X_iⁿ⁺¹= x_iⁿ + m [ λi (x_i+1ⁿ – 2x_iⁿ + x_i–1ⁿ⁺¹) + b(x_i+1ⁿ –x_i–1ⁿ)²／4] 0< i<N

x_iⁿ⁺¹= x_iⁿ + 2m [ λi (x_i+1ⁿ – x_iⁿ )－h] + bm(h／λi)² i=0 i=0

x_iⁿ⁺¹= x_iⁿ + 2m λi(x_i-1ⁿ – x_iⁿ ) i=N

λ= a+bx

h,m,a,b都已知
请指教。