inf elements have mixed signs, thus avoiding the overhead of additional operations like abs().

isinf([-inf, 2, inf, 5])

ans = 1×4 logical array
   1   0   1   0

[Infinite_king]

True. Any other benefits that you can think of ?

[Paul]

isinf can be useful for complex inputs if desired that either real or imaginary part being inf should return true.

x = inf + 1i

x = Inf + 1.0000i

inf == x

ans = logical
   0

isinf(x)

ans = logical
   1

[Walter Roberson]

x = 1 + 1i*inf

x = 1.0000 + Infi

isinf(x)

ans = logical
   1

Huh, looks like it tests the imaginary component as well !

[Paul]

As documented: isinf

"If A contains complex numbers, isinf(A) contains 1 for elements with infinite real or imaginary part, and 0 for elements where both real and imaginary parts are finite or NaN."

[Infinite_king]

Thanks for the comments @Paul and @Walter Roberson. I guess that is a good enough reason to use 'isinf' instead of '==' operator.