On 31.07.2011 19:13, Nathan Crookston wrote:

Hi Marcel,

On Sat, Jul 30, 2011 at 2:25 PM, Marcel <minusdreidb+boost@gmail.com> wrote:

...

Hi,

I'm new to boost and units and hope this is not too trivial. If I try to multiply a quantity with a dimensionless factor like

quantity<length> a; quantity<length> b = 2.0 * b;

I get compiler errors due to missing operator*. So I worked around this by using

quantity<length> b = quantity<dimensionless>(2.0) * b;

But I'm wondering if there is a easier and better readable way to do this?

Your first example should work -- in fact, the following works for me on g++4 and VC10 (using boost trunk, but should work with all units versions):

#include <boost/units/quantity.hpp> #include <boost/units/systems/si.hpp>

using namespace boost::units;

int main() { quantity<si::length> a; quantity<si::length> b = 2.0 * a;

return 0; }

Perhaps a compilable example, boost version, and compiler would aid diagnosis . . .

HTH, Nate

Hi Nate, thanks for your reply. The example compiles here too in fact, which made me check my actual code more thoroughly: I had used "2" for the factor in my actual code instead of "2.0" as stated in my example. The differing value types seemed to cause the problem. Regards, Marcel