if($Config{nvsize} == 8)   { $nvbits =  64 }
elsif(length(sqrt 2) > 25) { $nvbits = 128 }
else                       { $nvbits =  80 }
$defines .= ' -DLU_NV_BITS='.$nvbits;

##</code><code>##

#if LU_NV_BITS == 64
#define MY_FORMAT "%.17"
#elif LU_NV_BITS == 80
#define MY_FORMAT "%.21"
#elif LU_NV_BITS == 128
#define MY_FORMAT "%.36"
#else
#error "LU_NV_BITS not set"
#endif