I find it very surprising that the conversion would use floating point, since scaled units use static_rational. Are you certain that's how it works?
On Feb 14, 2014, at 8:27 PM, Steven Watanabe <watanabesj@gmail.com> wrote:
AMDG
On 02/14/2014 04:06 PM, Lindley French wrote: <snip> Now, when I cout these values, I see that everything is technically the correct. The problem is that total is a dimensionless quantity which is scaled----it's 1,250,000,000, when I expect 1,250,000, and it displays as "1250000000 m", where m is "milli", not "meters".
What is the correct way to un-scale dimensionless quantities? I tried this: quantity<si::dimensionless,rational<unsigned>> unscaled(total);
However, unscaled still has the same value.
The result comes out as zero for me.
I also tried typedef make_scaled_unit<si::dimensionless, scale<10, static_rational<0> >
::type dimensionless_unit; quantity<dimensionless_unit,rational<unsigned>> unscaled(total);
but this time, unscaled came out zero.
Any suggestions?
The reason it's zero comes down to:
std::cout << rational<unsigned>(1250000000) * 0.001 << std::endl; // prints 0/1
Conversions involving rational do not work correctly, because rational does not support multiplication by double.
In Christ, Steven Watanabe
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