20191016 02:05:55 0500  commented answer  Sage stalls during computation @tomteil 2692 iterations, well over a day, and still going. We can safely say that with Coin it does not stall. However, using Coin would be a significant stepdown because its worse performance. I am still puzzled about why there is no performance difference on your computer. 
20191014 14:36:23 0500  commented answer  Sage stalls during computation @tmonteil Wow, that's weird! Do you have any idea what could explain this difference? I verified that only a single CPU core is in use with both. I am using Sage 8.9, built from source without changing any options. The solutions that both GLPK and Coin return seem to be the same ones that you quote. I also tried the calculation with GLPK on a Mac laptop (where I have not yet managed to install CBC), and it took 20 seconds, which is consistent with the 27 s timing I got on the Linux machine. Why would it be taking a full minute on your computer? P.S. It does not look like it's going to stall with Coin, but let me keep it running for 24 hrs to be sure. 
20191014 10:53:59 0500  commented answer  Sage stalls during computation @tomteil It's running, I'll let you know. In the meantime, could you please try if 
20191014 06:05:00 0500  commented answer  Sage stalls during computation @tmonteil You are right that the code of 
20191014 05:56:52 0500  commented answer  Sage stalls during computation 
20191014 05:52:29 0500  commented answer  Sage stalls during computation @david Yes, I am sure. If I run 
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20191013 04:59:34 0500  commented question  Sage stalls during computation @tmonteil It's not because of a specific graph. The stalling appears to be random. I know this because I normally run this on a set of precomputed graphs, so I could easily retry on the graph where it stalled. Also, running it twice on the same data won't stall at the same step. 
20191012 13:04:00 0500  commented answer  Sage stalls during computation @tmonteil I added a minimal example. Can you try to reproduce the problem? 
20191011 13:18:18 0500  commented answer  Sage stalls during computation Some comments on 
20191011 13:07:27 0500  commented answer  Sage stalls during computation Sure—I'll get back to you when I have a small example that reliably fails. It'll take time as it usually takes hours for it to fail. 
20191011 12:57:21 0500  commented answer  Building Sage 8.9 from source fails I asked libreadlinedev, libncurses5dev and libncursesw5dev to be installed on this computer. Now Sage 8.9 compiles successfully. libreadlinedev alone was not sufficient. I did this based on the linked Google Groups thread before Dima posted here. 
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20191011 10:57:00 0500  commented answer  Building Sage 8.9 from source fails Checking the log file more carefully revealed this line:

20191011 10:48:57 0500  commented answer  Building Sage 8.9 from source fails It fails with the same message. The output of

20191011 10:37:57 0500  commented answer  Building Sage 8.9 from source fails

20191011 06:06:28 0500  asked a question  Building Sage 8.9 from source fails I am trying to build Sage 8.9 from source on Linux (Ubuntu 16.04, gcc 6). It fails. I could build Sage 8.8 on the same machine without problems. It says that python2 and python3 failed to build, and suggests to look at the log files. The log files contain: and Has anyone experienced the same and is there a simple solution? Unfortunately, I do not have root access myself, thus I can't quickly try to install the readline dev package. 
20191011 04:00:38 0500  commented answer  Sage stalls during computation It is not that trivial to boil down the code to a minimal example. If I put in the work to do that, would you be willing to try to reproduce the problem? Trying to reproduce would also be some trouble: It would involve leaving Sage running for up to a day (or running multiple Sage processes for several hours to increase the likelihood that one of them would stall). 
20191011 02:27:37 0500  asked a question  Sage stalls during computation I was using SageMath 8.8's feedback_edge_set function on a large dataset. The calculation would take a couple of days to finish. Unfortunately, Sage would keep stalling every few hours. The CPU usage of the process would simply drop to zero, and it would stop doing anything. I had to kill the process (a simple Has anyone else experienced this? Is it a known problem? Is there a workaround? It is very frustrating to have to keep manually killing and restarting the process. This problem also prevents me from running a calculation overnight: in the morning I might find that it stopped merely an hour after I started it (if I'm unlucky). More information:
Minimal example: Put this in a source file: Run it as In my last test, it took 291 iterations and ~45 hours before it stalled. It appears to stall only when GLPK is used as the MIP solver (i.e. 
20191011 02:18:03 0500  commented answer  Sage takes very long to start—why? And with Sage 8.8 and Sage 8.9 too ... 
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20190301 07:09:23 0500  commented answer  Importing Python packages into Sage or Vice Versa This does not work for the same reason edenharder said. I am using Sage on macOS, and Sage is supposed to be fully selfcontained. It should contain all libraries needed. The problem is not that the OS is missing them. 
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20190225 07:09:24 0500  commented question  Sage takes very long to start—why? @Juanjo There is no entry in the log that looks relevant. The entries start appearing only after it has started up. Also: I think you misunderstood me: it does not get stuck on the "currently starting" page. That page does not even appear until a couple of minutes after the app was started. Once that page appears at all, everything is fast. 
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20190219 08:16:22 0500  asked a question  Sage takes very long to start—why? I am using the app version of Sage on macOS 10.14.3. Both version 8.5 and 8.6 take very long to start up. As I remember, previous versions were fine. Does anyone else experience this problem (on the same OS with the same versions) and is there a simple solution? How can I debug what is happening? By "slow to start" I mean that after starting the app, nothing at all happens for 12 minutes (!). Only _after_ that do I see a browser window with "The SageNB server or Jupyter is currently starting". The command line executable 
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20150326 22:09:36 0500  marked best answer  How to plot histogram from list? Given a list of numbers, such as Clarification: 5, 3, 6, 1, ... should not be used for the heights of bars. Instead, the data should be binned first to create a histogram. Given a list of pairs, such as Clarification: How can I use a colour scheme in 
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20141116 18:36:57 0500  marked best answer  How to simplify with Sage? Does Sage have a function to simplify symbolic expressions in a similar way to how the other major CAS do it? I.e. use heuristics to try to come up with a form which is likely to seem simpler to humans, which is certainly subjective and cannot be done perfectly, but it's also certainly very useful.
I'm sure there must be a function that does this, as I beieve Sage includes several good CAS, I just can't find it. Some examples to try: (Second one taken from Mathematica documentation.) I know I can play with 