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 x)
      {
        // 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
    the isfinite manpage, the isinf manpage

