Hi, On 23 November 2014 at 22:13, Junwei Huang <[email protected]> wrote: > Hi > I am quite new to sympy. I found sympy as I was searching a way to solve a > system of 3 6-order polynomials for 3 unknowns. I tried to solve this system > using either solve_poly_system or solve_triangulated but got the same error. > Here is the part of code: > " > eq1 = 0. > eq2 = 0. > eq3 = 0. > m=0 > for k in range(0,7): > for j in range(0,7-k): > for i in range(0,7-k-j): > if mod(i+j+k,2)==0: > eq1 = eq1 + e1C[m]*p**i*q**j*r**k > eq2 = eq2 + e2C[m]*p**i*q**j*r**k > eq3 = eq3 + e3C[m]*p**i*q**j*r**k > m=m+1 > > #rr = solve_poly_system([eq1, eq2, eq3], p, q, r) > rr= solve_triangulated([eq1, eq2, eq3], p, q, r) > " > e1C, e2C, and e3C are constant coefficients and eq1, eq2, and eq3 are the > three polynomial equations. I got the following error: > > -------------------------------------------------------------------------- > KeyError Traceback (most recent call last > <ipython-input-12-9cbae56e6534> in <module>() > ----> 1 rr = sympy.solve_triangulated([eq1, eq2, eq3], p, q, r) > > /usr/local/lib/python2.7/dist-packages/sympy/solvers/polysys.pyc in > solve_trngulated(polys, *gens, **args) > 263 > 264 """ > --> 265 G = groebner(polys, gens, polys=True) > 266 G = list(reversed(G)) > 267 > > /usr/local/lib/python2.7/dist-packages/sympy/polys/polytools.pyc in > groebner, *gens, **args) > 6380 > 6381 """ > -> 6382 return GroebnerBasis(F, *gens, **args) > 6383 > 6384 > > /usr/local/lib/python2.7/dist-packages/sympy/polys/polytools.pyc in > __new__(s, F, *gens, **args) > 6420 polys[i] = ring.from_dict(poly.rep.to_dict()) > 6421 > -> 6422 G = _groebner(polys, ring, method=opt.method) > 6423 G = [Poly._from_dict(g, opt) for g in G] > 6424 > > /usr/local/lib/python2.7/dist-packages/sympy/polys/groebnertools.pyc in > groeer(seq, ring, method) > 43 seq = [ s.set_ring(ring) for s in seq ] > 44 > ---> 45 G = _groebner(seq, ring) > 46 > 47 if orig is not None: > > /usr/local/lib/python2.7/dist-packages/sympy/polys/groebnertools.pyc in > _buchberger(f, ring) > 236 # ordering divisors is on average more efficient [Cox] page > 111 > 237 G1 = sorted(G, key=lambda g: order(f[g].LM)) > --> 238 ht = normal(h, G1) > 239 > 240 if ht: > > /usr/local/lib/python2.7/dist-packages/sympy/polys/groebnertools.pyc in > normal(g, J) > 102 > 103 def normal(g, J): > --> 104 h = g.rem([ f[j] for j in J ]) > 105 > 106 if not h: > > /usr/local/lib/python2.7/dist-packages/sympy/polys/rings.pyc in rem(f, G) > 1419 c1 = get(m1, zero) - c*cg > 1420 if not c1: > -> 1421 del f[m1] > 1422 else: > 1423 f[m1] = c1 > > KeyError: (0, 0, 7) > ------------------------------------------------------- > eq1, eq2, and eq3 are like this: > In[13]: eq1.simplify() > Out[13]: 5105.00458755661*p**6 - 108.473959633689*p**5*q + > 2402.41285238498*p**5*r + 9008.47267975219*p**4*q**2 - > 1255.39607773283*p**4*q*r + 11277.0701891541*p**4*r**2 - > 1307.26969182159*p**4 + 2011.04932840783*p**3*q**3 + > 4868.72300813206*p**3*q**2*r + 2350.26623001839*p**3*q*r**2 + > 83.2810004274752*p**3*q + 5306.9841358631*p**3*r**3 - > 410.133684217865*p**3*r + 3581.05378966718*p**2*q**4 - > 1494.32987338524*p**2*q**3*r + 9663.32292693404*p**2*q**2*r**2 - > 1603.980521043*p**2*q**2 - 1554.39827080096*p**2*q*r**3 + > 146.877127581136*p**2*q*r + 6189.03791479042*p**2*r**4 - > 1951.0971844993*p**2*r**2 + 104.459609097912*p**2 + 2059.68147982275*p*q**5 > + 2434.36150406603*p*q**4*r + 4573.37297182227*p*q**3*r**2 - > 129.155224299263*p*q**3 + 5326.78736764999*p*q**2*r**3 - > 414.231578475927*p*q**2*r + 2541.58989447865*p*q*r**4 - > 163.881993246563*p*q*r**2 - 7.32935355549153*p*q + 2912.55844639838*p*r**5 - > 459.09272674491*p*r**3 + 