Re: [boost] [constrained_value] need help with runtime error

Subject: Re: [boost] [constrained_value] need help with runtime error
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2008-12-10 14:45:23

AMDG

Neal Becker wrote:
> This code has an error:
>
> #include <boost/numeric/ublas/vector.hpp>
> #include <boost/constrained_value.hpp>
>
> namespace cv = boost::constrained_value;
> namespace ublas = boost::numeric::ublas;
>
> typedef cv::bounded<int>::type val_t;
> typedef cv::bounded<int>::type::constraint_type constraint_type;
>
> int main() {
>   int min = -200;
>   int max = 200;
>   val_t init (10, constraint_type (min, max));
>   ublas::vector<val_t> v (10, init);
>   ublas::vector<val_t> w = -v;
> }
>
> This code will throw an exception.  The last line invokes:
> ublas/functional.hpp:70 (scalar_negate), which for some reason calls
>
> constrained.hpp:224, which is:
>     constrained(const value_type & v)
>
> That is, initialize only the value, not the constraint!  Any ideas?
>   

It looks like the arithmetic operators may need to be overloaded
rather than relying on implicit conversions?

The error should occur in a simpler case:

val_t x(10, constraint_type(min, max));
val_t neg_x(-x);

In Christ,
Steven Watanabe