I have an Asymptote script which computes some values of a pair K. The values are increasing and when the pair below is attained I get a "cygwin exception".

K= (-1.53675691024507e+74,-4.05209495030412e+74)
                                pair G = K / ((1.0, 0.0) - K - K*K);
colorMap4.asy: 107.5: runtime:       0 [asy] asy 713 cygwin_exception::open_stackdumpfile: Dumping stack trace to asy.exe.stackdump 

I don't know what to do with this message. I tried to reinstall Asymptote but I don't have admin rights and there was an error due to forbidden symlinks on my laptop.

Where is this stackdump file? Is it useful ? A number like 4e+74 is not gigantic so why does it crash?

I've just tried to replace the expression of G by dividing the numerator and the denominator by K, to avoid the product K*K. Now the crash has gone but there's another one:

K= (-183907760887.815,-118807190831.258)
C:/PortableApps/Asymptote/plain_shipout.asy: 116.11: Trying to use uninitialized value.
  • Just edited plain_shipout.asy and I added a default filename. We will see. Commented Aug 25, 2023 at 16:23
  • the stackdump will be in the working directory of the asy process which may or may not be the directory with the file. it's useful for some people some of the time, but only if you want to look at system registers in a debugger. (it's just a plain text file so you can look at it, lots of lines like Stack trace: Frame Function Args 0007FFFFA7A0 7FFF4E250947 (0007FFFFA9A8, 000010000002, 000000000002, 0007FFFFDC 10) cygwin1.dll+0x20947 Commented Aug 25, 2023 at 17:33

1 Answer 1


The first problem was indeed a float overflow. By getting rid of K*K, it worked.

For the second problem, I had to modify plain_shipout.asy:

  string prefix="ZOZO"; // this is my modification

Then the program generates ZOZO.eps. Maybe there's another way to give the output name.

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