I think that somewhere the factor with which you multiply is checked
for being -1,0 or 1 and that that causes the problem.
Here is at least an easier way to reproduce the problem
sage: var('y')
y
sage: (y*(-3.0),y*(-2.0),y*(-1.0),y*0.0,y*1.0,y*2.0,y*3.0,y*4.0)
(-3.00000000000000*y, -2.00000000000000*y, -y, 0, y,
2.00000000000000*y, 3.00000000000000*y, 4.00000000000000*y)
sage: 1.0==1
True
On Apr 28, 3:12 pm, kcrisman <
kcris...@gmail.com> wrote:
> sage: var('y,z')
> (y, z)
> sage: x = 4/5*(4*y-3)*z-1/3
> sage: 1.0*x
> 4/5*(4*y - 3)*z - 1/3
> sage: 1.2*x
> 0.960000000000000*(4*y - 3)*z - 0.400000000000000
>
> I'm not familiar enough with the goals of that to be able to say for
> sure. Seehttp://
ask.sagemath.org/question/525/numerical-approximation-for-expr...
> for background.
>
> - kcrisman