{ diff(x1, t) = piecewise(1/2190, k22 = 0, 1/2190)*piecewise(1000, k22 = 0, 1000) - piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7)*piecewise(19, k22 = 0, 19)/(piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7) + piecewise(19, k22 = 0, 19)*(x1 + x3 + x2 + x4))*piecewise(21/100, k22 = 0, 21/100)*x7/(x5 + x6 + x7)*x1 - piecewise(1/2190, k22 = 0, 1/2190)*x1,
  diff(x2, t) = piecewise(2/5, k22 = 0, 2/5)*piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7)*piecewise(19, k22 = 0, 19)/(piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7) + piecewise(19, k22 = 0, 19)*(x1 + x3 + x2 + x4))*piecewise(21/100, k22 = 0, 21/100)*x7/(x5 + x6 + x7)*x1 - (piecewise(1/2190, k22 = 0, 1/2190) + piecewise(1/4, k22 = 0, 1/4))*x2,
  diff(x3, t) = (1 - piecewise(2/5, k22 = 0, 2/5))*piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7)*piecewise(19, k22 = 0, 19)/(piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7) + piecewise(19, k22 = 0, 19)*(x1 + x3 + x2 + x4))*piecewise(21/100, k22 = 0, 21/100)*x7/(x5 + x6 + x7)*x1 - (piecewise(1/2190, k22 = 0, 1/2190) + piecewise(1/4, k22 = 0, 1/4) + piecewise(1/10, k22 = 0, 1/10))*x3,
  diff(x4, t) = piecewise(1/4, k22 = 0, 1/4)*x3 + piecewise(1/4, k22 = 0, 1/4)*x2 - piecewise(1/2190, k22 = 0, 1/2190)*x4,
  diff(x5, t) = (x5 + x6 + x7 - piecewise(1/10, k22 = 0, 1/10)*x7)/(x5 + x6 + x7)*piecewise(1/20, k22 = 0, 1/14)*piecewise(20000, k22 = 0, 4000) - piecewise(33/100, k22 = 0, 1/4)*piecewise(19, k22 = 0, 19)*(x1 + x3 + x2 + x4)/(piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7) + piecewise(19, k22 = 0, 19)*(x1 + x3 + x2 + x4))*(piecewise(7/10, k22 = 0, 7/10)*x3/(x1 + x3 + x2 + x4) + piecewise(3/10, k22 = 0, 3/10)*x2/(x1 + x3 + x2 + x4))*x5 - piecewise(1/20, k22 = 0, 1/14)*x5,
  diff(x6, t) = piecewise(33/100, k22 = 0, 1/4)*piecewise(19, k22 = 0, 19)*(x1 + x3 + x2 + x4)/(piecewise(33/100, k22 = 0, 1/4)*(x5 + x6 + x7) + piecewise(19, k22 = 0, 19)*(x1 + x3 + x2 + x4))*(piecewise(7/10, k22 = 0, 7/10)*x3/(x1 + x3 + x2 + x4) + piecewise(3/10, k22 = 0, 3/10)*x2/(x1 + x3 + x2 + x4))*x5 - (piecewise(1/20, k22 = 0, 1/14) + piecewise(1/14, k22 = 0, 1/14))*x6,
  diff(x7, t) = piecewise(1/10, k22 = 0, 1/10)*x7/(x5 + x6 + x7)*piecewise(1/20, k22 = 0, 1/14)*piecewise(20000, k22 = 0, 4000) + piecewise(1/14, k22 = 0, 1/14)*x6 - piecewise(1/20, k22 = 0, 1/14)*x7 }