Perform Kahan summation given the total so far, the value to add to the
total, and the error term (which starts at 0.0). Returns the updated total
and the new error term.
Perform Kahan summation given the total so far, the value to add to the
total, and the error term (which starts at 0.0). Returns the updated total
and the new error term.
Kahan's algorithm is a way to sum floating point numbers that reduces
error compared to straightforward addition.