Accuracy of floating point calculations

[Twilight]

On Tuesday, 29 October 2019 at 16:11:45 UTC, Daniel Kozak wrote:
> On Tue, Oct 29, 2019 at 5:09 PM Daniel Kozak 
> <kozzi11 at gmail.com> wrote:
>>
>>
>> If you use gdc or ldc you will get same results as c++, or you 
>> can use C log directly:
>>
>> import std.stdio;
>> import std.math : pow;
>> import core.stdc.math;
>>
>> void main()
>> {
>>      writefln("%12.3F",log(1-0.9999)/log(1-(1-0.6)^^20));
>> }
>
> AFAIK dmd use real  for floating point operations instead of 
> double

Thanks for the clarification. It appears then that because of 
dmd's real calculations, it produces more accurate results, but 
maybe slower. (Calculating the result with the high precision 
calculator at https://keisan.casio.com/calculator agrees with 
dmd.)