110/1.1 != 100 floating point issue?

Question

Any thoughts as to that for which I had not accounted here?

Looks like it returns 99.99999999999999

using ruby 2.3.1p112

The answer is in your title. `100-110/1.1` outputs `1.42e-14`, which is probably good enough. — Eric Duminil, Feb 11 '17 at 22:28

score 1 · Answer 1 · edited May 23 '17 at 12:25

1

This was discussed million times - to have precise calculations one must use decimal data type, which in Ruby is represented by BigDecimal class:

BigDecimal(110)/1.1 == 100
#=> true

edited May 23 '17 at 12:25

Community

answered Feb 11 '17 at 22:05

Andrey Deineko

Your summary of the million discussions is very approximative. Decimal is not inherently more accurate than binary. Decimal floating-point is better than binary floating-point for decimal numbers, and multiprecision is better than machine arithmetic, but that does not make BigDecimal the panacea that you imply it to be. – Pascal Cuoq Feb 11 '17 at 22:39

1 Answers1