[sage-devel] Bug in solve?
Sage version: 9.8beta3 (built on WSL Ubuntu)
Operating system: Windows 11
I tried to solve a logarithmic equation with solve, using algorithm='sympy':
var("x")
eq = log(x^2) == log(2*x,10)
solve(eq,x,algorithm='sympy')
The result was:
\displaystyle \verb|Complement(ConditionSet(x,|\verb| |\verb|Eq(x**2|\verb|
|\verb|-|\verb| |\verb|(2*x)**(1/log(10)),|\verb| |\verb|0),|\verb|
|\verb|Complexes),|\verb| |\verb|ConditionSet(x,|\verb|
|\verb|Eq(x**(1/log(10)),|\verb| |\verb|0),|\verb| |\verb|Complexes))|
However, using sympy.solve directly
import sympy
var("x")
eq = log(x^2) == log(2*x,10)
sympy.solve(eq,x)
it returns the correct solution
\displaystyle \left[\verb|2**(-1/(1|\verb| |\verb|-|\verb|
|\verb|log(100)))|\right]
Is this a conversion bug into sympy input?
Best
Florian
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Re: [sage-devel] bug in solve?
ok, i got my first mistake,
the first line in the functoin schould be this:
variables = [var("w" + str(i))for i in range(s.nvertices())]
but anyway, no reason for such a big problem.
Am 29.07.2010 01:15, schrieb Johannes:
> i just tried something with solving a equation, i think i did it the
> wrong way, but still it should not result in this:
>
> def calc_wights_by_sum(s)
> variables = var(["w" + str(i) for i in range(s.nvertices())])
> equation = reduce(lambda f1,f2: f1 + f2, [variables[i] * s.vertex(i)
> for i in range(s.nvertices())]) == 0
> print equation
> return solve(equation,variables)
>
> sage: calc_wights_by_sum(s)
> False
> Exception RuntimeError: 'maximum recursion depth exceeded in
> __subclasscheck__' in ignored
> Exception RuntimeError: RuntimeError('maximum recursion depth exceeded
> in cmp',) in Exception RuntimeError: 'maximum recursion depth exceeded
> in __subclasscheck__' in ignored
> ignored
> Exception RuntimeError: 'maximum recursion depth exceeded in
> __subclasscheck__' in ignored
> Exception RuntimeError: RuntimeError('maximum recursion depth exceeded
> in cmp',) in Exception RuntimeError: 'maximum recursion depth exceeded
> in __subclasscheck__' in ignored
> [...]
>
> i just helped to kill python by killall -9 python.
>
> greatz Johannes
>
>
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[sage-devel] bug in solve?
i just tried something with solving a equation, i think i did it the
wrong way, but still it should not result in this:
def calc_wights_by_sum(s)
variables = var(["w" + str(i) for i in range(s.nvertices())])
equation = reduce(lambda f1,f2: f1 + f2, [variables[i] * s.vertex(i)
for i in range(s.nvertices())]) == 0
print equation
return solve(equation,variables)
sage: calc_wights_by_sum(s)
False
Exception RuntimeError: 'maximum recursion depth exceeded in
__subclasscheck__' in ignored
Exception RuntimeError: RuntimeError('maximum recursion depth exceeded
in cmp',) in Exception RuntimeError: 'maximum recursion depth exceeded
in __subclasscheck__' in ignored
ignored
Exception RuntimeError: 'maximum recursion depth exceeded in
__subclasscheck__' in ignored
Exception RuntimeError: RuntimeError('maximum recursion depth exceeded
in cmp',) in Exception RuntimeError: 'maximum recursion depth exceeded
in __subclasscheck__' in ignored
[...]
i just helped to kill python by killall -9 python.
greatz Johannes
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