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Questions tagged [backslide]

Tag for questions about backslides/backsets/degenerations/degradations/regressions/retrogressions in newer versions of Mathematica, notice this tag isn't for bugs and compatibility issues.

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13 votes
1 answer
226 views

Performance regression for big integer computation

Backslide introduced in 12.0, persisting through 13.1. Recently I noticed that the big integer calculation of the new version is much slower than the old version, can you reproduce, is there a way to ...
expression's user avatar
  • 5,652
4 votes
3 answers
890 views

How can I calculate the sum of this series?

Backslide introduced after 9.0.1, persisting through 13.0. How can I calculate the sum of this series? $\sum_{n=1}^{\infty} \ln \left(1+\frac{1}{n^{2}}\right)$ The sum of this series has been proved ...
lotus2019's user avatar
  • 2,151
9 votes
2 answers
809 views

Numerically solving the KdV equation

Backslide introduced in 9, persisting through 13. I am trying to solve the KdV equation numerically. The following code would work perfectly in version 5: ...
gerald's user avatar
  • 233
7 votes
1 answer
262 views

ImplicitRegion does not work in simple case

Why doesn't this work: RegionPlot[ImplicitRegion[1 == 0.2 x + 0.5 y, {x, y}]], while this, which is almost the same works: ...
ivan's user avatar
  • 175
10 votes
5 answers
725 views

Overflow with NDSolve

Backslide introduced in 10.0, persisting through 12.1. I am trying to solve the following differential equation and plot the result: ...
mattiav27's user avatar
  • 6,757
4 votes
2 answers
194 views

Overflow when using SpheroidalS2

I want to compute the value of the radial oblate spheroidal wave function of the second kind. However, I found the value at small arguments (for example $0.5I$ in the following code) cannot be ...
Jiaxin Zhong's user avatar
11 votes
5 answers
588 views

Mathematica 12 Frontend for Mac: cell grouping messed up upon copy/paste

Bug introduced in 12.0 or earlier and persisting through 13.1 or later The bug is absent in Mathematica 8.0.4 I am not sure whether this has been addressed somewhere already, I couldn't find any ...
Robert Schmidhuber's user avatar
1 vote
1 answer
321 views

Solving system of differential equations in loop with recursive variable

Backslide introduced in 11.3, fixed in 12.0. I've been posting various questions about similar pieces of code all year, so if this looks familiar you may have seen another one of my posts, but this ...
hclb's user avatar
  • 53
3 votes
1 answer
422 views

Singularities forming on boundary while solving system of pde's

Backslide introduced after 9.0.1, fixed in 12.0.1 or earlier. This is a follow up of a previous question I asked regarding solving a system of coupled, non-linear partial differential equations, 2D ...
Woody's user avatar
  • 125
6 votes
1 answer
111 views

Automatic PlotRange based on Interpolation results

Persisting through 11.3, fixed in Mathematica 12.0 We generally use PlotRange->All to see all available points in a plot. But how do you use ...
Rene Duchamp's user avatar
  • 1,419
9 votes
1 answer
316 views

11.3 - import of files with paths containing non-ASCII characters [duplicate]

Import: Version 11.2 works correctly, no problem with non-ASCII characters in the path of file. But upgrated version 11.3 a) does not import these files b) ...
Slepecky Mamut's user avatar
3 votes
1 answer
217 views

Strange rendering of graphics exported as .pdf

Bug introduced in 10.4.1 or earlier and persisting through 12.0 Bug isn't present in version 8.0.4 I am trying to export a graphic generated by the following code to a .pdf file. ...
Neo's user avatar
  • 53
16 votes
2 answers
435 views

Backslide in NSolve in V11.1?

