scripts/EP1 10.03 Coupled Pendulums.LACE

   1 # 2 coupled pendulums
   2 # x1'' = -k1*x1 + k*(x2-x1)
   3 # x2'' = -k2*x2 - k*(x2-x1)
   4 # xi are the displacement of the pendulum to its resting position
   5
   6 coefficient.1 -> k1
   7 coefficient.2 -> k2
   8 coefficient.3 -> k
   9 coefficient.5(-1) -> -x10 # initial displacement x1
  10 coefficient.6(-1) -> -x20 # initial displacement x2
  11
  12 iintegrate x1'' -> -x1'
  13 iintegrate -x1' -> x1
  14   IC: -x10
  15
  16 iintegrate x2'' -> -x2'
  17 iintegrate -x2' -> x2
  18   IC: -x20
  19
  20 cmultiply x1, k1 -> k1*x1
  21 cmultiply x2, k2 -> k2*x2
  22
  23 invert x1 -> -x1
  24 isum x2, -x1 -> -(x2-x1)
  25 cmultiply -(x2-x1), k -> -k*(x2-x1)
  26
  27 isum k1*x1, -k*(x2-x1) -> -k1*x1+k*(x2-x1)
  28 assign -k1*x1+k*(x2-x1) -> x1''
  29 invert -k*(x2-x1) -> k*(x2-x1)
  30 isum k2*x2, k*(x2-x1) -> -k2*x2-k*(x2-x1)
  31 assign -k2*x2-k*(x2-x1) -> x2''
  32
  33 output x1 -> out.x
  34 output x2 -> out.y