Get the free memory in GB

/// @brief Return the amount of free memory in GB
///
Function GetFreeMemory()
    variable freeMem
 
#if defined(IGOR64)
    freeMem = NumberByKey("PHYSMEM", IgorInfo(0)) - NumberByKey("USEDPHYSMEM", IgorInfo(0))
#else
    freeMem = NumberByKey("FREEMEM", IgorInfo(0))
#endif
 
    return freeMem / 1024 / 1024 / 1024
End