test failure for mappers.cc

[Ben Abbott]

John, 

I'm seeing the failure below with tip 11212

        octave:2> test mappers.cc
          ***** assert(arg (single(-1)), single(pi));
        !!!!! test failed
        assert (arg (single (-1)),single (pi)) expected
         3.1416
        but got
         3.1416
        values do not match

The difference between the actual and expected is ...

        arg (single (-1)) - single (pi)
        ans = -2.3842e-07

I consistently get the *exactly* same difference.

        for n = 1:10
          d(n) = arg (single (-1)) - single (pi);
        endfor
        std (d)
        ans = 0

I assume this came about after your mapper changesets. Do you (anyone?) see 
this as well?

Ben