With the multiplication, after a few minutes, the answer I get is:
[(0, 0, 0),
(0, 1, 0),
(0,
RZZ/RYZ,
(RYZ*RZYI - sqrt(RYZ**2*RZYI**2 + 4*RYZ**2*RZYII - 4*RYZ*RZYII*RZZ))/(2*
RYZ*RZYII)),
(0,
RZZ/RYZ,
(RYZ*RZYI + sqrt(RYZ**2*RZYI**2 + 4*RYZ**2*RZYII - 4*RYZ*RZYII*RZZ))/(2*
RYZ*RZYII)),
(1, 0, 0),
((-RYX + 1)/(RXY*RYX + 1), (RXY + 1)/(RXY*RYX + 1), 0),
((RYX*RZZ - RYZ)/(RXZ*RYX - RYZ),
(RXZ - RZZ)/(RXZ*RYX - RYZ),
(RXZ*RYX*RZYI - RYZ*RZYI - sqrt(4*RXY*RXZ*RYX**2*RZYII*RZZ - 4*RXY*RXZ*RYX
*RYZ*RZYII - 4*RXY*RYX*RYZ*RZYII*RZZ + 4*RXY*RYZ**2*RZYII + RXZ**2*RYX**2*
RZYI**2 + 4*RXZ**2*RYX**2*RZYII - 4*RXZ**2*RYX*RZYII - 2*RXZ*RYX*RYZ*RZYI**2
- 8*RXZ*RYX*RYZ*RZYII + 4*RXZ*RYX*RZYII*RZZ + 4*RXZ*RYZ*RZYII + RYZ**2*RZYI
**2 + 4*RYZ**2*RZYII - 4*RYZ*RZYII*RZZ))/(2*RZYII*(RXZ*RYX - RYZ))),
((RYX*RZZ - RYZ)/(RXZ*RYX - RYZ),
(RXZ - RZZ)/(RXZ*RYX - RYZ),
(RXZ*RYX*RZYI - RYZ*RZYI + sqrt(4*RXY*RXZ*RYX**2*RZYII*RZZ - 4*RXY*RXZ*RYX
*RYZ*RZYII - 4*RXY*RYX*RYZ*RZYII*RZZ + 4*RXY*RYZ**2*RZYII + RXZ**2*RYX**2*
RZYI**2 + 4*RXZ**2*RYX**2*RZYII - 4*RXZ**2*RYX*RZYII - 2*RXZ*RYX*RYZ*RZYI**2
- 8*RXZ*RYX*RYZ*RZYII + 4*RXZ*RYX*RZYII*RZZ + 4*RXZ*RYZ*RZYII + RYZ**2*RZYI
**2 + 4*RYZ**2*RZYII - 4*RYZ*RZYII*RZZ))/(2*RZYII*(RXZ*RYX - RYZ)))]
On Monday, January 16, 2017 at 8:44:56 PM UTC+1, Michele Zaffalon wrote:
>
> Are you missing the multiplication sign in the last line of your
> definition?
> Rz*Z(-Rzz + Rxz*X + Ryz* Y)
>
>
>
>
> On Monday, January 16, 2017 at 3:29:04 PM UTC+1, Alexander Tille wrote:
>>
>> Hi,
>>
>> please have a look at the following code:
>>
>> from sympy import *
>>
>> X,Y,Z = symbols("\X,\Y,\Z")
>>
>> Rxy,Rxz, Ry,Ryx,Ryz, Rz,Rzy,Rzz = symbols("\\RXY,\\RXZ,
>> \\RY,\\RYX,\\RYZ, \\RZ,\\RZY,\\RZZ")
>> Rzy1,Rzy2 = symbols("\\RZYI,\\RZYII")
>>
>> dimensionless_DES_list = [X*(1-X - Ryx*Y),
>> Ry*Y*(1 - Y + Rxy*X + Rzy1*Z - Rzy2*Z*Z),
>> Rz*Z(-Rzz + Rxz*X + Ryz* Y)]
>>
>> equilibria = solve( dimensionless_DES_list,(X,Y,Z))
>>
>> if I execute it I have the following results:
>>
>> Out[3]:
>> [{\Y: 0, \X: 0},
>> {\Y: \RZYI*\Z - \RZYII*\Z**2 + 1, \X: 0},
>> {\Y: 0, \X: 1},
>> {\Y: (\RXY + \RZYI*\Z - \RZYII*\Z**2 + 1)/(\RXY*\RYX + 1),
>> \X: (-\RYX*\RZYI*\Z + \RYX*\RZYII*\Z**2 - \RYX + 1)/(\RXY*\RYX + 1)}]
>>
>> The System is just solved for the Variables X and Y and NOT for Z. What
>> is the reason?
>>
>>
>> I use the following python enviroment.
>> ~$ ipython
>> Python 2.7.12 |Anaconda 4.2.0 (64-bit)| (default, Jul 2 2016, 17:42:40)
>>
>> # packages in environment at /home/atille/.anaconda2:
>> #
>> sympy 1.0 py27_0
>>
>> Thank you in advance.
>> Alex
>>
>
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