Comment by visarga
> The sum of a set of N numbers is an example of a problem that is not inherently serial.
But addition with floats (not reals) is non associative.
> The sum of a set of N numbers is an example of a problem that is not inherently serial.
But addition with floats (not reals) is non associative.
Using hardware floating point types is not suitable if mathematical correctness matters, and is largely a deprecated practice. Check out Python’s fraction module for example, for exact arithmetic[0].
They didn't say floats, and the sum of a set of floats is not uniquely defined as a float for the rain you stated, at least not without specifying a rounding mode. Most people use "round to whatever my naïve code happens to do" which has many correct answers. To add up a set of floats with only the usual 0.5ULP imprecision, yes, isn't trivial.