Is this behavior long-standing? Expected?
Simplify[0. + 1. z, z > 0] (*-> 0.+1.z *) I'm using Mma 11.1. I do not recalling seeing this behavior before. (Bad memory?) It shows up all over the place. E.g.,
eq1 = 2.0 x == y eq2 = x + y == z Solve[eq1 && eq2, {x, y}, Reals] produces
{{x -> 0. + 0.333333 z, y -> 0. + 0.666667 z}} Why are the zero terms (often) not simplified away?
The behavior you discuss in your question has been around as long as I have been using Mathematica. As Michael E2 writes in his comment to the question it results from using inexact quantities in expressions.
Perhaps the following simple function would be of use to you.
fixup[expr_] := expr /. u_ /; Sign[u] == u :> Sign[u] Example of use
fixup[0. + 1. z]
z
fixup[(0. + 1. z)/(0. + 2. z)^2]
0.25/z
fixup[{{x -> 0. + 0.333333 z, y -> 0. + 0.666667 z}}]
{{x -> 0.333333 z, y -> 0.666667 z}}
fixup[expr_] := expr /. u_ /; u == 0 || u == 1 :> Round[u] $\endgroup$
0.is not simplified away because it does not represent an exact zero0. It keeps thePrecisionof the equationMachinePrecision, no matter what happens to the other terms. You can useChopto get rid of it, if desired. (Take care to use an appropriate tolerance.) $\endgroup$