double comparisons not working correctly

[pkatta-ktc]

Hello,
I am using double type in c++ for the attached variables Qty1, Qty2, & Qty3.

My expression is: "(Qty1-Qty2+Qty3) = 0 ? Qty1 * 2 : 0"

Mathematically "Qty1-Qty2+Qty3" is zero.

However, this is getting hit by the usual double precision issues. Within muParser when it does the operations "Qty1-Qty2+Qty3" because of how double's behave, the "=" comparison is not working properly.

Outside of muParser I would use arbitrary precision types. How can I ensure proper comparisons within muParser?

Thanks.

[beltoforion]

There is currently no solution for that. It could be fixed easily by changing the implementations of equal and not equals operators to use the usual workaround with fabs and a delta value comparison.