isdouble(), issingle(), ..., functions missing in Matlab2015a

Question

When I try:

>>isdouble(1)

I just get the error

Undefined function or variable 'isdouble'.

It is the same for the other is* functions. But these are standard functions in Matlab and I even find them when I use the help or doc functions:

>>help isdouble
isdouble - Determine whether input is double-precision data type

This MATLAB function returns 1 when the DataType property of fi object a is
double, and 0 otherwise.
...

So does anyone know whats going on here?

Answer 1

These functions are a part of the Fixed-Point Designer toolbox, which you might not have. You should use the isa function instead:

isa(1, 'double');