Timeline for Using Simplify on a consistent system returns False
Current License: CC BY-SA 3.0
27 events
| when toggle format | what | by | license | comment | |
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| Jun 16, 2020 at 9:23 | history | edited | CommunityBot |
Commonmark migration
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| Oct 30, 2015 at 20:30 | history | edited | Szabolcs | CC BY-SA 3.0 |
deleted 25 characters in body
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| Oct 30, 2015 at 20:21 | history | edited | Pillsy | CC BY-SA 3.0 |
added 7 characters in body
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| Oct 30, 2015 at 20:12 | comment | added | Michael E2 | @Pillsy You can fix the header if you like. My institution still hasn't gotten around to letting us upgrade yet, so I can't check it myself. :/ | |
| Oct 30, 2015 at 20:06 | comment | added | Pillsy | Looks like it's been fixed as of 10.3 | |
| Jul 29, 2015 at 12:54 | history | edited | Michael E2 | CC BY-SA 3.0 |
Bug information
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| Jun 29, 2015 at 18:38 | vote | accept | Michael E2 | ||
| Jun 29, 2015 at 18:38 | history | edited | Michael E2 | CC BY-SA 3.0 |
Added confirmation
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| Jun 26, 2015 at 7:48 | history | edited | Mr.Wizard | CC BY-SA 3.0 |
make header more uniform with other posts
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| Jun 25, 2015 at 22:54 | comment | added | Michael E2 |
@Dr.WolfgangHintze I think it fails whenever x^2 == z for any negative, real, numeric z and works correctly on all else. E.g. your a, -Infinity, I or -I, etc. all work correctly. But not x^2 == -GoldenRatio etc. It also works correctly on (x+1)^2 == -1. So far, the bug seems confined to a very narrow range of examples, but perhaps not a very uncommon examples.
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| Jun 25, 2015 at 22:44 | comment | added | Dr. Wolfgang Hintze | I don't know if someone has mentioned already that (1) Simplify[y==0&&x^2== a] with an unspecified symbol "a" returns the argument unchanged, and hence Simplify[y==0&&x^2== a]/.a->-1 gives what is to be expected. (2) Simplify[y == 0 && x^2 == -1 + x] replies correctly although x cannot be real. (3) it seems that any possible way to express the constant 1 (Sin[pi/2], Exp[0], Sqrt[1], ...) leads to the same false result. (4) x^2=I works out fine. | |
| Jun 25, 2015 at 22:44 | history | edited | Michael E2 | CC BY-SA 3.0 |
Added bug info
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| Jun 25, 2015 at 22:42 | comment | added | Michael E2 | It works correctly in V7. Incorrectly in V9.0.1. So it seems the bug was introduced in V8 and persists through V10.1. (Please correct if I'm mistaken.) | |
| Jun 25, 2015 at 22:28 | comment | added | Dr. Wolfgang Hintze | @ Jens : you will surely benefit from following my hint to 5.2. I noticed in several occasions that that was a very good version, especially I don't want to miss it in Integrate[] where it has often higher performance than 8 and 10. | |
| Jun 25, 2015 at 19:20 | comment | added | Jens | @SjoerdC.deVries I just added the bugs tag since people seem to agree. | |
| Jun 25, 2015 at 19:20 | history | edited | Jens |
Added bugs tag after 2 upvotes on my answer.
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| Jun 25, 2015 at 19:18 | comment | added | Sjoerd C. de Vries | Shall we add the bugs tag? | |
| Jun 25, 2015 at 18:33 | comment | added | Michael E2 | @Jens Thanks for investigating the issue. I have reported it just now. | |
| Jun 25, 2015 at 17:40 | answer | added | Jens | timeline score: 6 | |
| Jun 25, 2015 at 17:23 | comment | added | Jens |
@Dr.WolfgangHintze I just restored version 5.2 and can confirm that Simplify leaves the expression unchanged there (on Mac OS X). This seems to indicate that the bugs tag is warranted here, and it should be reported to Wolfram.
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| Jun 25, 2015 at 17:11 | comment | added | Jens | @Dr.WolfgangHintze Very interesting. Now I regret that I deleted version 5.2 just a few weeks ago... | |
| Jun 25, 2015 at 7:45 | comment | added | Dr. Wolfgang Hintze | In version 5.2 (which I luckily still keep) there's no problem Simplify[y == 0 && x^2 == -1] (* y == 0 && x^2 == -1 *). Hence we notice a "regression" from 5.2 to 8 and 10. | |
| Jun 25, 2015 at 6:45 | history | tweeted | twitter.com/#!/StackMma/status/613961247185338368 | ||
| Jun 25, 2015 at 6:37 | comment | added | Bob Hanlon |
The problem does not appear if the equations are entered as a list: Simplify[{y == 0, x^2 == -1}]
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| Jun 25, 2015 at 5:37 | comment | added | Jens |
The same happens in version 8. And it also happens with Simplify[x^2==-1||y^2==-1], as if the variables are inexplicably assumed to be real. I agree this shouldn't happen.
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| Jun 25, 2015 at 4:47 | history | edited | Michael E2 | CC BY-SA 3.0 |
Added version/system info
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| Jun 25, 2015 at 4:25 | history | asked | Michael E2 | CC BY-SA 3.0 |