tri gates mutate: show the boundary survivors, do not rate them (Refs #2161) - #2634
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#2630 established that the boundary column's denominator holds two populations -- comparisons that decide a verdict, and loop bounds and display cutoffs that cannot -- and that no line-local filter separates them, because a kill is the only proof of verdict-reachability and the filter removed proven kills. That leaves the column unreadable rather than wrong. `SURVIVED at boundary lines 45, 91, 214, 223, 226, 409` gives a reader nothing to act on. Two changes, neither touching the measurement. Print the source beside the line number, for this operator only: 91 `if len(out) > 6:` a display cutoff 214 `while len(v) < N:` a loop bound 226 `while j < len(src):` a scan bound 223 `if b < 0:` the only one worth reading Five of six classify themselves at a glance. The reader does the separation the tool cannot, in seconds rather than by opening the file. And say what the denominator is, in the summary, only when this operator ran -- so killed/total is not read as a rate. The rule: when a metric mixes populations you cannot separate, do not report a ratio; report the members. A rate over a mixed denominator invites exactly the conclusion this command exists to prevent, and invites it most from whoever computed it. The killed count keeps its meaning: a LOWER BOUND, established after the fact, on how many comparisons reach a verdict. Smaller than a percentage, and true. 194 tests pass. Refs #2161
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* gft encoder: pin the smallest normal binade `if off < 0: return 0` survived the boundary operator. Printing the source beside the line number (#2634, yesterday) showed it is not a loop bound. `off = e + 40` is ZERO in the smallest normal binade, [2^-40, 2^-39). With `<=`, every value there encodes as 0 -- which is the ZERO SENTINEL. A non-zero magnitude silently reported as zero, in the encoder every trained weight passes through. The exact power 2^-40 is NOT a witness: its mantissa is 0, so it already encodes as 0 and the mutant changes nothing there. A witness needs a non-zero mantissa in that binade, so the pin is 1.5*2^-40, which encodes 256 and would become 0. Three assertions: the magnitude, the sign, and the value one binade below which IS legitimately zero. Negative control: with `<=` planted the tool exits 1 on the new assertion naming it; restored, 0. Nothing else in this file reaches that binade -- every value the training self-tests encode sits many binades higher, which is why the mutant lived. This also corrects a generalization I made yesterday. Of the four `if x < 0:` sites across the tools, only the `find()` idiom in verify_igla_race is equivalent (find returns -1 or an index, and every caller passes a match start whose first character is a keyword). The other three -- this one, `d < 0` in _magsub, and `end < 0` after rfind in diffbin -- are real boundaries where 0 is a valid value. "Boundary survivors are loop bounds" was too broad. Refs #2161 * skill: a surviving boundary was real, and the boundary value was not its witness (Refs #2161)
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#2630 established that the boundary column's denominator holds two populations — comparisons that decide a verdict, and loop bounds and display cutoffs that cannot — and that no line-local filter separates them, because a kill is the only proof of verdict-reachability and the filter removed proven kills.
That leaves the column unreadable rather than wrong.
SURVIVED at boundary lines 45, 91, 214, 223, 226, 409gives a reader nothing to act on.Two changes, neither touching the measurement
Print the source beside the line number, for this operator only:
Five of six classify themselves at a glance. The reader does the separation the tool cannot, in seconds rather than by opening the file.
Say what the denominator is, in the summary, only when this operator ran — so
killed/totalis not read as a rate.The rule
When a metric mixes populations you cannot separate, do not report a ratio — report the members. A rate over a mixed denominator invites exactly the conclusion this command exists to prevent, and invites it most from whoever computed it.
The killed count keeps its meaning either way: a lower bound, established after the fact, on how many comparisons reach a verdict. Smaller than a percentage, and true.
194 tests pass. §109.
Refs #2161