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21
69-3.py
21
69-3.py
@@ -1,8 +1,5 @@
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import math
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list_x = [0.0,0.2,0.4,0.6,0.8]
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list_y = [1.0,1.2214,1.4918,1.8221,2.2255]
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# 定义原函数和其导函数计算结果
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def FxDiff_n(x,n):
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return math.exp(x)
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@@ -22,15 +19,16 @@ def GetDyList(list_y):
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def NewtonForwardRegression(x,n,list_x):
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h = list_x[1] - list_x[0]
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t = (x - list_x[0]) / h
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ks = max([abs(FxDiff_n(list_x[i],n+1)) for i in range(n+1)])
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ks = max([abs(FxDiff_n(list_x[i],n)) for i in range(n)])
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result = 1
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for i in range(n+1):
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for i in range(n):
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result *= (t-i)*h/(i+1)
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return result * ks
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# 牛顿前插
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def NewtonForwardInterpolation(x,n,list_x,list_y):
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list_dyk = GetDyList(list_y)
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print(list_dyk)
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h = list_x[1] - list_x[0]
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t = (x - list_x[0]) / h
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result = list_y[0]
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@@ -57,6 +55,7 @@ def GetDQyList(list_x,list_y):
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# 牛顿基本插值
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def NewtonBaseInterpolation(x,n,list_x,list_y):
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list_dqy = GetDQyList(list_x,list_y)
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print(list_dqy)
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result = list_dqy[0][0]
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mul = 1
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for i in range(1,n):
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@@ -65,7 +64,11 @@ def NewtonBaseInterpolation(x,n,list_x,list_y):
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return result
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if __name__ == '__main__':
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print("三点牛顿前插 e^0.12 结果为%f, 截断误差%f" % NewtonForwardInterpolation(0.12, 2, list_x, list_y))
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print("四点牛顿前插 e^0.12 结果为%f, 截断误差%f" % NewtonForwardInterpolation(0.12, 3, list_x, list_y))
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print("三点牛顿基本插值 e^0.12 结果为%f" % NewtonBaseInterpolation(0.12, 2, list_x, list_y))
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print("四点牛顿基本插值 e^0.12 结果为%f" % NewtonBaseInterpolation(0.12, 3, list_x, list_y))
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list_x = [0.0,0.2,0.4,0.6,0.8] #改成题干的数值##############################3
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list_y = [1.0,1.2214,1.4918,1.8221,2.2255] #改成题干的数值##############################3
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print("三点牛顿前插 e^0.12 结果为%f, 截断误差%f" % NewtonForwardInterpolation(0.12, 3, list_x, list_y))
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print("四点牛顿前插 e^0.12 结果为%f, 截断误差%f" % NewtonForwardInterpolation(0.12, 4, list_x, list_y))
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print("三点牛顿基本插值 e^0.12 结果为%f" % NewtonBaseInterpolation(0.12, 3, list_x, list_y))
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print("四点牛顿基本插值 e^0.12 结果为%f" % NewtonBaseInterpolation(0.12, 4, list_x, list_y))
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#70到73行,0.12改成题干的数值,n是点数################################
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