Hi. Your expression is rather complicated, but as far as I can tell, you did find a bug. Can you report it in our issue tracker (http://code.google.com/p/sympy/issues/list)? Also, if you can find a simpler expression that exhibits the same problem, that would help a lot too.
By the way, you don't need to define variables that you are going to assign things to (your first var()). And also, you forgot to include Re in your var calls. Aaron Meurer On Thu, Jun 23, 2011 at 11:20 AM, Kemelli <[email protected]> wrote: > > Hello! > I think I found a bug on collect. Can anyone tell me, please, if > either it is indeed a bug or I am doing something wrong? > Thanks a lot! > > var('Q3,Q3n,R3') > var('twopi_invLx twopi_invLy twopi_invLz', real=True) > var(""" > a_u0,a_ux,a_uxy,a_uxz,a_uy,a_uyz,a_uz,b_ux,b_uxy,b_uxz,b_uy,b_uyz,b_uz, > c_ux,c_uxy,c_uxz,c_uy,c_uyz,c_uz, d_uxy,d_uxz,d_uyz, > e_uxy,e_uxz,e_uyz, f_u0,f_ux,f_uxy,f_uxz,f_uy,f_uyz,f_uz, > g_u0,g_ux,g_uxy,g_uxz,g_uy,g_uyz,g_uz""",real=True) > var(""" > a_v0,a_vx,a_vxy,a_vxz,a_vy,a_vyz,a_vz,b_vx,b_vxy,b_vxz,b_vy,b_vyz,b_vz, > c_vx,c_vxy,c_vxz,c_vy,c_vyz,c_vz, d_vxy,d_vxz,d_vyz, > e_vxy,e_vxz,e_vyz, f_v0,f_vx,f_vxy,f_vxz,f_vy,f_vyz,f_vz, > g_v0,g_vx,g_vxy,g_vxz,g_vy,g_vyz,g_vz""",real=True); > var(""" > a_w0,a_wx,a_wxy,a_wxz,a_wy,a_wyz,a_wz,b_wx,b_wxy,b_wxz,b_wy,b_wyz,b_wz, > c_wx,c_wxy,c_wxz,c_wy,c_wyz,c_wz, d_wxy,d_wxz,d_wyz, > e_wxy,e_wxz,e_wyz, f_w0,f_wx,f_wxy,f_wxz,f_wy,f_wyz,f_wz, > g_w0,g_wx,g_wxy,g_wxz,g_wy,g_wyz,g_wz""",real=True) > > > > Q3=-(a_uz*b_uz**3*twopi_invLz**3*cos(g_uz + f_uz*t)*sin(c_uz + > b_uz*twopi_invLz*z) - a_wx*b_wx**3*twopi_invLx**3*cos(g_wx + > f_wx*t)*sin(c_wx + b_wx*twopi_invLx*x) + > a_uxz*d_uxz**3*twopi_invLz**3*cos(g_uxz + f_uxz*t)*cos(c_uxz + > b_uxz*twopi_invLx*x)*sin(e_uxz + d_uxz*twopi_invLz*z) + > a_uyz*d_uyz**3*twopi_invLz**3*cos(c_uyz + > b_uyz*twopi_invLy*y)*cos(g_uyz + f_uyz*t)*sin(e_uyz + > d_uyz*twopi_invLz*z) - a_wxy*b_wxy**3*twopi_invLx**3*cos(g_wxy + > f_wxy*t)*cos(e_wxy + d_wxy*twopi_invLy*y)*sin(c_wxy + > b_wxy*twopi_invLx*x) - a_wxz*b_wxz**3*twopi_invLx**3*cos(g_wxz + > f_wxz*t)*cos(e_wxz + d_wxz*twopi_invLz*z)*sin(c_wxz + > b_wxz*twopi_invLx*x) + > a_uxz*d_uxz*twopi_invLz*b_uxz**2*twopi_invLx**2*cos(g_uxz + > f_uxz*t)*cos(c_uxz + b_uxz*twopi_invLx*x)*sin(e_uxz + > d_uxz*twopi_invLz*z) + > a_uyz*d_uyz*twopi_invLz*b_uyz**2*twopi_invLy**2*cos(c_uyz + > b_uyz*twopi_invLy*y)*cos(g_uyz + f_uyz*t)*sin(e_uyz + > d_uyz*twopi_invLz*z) - > a_wxy*b_wxy*twopi_invLx*d_wxy**2*twopi_invLy**2*cos(g_wxy + > f_wxy*t)*cos(e_wxy + d_wxy*twopi_invLy*y)*sin(c_wxy + > b_wxy*twopi_invLx*x) - > a_wxz*b_wxz*twopi_invLx*d_wxz**2*twopi_invLz**2*cos(g_wxz + > f_wxz*t)*cos(e_wxz + d_wxz*twopi_invLz*z)*sin(c_wxz + > b_wxz*twopi_invLx*x))/Re > > > Q3n=expand(Q3) > Q3n=collect(Q3n,[twopi_invLx**3/Re,twopi_invLz**3],exact=True) > > R3=Q3-Q3n > R3=expand(R3) > > R3==0 #this should be true, but it is not. > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
