> ## Name

> isnan - test whether or not a scalar or each vector component is not-a-number

> ## Synopsis

>     bool  isnan(float x);
>     bool1 isnan(float1 x);
>     bool2 isnan(float2 x);
>     bool3 isnan(float3 x);
>     bool4 isnan(float4 x);

>     bool   isnan(half x);
>     bool1  isnan(half1 x);
>     bool2  isnan(half2 x);
>     bool3  isnan(half3 x);
>     bool4  isnan(half4 x);

>     bool  isnan(fixed x);
>     bool1 isnan(fixed1 x);
>     bool2 isnan(fixed2 x);
>     bool3 isnan(fixed3 x);
>     bool4 isnan(fixed4 x);

> ## Parameters

> x
>   Vector or scalar to test for being NaN.

> ## Description

> Returns whether or not a scalar or each vector component is not-a-number (NaN) Finite and infinite values are not NaN.

> ## Reference Implementation

> isnan for float3 vectors could be implemented like this.

>     bool3 isnan(float3 s)
>     {
>       // By IEEE 754 rule, NaN is not equal to NaN
>       return s != s;
>     }

> ## Profile Support

> isnan is supported in all profiles except fp20.

> ## See Also

> isfinite, isinf