16.3862149483427*p*r - 267.46300018096*q**6 - > 251.079215546565*q**5*r - 551.942706049301*q**4*r**2 - 383.602775058541*q**4 > - 518.132756933654*q**3*r**3 + 48.9590425270454*q**3*r - > 281.245218262232*q**2*r**4 - 921.212155372886*q**2*r**2 + > 67.1547741681612*q**2 - 264.01718641355*q*r**5 + 51.0079896560767*q*r**3 - > 2.33274553975296*q*r - 541.968982299977*r**4 + 79.5536696127415*r**2 - > 2.47202741879275 > > In [14]: eq2.simplify() > Out[14]: -533.530507020419*p**6 + 4905.43084014754*p**5*q - > 251.079215546566*p**5*r - 582.162658435345*p**4*q**2 + > 2434.36150406603*p**4*q*r - 1101.00564042678*p**4*r**2 - > 114.412696339151*p**4 + 8753.94762999568*p**3*q**3 - > 1494.32987338524*p**3*q**2*r + 10767.2083390326*p**3*q*r**2 - > 723.759577198517*p**3*q - 518.132756933655*p**3*r**3 + > 48.9590425270454*p**3*r + 2518.77143858425*p**2*q**4 + > 4868.72300813206*p**2*q**3*r + 2371.36169096872*p**2*q**2*r**2 - > 570.416841704303*p**2*q**2 + 5326.78736764999*p**2*q*r**3 - > 414.231578475927*p**2*q*r - 561.023034195364*p**2*r**4 - > 380.66073794717*p**2*r**2 + 29.9539788526177*p**2 + 3767.68958665181*p*q**5 > - 1255.39607773283*p*q**4*r + 9621.24207100615*p*q**3*r**2 - > 610.744183471118*p*q**3 - 1554.39827080096*p*q**2*r**3 + > 146.877127581136*p*q**2*r + 5907.79269652819*p*q*r**4 - > 812.539281619356*p*q*r**2 + 22.3950435470699*p*q - 264.01718641355*p*r**5 + > 51.0079896560767*p*r**3 - 2.33274553975296*p*r + 2559.17857546841*q**6 + > 2402.41285238498*q**5*r + 5653.28315129873*q**4*r**2 - 655.344482123229*q**4 > + 5306.9841358631*q**3*r**3 - 410.133684217865*q**3*r + > 3102.61292867402*q**2*r**4 - 978.100220594949*q**2*r**2 + > 52.3664159395267*q**2 + 2912.55844639838*q*r**5 - 459.09272674491*q*r**3 + > 16.3862149483428*q*r - 271.69327358712*r**4 + 39.8808744205781*r**2 - > 1.23924660588265 > > In [15]: eq3.simplify() > Out[15]: 5638.53509457703*p**5*r + 624.630294795803*p**4*q*r + > 2653.49206793155*p**4*r**2 - 205.066842108932*p**4 + > 10215.2656329833*p**3*q**2*r - 1036.26551386731*p**3*q*r**2 + > 97.9180850540909*p**3*q + 12378.0758295808*p**3*r**3 - > 975.548592249651*p**3*r + 3472.3673313955*p**2*q**3*r + > 5326.78736764999*p**2*q**2*r**2 - 414.231578475927*p**2*q**2 + > 3961.13372056658*p**2*q*r**3 - 272.271365596867*p**2*q*r + > 5825.11689279675*p**2*r**4 - 918.18545348982*p**2*r**2 + > 32.7724298966855*p**2 + 4534.64968247843*p*q**4*r - > 1036.26551386731*p*q**3*r**2 + 97.9180850540908*p*q**3 + > 11253.0949565319*p*q**2*r**3 - 866.875718496121*p*q**2*r - > 1056.0687456542*p*q*r**4 + 204.031958624307*p*q*r**2 - 9.33098215901183*p*q > + 6750.06094898578*p*r**5 - 1083.93796459995*p*r**3 + 39.7768348063708*p*r + > 2826.64157564937*q**5*r + 2653.49206793155*q**4*r**2 - 205.066842108932*q**4 > + 6205.22585734804*q**3*r**3 - 489.050110297474*q**3*r + > 5825.11689279675*q**2*r**4 - 918.18545348982*q**2*r**2 + > 32.7724298966855*q**2 + 3383.85814693625*q*r**5 - 543.386547174239*q*r**3 + > 19.9404372102891*q*r + 3176.57563281193*r**6 - 765.15107460148*r**4 + > 56.1568814642871*r**2 - 1.16333498638407 > > Could anyone please suggest what is causing this error? Is there any other > way of solving this system of polynomial equations in Python? Thanks very > much.
SymPy is unable to detect (floating point) zero, so intermediate polynomials have erroneous terms, causing this error. This is a bug and has to be fixed, thought at this point I'm not sure where exactly the issue occurs. Mateusz > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/f2516e57-6bf9-4d41-b82a-8b788c6024a5%40googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAGBZUCYZmqamux6EEg6ZRJ3HEj2Jcut57guM9kg44vCnXG%2B5zw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
