ASKSAGE: Sage Q&A Forum - Latest question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 25 Sep 2019 11:42:43 -0500Stack overflow in boolean testhttp://ask.sagemath.org/question/48058/stack-overflow-in-boolean-test/Using SageMath 8.8, I encountered a strange error involving boolean tests. The following code reproduces the issue:
x, y = var('x, y')
assume(x>0)
assume(y>0)
bool(y*(x-y)==0)
`RuntimeError: ECL says: C-STACK overflow at size 1048576. Stack can probably be resized.
Proceed with caution.`
This code should obviously return `False`. Changing `y*(x-y)` to `x*(y-x)` indeed returns `False`, which means `x` and `y` cannot be exchanged. Without the assumptions, the code works as expected.
I initially thought it was due to my Sage installation, but running this code on https://sagecell.sagemath.org/ also produces asymmetric behavior, though no error comes out (just a blank answer).
Is this a known issue ? Can someone reproduce this ?Florentin JaffredoWed, 25 Sep 2019 11:42:43 -0500http://ask.sagemath.org/question/48058/How to increase ECL/maxima memory limits in SageMath?http://ask.sagemath.org/question/47203/how-to-increase-eclmaxima-memory-limits-in-sagemath/ I am looking for a symbolic solution of a linear system 10x10. The coefficients and the right-hand sides are symbolic expressions, and it is critical for my. After one hour run with ~5 GB memory consumption I get an error message:
"TypeError: ECL says: Memory limit reached. Please jump to an outer pointer, quit program and enlarge the memory limits before executing the program again."
My Windows-10 PC has 64 GB, so it is definitely not the physical memory limitation. According to my Google search results, there are deliberately tight default memory limits in the Embeddable Common Lisp (ECL), which is used in Maxima. This page
"https://trac.sagemath.org/ticket/6772"
suggests to increase the ECL heap size to 1 GB by adding a line
"(ext:set-limit 'ext:heap-size (* 1024 1024 1024))"
to the file "maxima/src/ecl-port.lisp". I have found this file under "C:\Program Files\SageMath 8.7\runtime\opt\sagemath-8.7\local\share\maxima\5.41.0\src" and added such line with the 8 GB limit (* 2048 2048 2048). This had absolutely no effect, the same error message appeared after the same run time.
I see two such questions answered in this forum. However both answers suggest to reformulate the original problem, which is not what I need. I will appreciate an explanation of how to increase the ECL memory limits in SageMath. Is there something like ".eclrc" configuration file in SageMath? May be, I have to install Maxima standalone and try it there?SevasThu, 18 Jul 2019 04:15:50 -0500http://ask.sagemath.org/question/47203/What does "Runtime Error: ECL says: ... is not of type FIXNUM" mean and how to fix it?http://ask.sagemath.org/question/10908/what-does-runtime-error-ecl-says-is-not-of-type-fixnum-mean-and-how-to-fix-it/I am trying to integrate $x(0.6x^{0.5}+0.6)$ from $0$ to 1.
Here's what I tried:
var('x')
(x*(0.6*x^0.5+0.6)).integrate(x,0,1)
But I received the following error:
RuntimeError: ECL says: 3.0 is not of type FIXNUM.
What does the error mean (I am especially curious where the 3 came from) and what can I do to correctly evaluate the definite integral? According to Wolfram Alpha, the answer is 0.54.ensabaMon, 13 Jan 2014 03:42:37 -0600http://ask.sagemath.org/question/10908/Problems with LaPlace transform when 'a' is negative in e^-athttp://ask.sagemath.org/question/8908/problems-with-laplace-transform-when-a-is-negative-in-e-at/ var('s t')
f = t^(-1)*exp(-t)-t^(-1)*exp((-3)*t)
f.laplace(t,s)
The above transform works as expected, however, when (-3) is changed to (3), I get the following error:
Traceback (click to the left of this block for traceback)
...
TypeError: ECL says: Maxima asks: Is s-3 positive, negative, or zero?
The Solution that I am expecting is:
log((s - 3)/(s + 1))
I don't know how to specify if s-3 is positive, negative, or zero. Any ideas?
Thanks,
Taylor Killian
tkillianThu, 19 Apr 2012 17:39:03 -0500http://ask.sagemath.org/question/8908/