gistfile1.txt

$ python examples/advanced/relativity.py 
Initial metric:
⎡  ν(r)                       ⎤
⎢-ℯ        0    0       0     ⎥
⎢                             ⎥
⎢         λ(r)                ⎥
⎢  0     ℯ      0       0     ⎥
⎢                             ⎥
⎢                2            ⎥
⎢  0       0    r       0     ⎥
⎢                             ⎥
⎢                    2    2   ⎥
⎣  0       0    0   r ⋅sin (θ)⎦
----------------------------------------
Christoffel symbols:
       d       
       ──(ν(r))
       dr      
Γ⁰₁₀ = ────────
          2    
       d       
       ──(ν(r))
       dr      
Γ⁰₀₁ = ────────
          2    

       d         -λ(r)  ν(r)
       ──(ν(r))⋅ℯ     ⋅ℯ    
       dr                   
Γ¹₀₀ = ─────────────────────
                 2          
       d       
       ──(λ(r))
       dr      
Γ¹₁₁ = ────────
          2    
           -λ(r)
Γ¹₂₂ = -r⋅ℯ     
             2     -λ(r)
Γ¹₃₃ = -r⋅sin (θ)⋅ℯ     

       1
Γ²₂₁ = ─
       r
       1
Γ²₁₂ = ─
       r
Γ²₃₃ = -cos(θ)⋅sin(θ)

       cos(θ)
Γ³₂₃ = ──────
       sin(θ)
       cos(θ)
Γ³₃₂ = ──────
       sin(θ)
       1
Γ³₁₃ = ─
       r
       1
Γ³₃₁ = ─
       r
----------------------------------------
Ricci tensor:
         2                               2                                    
        d          -λ(r)  ν(r)   d          -λ(r)  ν(r)   d         -λ(r)  ν(r
      ─────(ν(r))⋅ℯ     ⋅ℯ       ──(ν(r)) ⋅ℯ     ⋅ℯ       ──(ν(r))⋅ℯ     ⋅ℯ   
      dr dr                      dr                       dr                  
R₀₀ = ──────────────────────── + ────────────────────── + ────────────────────
                 2                         4                        r         

                                  
)   d        d         -λ(r)  ν(r)
    ──(λ(r))⋅──(ν(r))⋅ℯ     ⋅ℯ    
    dr       dr                   
─ - ──────────────────────────────
                  4               
           2                                                 2
          d           d          d        d          d        
        ─────(ν(r))   ──(λ(r))   ──(λ(r))⋅──(ν(r))   ──(ν(r)) 
        dr dr         dr         dr       dr         dr       
R₁₁ = - ─────────── + ──────── + ───────────────── - ─────────
             2           r               4               4    
                     d         -λ(r)     d         -λ(r)
                   r⋅──(λ(r))⋅ℯ        r⋅──(ν(r))⋅ℯ     
           -λ(r)     dr                  dr             
R₂₂ = 1 - ℯ      + ───────────────── - ─────────────────
                           2                   2        
                                      2    d         -λ(r)        2    d      
                                 r⋅sin (θ)⋅──(λ(r))⋅ℯ        r⋅sin (θ)⋅──(ν(r)
         2         2     -λ(r)             dr                          dr     
R₃₃ = sin (θ) - sin (θ)⋅ℯ      + ───────────────────────── - ─────────────────
                                             2                           2    

   -λ(r)
)⋅ℯ     
        
────────
        
----------------------------------------
Solve Einstein's equations:
Traceback (most recent call last):
  File "examples/advanced/relativity.py", line 221, in <module>
    main()
  File "examples/advanced/relativity.py", line 214, in main
    l =  dsolve(e, lam(r))
  File "/home/ondrej/repos/sympy/sympy/solvers/ode.py", line 401, in dsolve
    hints = classify_ode(eq, func, dict=True)
  File "/home/ondrej/repos/sympy/sympy/solvers/ode.py", line 746, in classify_ode
    r = _nth_linear_match(reduced_eq, func, order)
  File "/home/ondrej/repos/sympy/sympy/solvers/ode.py", line 2182, in _nth_linear_match
    terms[len(f.args[1:])] += c
KeyError: 2