Opened 3 years ago
Last modified 4 weeks ago
#2938 reviewing defect
The parser for symbolic expressions in infix form parses negative numbers and fractions strangly
Reported by: | gkronber | Owned by: | mkommend |
---|---|---|---|
Priority: | medium | Milestone: | HeuristicLab 3.3.17 |
Component: | Problems.DataAnalysis.Symbolic | Version: | trunk |
Keywords: | Cc: |
Description (last modified by gkronber)
Some examples:
- Input: -1.0*x + 2.0
- Expected:
(+ (* -1.0 x) 2.0)
- Output:
(+ (- (* 1.0 x)) 2.0)
- Input: exp(-1.0*x - 2.0)
- Output:
(exp (* -1.0 (+ (* 1.0 x) 2.0)))
- Expected:
(exp (- (* -1.0 x) 2.0))
- Input: 3/3+2/2+1/1
- Output:
((3 * 1/3) + (2 * 1/2) + (1 * 1/1))
Change History (11)
comment:1 Changed 3 years ago by gkronber
- Owner set to gkronber
- Status changed from new to accepted
comment:2 Changed 3 years ago by gkronber
- Description modified (diff)
- Summary changed from The parser for symbolic expressions in infix form parses negative numbers strangly to The parser for symbolic expressions in infix form parses negative numbers and fractions strangly
comment:3 Changed 3 years ago by gkronber
comment:4 Changed 3 years ago by gkronber
- Version set to trunk
r16357: added comments for infix parser tests
comment:5 Changed 3 years ago by gkronber
We can merge r16357 now or move this ticket to the next milestone.
comment:6 Changed 3 years ago by gkronber
- Milestone changed from HeuristicLab 3.3.16 to HeuristicLab 3.3.17
comment:7 Changed 4 weeks ago by gkronber
r18167: changed unit test for InfixParser to actually check the results
comment:8 Changed 4 weeks ago by gkronber
comment:9 Changed 4 weeks ago by gkronber
- Owner changed from gkronber to mkommend
- Status changed from accepted to reviewing
comment:10 Changed 4 weeks ago by gkronber
r18171: fixed a bug in the parser
comment:11 Changed 4 weeks ago by gkronber
r18173: fixed BottomUpSimilarityCalculatorTest because the parser now parses (a - b) as (- a b) instead of (+ a (- b))
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The main problem is that by parsing "-x" as (-1)*x we effectively introduce an additional constant (see non-linear regression). The same issue occurs when parsing "x/y" as "x * 1/y".
Parsing "-3.14" as "(-1)*3.14" is especially strange.