Bug introduced in 11.1.0 and persisting through 11.1.1 In V11.1, NSolve[BesselJ[0, x] == 0 && 0 < x < 20, x] returns no solutions: But in V11.0 (...
Michael E2's user avatar
  • 239k
9 votes
4 answers
435 views

Limit problem no longer works in Mathematica 11.1.0

Backslide introduced in 11.1, fixed in 11.2. In Mathematica 11.0, the following limit, Limit[Power[Sqrt[((1 - 4 n)/(3 n + 2))^(3 n)]^2, (n)^-1], n -> ∞] gave ...
David's user avatar
  • 14.9k
1 vote
2 answers
281 views

NSolve claims there are no solutions in Reals but finds them without restriction to Reals

When trying to answer this question I've discovered what looks like a bug in NSolve introduced in version 11.1.0. $Version <...
Alexey Popkov's user avatar
8 votes
1 answer
311 views

SumConvergence difficulty

Backslide introduced in 9, persisting through 11.2. Consider the series $\sum_{n=1}^\infty\sin\frac{50}{n^2}$. The terms are eventually positive. ...
David's user avatar
  • 14.9k
7 votes
2 answers
416 views

NDSolve with Piecewise solving BVP gives warning bvdisc [duplicate]

Backslide introduced in 9.0, persisting through 11.0.1 I try to solve a boundary value problem of coupled ODEs. For reference, when I solve this set of equations it works without any problems: ...
Eng.Technion's user avatar
7 votes
4 answers
124 views

a Sum that no longer evaluates

Backslide introduced in 7.0, fixed after 11.0, in or before 12.3. At http://forums.wolfram.com/mathgroup/archive/2000/Sep/msg00318.html and http://forums.wolfram.com/mathgroup/archive/1999/Jul/...
Alan's user avatar
  • 13.8k
14 votes
1 answer
244 views

Interesting Progression of ParametricRegion: Bug?

Bug introduced In 10.1 or earlier and fixed 11.1 Consider the following ParametricRegion from an answer to this question: ...
RunnyKine's user avatar
  • 33.2k
17 votes
1 answer
398 views

Why does ImageFilter fail with radius 1, but works with radius 2?

Bug introduced in 9.0 and persisting through 13.1.0 [CASE:3968469] When thinking on a way to answer this question using ImageFilter I have found (with Jason B's ...
Alexey Popkov's user avatar
27 votes
1 answer
361 views

Regression /Bug in DelaunayMesh from 10.3.1 to 10.4

Bug introduced in 10.4 and persists through 11.1 In answering this question, I realized the OP and I were obtaining different results from the alphaShapes2D code. ...
RunnyKine's user avatar
  • 33.2k
19 votes
1 answer
2k views

How to solve the tsunami model and animate the shallow water wave?

Backslide introduced in 9.0, persisting through 13.1. Recently when I was learning differential equations, I noticed there is a shallow water wave equation to model the tsunami propagation. How to ...
LCFactorization's user avatar
4 votes
0 answers
121 views

Why does Solve work in v9.0.1 but not in v10.3.1

I want to solve the following DE $$ P'=k(M-P)P, P[0]=53.08, P[50]=23.192, P[100]=76.212.$$ The Mathematica command is ...
xpaul's user avatar
  • 261
6 votes
1 answer
221 views

This code worked so slow on version 10 but not on earlier version

Backslide introduced after 9.0.1, persisting through 11.3, fixed in 12.0. ...
matrix42's user avatar
  • 7,138
7 votes
1 answer
1k views

Mathematica 10.2 is slow to NIntegrate highly oscillatory integrals

I noticed that Mathematica V10.2 is taking much longer to run my code when compared with V9. One function that seems affected is NIntegrate. For example, for a ...
Frederico's user avatar
9 votes
2 answers
359 views

NSolve finds real-valued results in version 9, but not in version 10

UPDATE Reals also was used in the code. Actually, I tried the following simple piece of code. ...
Shaqpad's user avatar
  • 113
5 votes
1 answer
115 views

Somewhat Irreproducible Integrate Results

Backslide introduced in v10 and persisting through v10.3.1. In the course of considering question 102922, I encountered erratic results from a particular integration. It is illustrated as follows. ...
bbgodfrey's user avatar
  • 61.8k
5 votes
2 answers
228 views

Symbolic integration of SphericalBesselJ

Backslide introduced in v10 and persisting through v10.3.1. Consider the following integral ...
vsht's user avatar
  • 3,527
9 votes
2 answers
440 views

Can your Mathematica do the following integral?

