Ethan Furman <et...@stoneleaf.us> writes: > I will readily admit to not having a maths degree, and so of course to > me saying the integer 123 has a precision of 5, 10, or 99 digits seems > like hogwash to me.
Precision is not a property of the number. It is a property of the *representation* of that number. The representation “1×10²” has a precision of one digit. The representation “100” has a precision of three digits. The representation “00100” has a precision of five digits. The representation “100.00” also has a precision of five digits. Those can all represent the same number; or maybe some of them represent “one hundred” and others represent “one hundred and a millionth”. The representation is only an approximation of the actual number, and the precision tells us how fuzzy the approximation is. None of these say how *accurate* the representation is; if those are representations of the number “seven thousand” they are not very accurate, while they might be passably accurate for the number “one hundred and seventy”. > But I'm always willing to learn. So please explain what 123 with a > precision of five integer digits means, and what to do we gain by > saying such a thing? We gain clarity of speech: we distinguish the different aspects (how many digits of this representation are actually claimed to represent the number?) communicated by a representation. -- \ “… no testimony can be admitted which is contrary to reason; | `\ reason is founded on the evidence of our senses.” —Percy Bysshe | _o__) Shelley, _The Necessity of Atheism_, 1811 | Ben Finney -- https://mail.python.org/mailman/listinfo/python-list
