python计算牛顿迭代多项式实例分析

''' p = evalPoly(a,xData,x). Evaluates Newton's polynomial p at x. The coefficient vector 'a' can be computed by the function 'coeffts'. a = coeffts(xData,yData). Computes the coefficients of Newton's polynomial. ''' def evalPoly(a,xData,x): n = len(xData) - 1 # Degree of polynomial p = a[n] for k in range(1,n+1): p = a[n-k] + (x -xData[n-k])*p return p def coeffts(xData,yData): m = len(xData) # Number of data points a = yData.copy() for k in range(1,m): a[k:m] = (a[k:m] - a[k-1])/(xData[k:m] - xData[k-1]) return a