examples/differential_equations.py

   1 import sys
   2 sys.path.append("..")
   3
   4 from sympy import Derivative, Symbol, Function, exp, Rational, log, \
   5     dsolve
   6
   7 import relativity
   8
   9
  10 def eq1():
  11     r = Symbol("r")
  12     e = relativity.Rmn.dd(0,0)
  13     e = e.subs(relativity.nu(r), -relativity.lam(r))
  14     print dsolve(e, [relativity.lam(r)])
  15
  16 def eq2():
  17     r = Symbol("r")
  18     e = relativity.Rmn.dd(1,1)
  19     C = Symbol("CC")
  20     e = e.subs(relativity.nu(r), -relativity.lam(r))
  21     print dsolve(e, [relativity.lam(r)])
  22
  23 def eq3():
  24     r = Symbol("r")
  25     e = relativity.Rmn.dd(2,2)
  26     e = e.subs(relativity.nu(r), -relativity.lam(r))
  27     print dsolve(e, [relativity.lam(r)])
  28
  29 def eq4():
  30     r = Symbol("r")
  31     e = relativity.Rmn.dd(3,3)
  32     e = e.subs(relativity.nu(r), -relativity.lam(r))
  33     print dsolve(e, [relativity.lam(r)])
  34
  35 eq1()
  36 eq2()
  37 #eq3()
  38 #eq4()