Backslide introduced in v10 and fixed in v10.4.1. I was trying to do the following integral in Mathematica: Integrate[(z-2) PolyLog[2,z]Log[1-z]/z^3,z] What I ...
Nahc's user avatar
  • 455
30 votes
1 answer
385 views

Solve slower in versions 9 and 10

With some systems of equations, Solve is much slower in versions 9 and 10 than in earlier versions, apparently because it is doing more simplification of the ...
Simon Rochester's user avatar
12 votes
2 answers
692 views

Why Mathematica cannot apply The Fundamental Theorem of Calculus automatically?

For some reason Mathematica cannot evaluate this definite integral: ...
Vladimir Reshetnikov's user avatar
29 votes
1 answer
974 views

Why is ListPlot so slow here?

While examining How can I monitor the progress of a Plot? I was surprised to discover that in some cases ListPlot in version 10.0 and 10.1 is orders of magnitude ...
Mr.Wizard's user avatar
  • 272k
48 votes
3 answers
1k views

Is FullGraphics an abandoned function? Is there an alternative?

FullGraphics hasn't worked entirely for a long time and the situation appears to be getting worse instead of better. In Mathematica 10.0, 10.1, 11.3, 12.3 up to 13....
Mr.Wizard's user avatar
  • 272k
29 votes
1 answer
520 views

many indefinite integrals do not evaluate in 10.1, looking for the cause

Bug introduced in 10.1 and fixed in 10.2 Many integrals no longer evaluate in V 10.1 when they did in 10.0.2 Here are some 23 integrals as an example, that all produced results in V 10.0.2, but now ...
Nasser's user avatar
  • 147k
22 votes
4 answers
2k views

Expansion of a hypergeometric function takes ages with Mathematica 9 and 10 (regression?)

Mathematica 8 (Linux version) can evaluate AbsoluteTiming[Series[Hypergeometric2F1[1, 1 - eps/2, 3 - eps, 1/2], {eps, 0, 0}]] in no time. On one of the ...
vsht's user avatar
  • 3,527
8 votes
0 answers
228 views

Regarding Evaluated True

Done a bit of reading: Normal[Series[ ]] does not give a normal expression Regarding the Evaluated->True, consider: ...
David's user avatar
  • 14.9k
25 votes
3 answers
608 views

Backslide of Limit

Backslide introduced in 9.0, and persisting through 12.0. A friend of mine showed me this example: Limit[Sum[Sin[Pi*k/n]/(n + 1/k), {k, 1, n}], n -> Infinity] ...
xzczd's user avatar
  • 67.1k
8 votes
1 answer
4k views

NDSolve and Piecewise functions [duplicate]

Backslide introduced in 9.0, persisting through 11.0.1 I want to clarify upfront, This is not a please help me get the answer to my homework question. I know what I need to do I just do not know how ...
Ajay's user avatar
  • 227
12 votes
3 answers
4k views

Can NDSolve handle discontinuous data?

Backslide introduced in 9.0, persisting through 11.0.1 It is possible to numerically solve a differential equation if not-smooth data are involved? For example the following instruction return the ...
unlikely's user avatar
  • 7,123
26 votes
3 answers
631 views

Performance regression for Fold?

I noticed an over 10x performance drop on Mathematica v9.0.1 (as Oleksandr R. commented, also v8) compared with v7.01 for this code: ...
Yi Wang's user avatar
  • 7,367
36 votes
1 answer
2k views

Mathematica 9 cannot solve this Integral. Mathematica 8 could. Is this a bug?

I was trying to (re)calculate a problem of an older Wolfram blog post (Problem 11457, by M. L. Glasser) with Mathematica 9.0.0.0 (on OS X 10.8.2). ...
Norbert Fabritius's user avatar
3 votes
0 answers
152 views

A recurrence equation that can be solved in version 7 but not in version 8

Backslide introduced in 8.0, fixed at least in 9.0.1. A friend of mine showed me this code sample: ...
xzczd's user avatar
  • 67.1k