id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,work_issues,upstream,reviewer,author,merged,dependencies,stopgaps
2857,[with patch; positive review] numerical_approx for matrices,roed,was,"I'm running into problems with coercing to complexes or reals in
matrices:
{{{
 sage: d = matrix([[3, 0],[0,sqrt(2)]])
 sage: b = matrix([[1, -1], [2, 2]])
 sage: e = b * d * b.inverse(); e

 [    1/sqrt(2) + 3/2 3/4 - 1/(2*sqrt(2))]
 [        3 - sqrt(2)     1/sqrt(2) + 3/2]
}}}
and when I try to run n() on the matrix e, I get:
{{{
 sage: e.n()  # or n(e)
 [snip]
 <type 'exceptions.TypeError'>: unable to coerce to a ComplexNumber
}}}

If you take a look at the source code for n(), you'll see that the first thing that it does is to try calling numerical_approx(prec) on the object, and then tries coercing to real or complex fields.  So the solution is to write a method numerical_approx(prec) in the matrix base class that tries to numerically approximate the entries and make a new matrix out of them.",enhancement,closed,major,sage-3.0,linear algebra,fixed,,,,,,,,,