Message373328
+1 for changing the language to match the actual mechanics.
> "the sign of the imaginary part of x is used [...]"
I'm trying to see where this happens. Is this part of cmath_sqrt?
if (z.real >= 0.) {
r.real = s;
r.imag = copysign(d, z.imag);
} else {
r.real = d;
r.imag = copysign(s, z.imag);
}
> "continuous from below" and "continuous from above"
> language is misleading;
I'm curious, is that language incorrect? My mental image of a branch cut is a helical graph with the edge cases being continuous from above and below. Likewise, my mental model for branch cut logic is it resolves multiple possible output values in a way preserves continuity from one side or the other.
In other words, I think about branch cuts in terms of continuity rather than sign preservation. Is that incorrect? |
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Date |
User |
Action |
Args |
2020-07-08 18:41:21 | rhettinger | set | recipients:
+ rhettinger, mark.dickinson, docs@python |
2020-07-08 18:41:21 | rhettinger | set | messageid: <1594233681.79.0.0424403730471.issue41245@roundup.psfhosted.org> |
2020-07-08 18:41:21 | rhettinger | link | issue41245 messages |
2020-07-08 18:41:21 | rhettinger | create | |
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