isnan
isnan |
Purpose
Test whether a real value is valid.
Synopsis
function isnan(r: real):boolean
Argument
|
r
|
The value to test
|
Return value
true if the value is not valid (
i.e. it corresponds to
Not A Number).
Further information
When the parameter
matherr is set to
true (see
setparam) mathematical functions return the constant
NAN
or
INFINITY instead of failing. This function can be used to identify incorrect results (direct comparison to
NAN or
INFINITY always fails).
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