如何修复列表长度的错误？

Question

请帮帮我！ 在 3-rd 这一步我得到了这样的错误

Part 41 of ...... does not exist.

虽然在前面的步骤中它起作用并返回了结果。我在 spkn、spkw、spmn、spmw 和 [=36] 中有 lists 个 40 个元素=]41 在 spx,spfn,spfw.

代码：

spx = {-2, -1.90577, -1.81153, -1.59327, -1.375, -1.35785, -1.3407, -1.24655, -1.22941, -1.11811, -0.934054, -0.80167, -0.75, -0.625,-0.5, -0.25, -0.0981238, 0.303752, 0.651876, 0.94833, 1, 1.5, 1.75,2.11731, 2.5, 2.5625, 2.625, 3.3125, 3.75, 4, 4.00964, 4.01928,4.25964, 4.36731, 4.5, 4.75, 5, 5.25, 5.5, 5.75, 6}
spkw = {105.056, 89.2249, 17.7361, 7.25929, 7.25929, 7.25929, 7.25929,1.09386, 1.09386, -7.35382, -12.5073, -11.929, -11.929, -15.429, -8.63312,-6.34314, -14.3807, -16.7907, -18.933, -12.3896, -3.021, -22.0262,-25.7865, -18.8033, -9.07591, -9.18036, -8.49959, -9.24378, -7.32337,-0.271835, -0.270096, 0.123206, 0.156523, 0.465142, 4.12922, 4.23318,8.03654, 8.20981, 12.1518, 12.3944}
spkn = {73.5426, 66.8007, 24.6942, 16.4029, 0.726929,0.314512, -1.23002, -1.23002, -3.90668, -10.8276, -14.2065,-13.0895, -18.656, -20.1709, -8.79676, -8.79676, -11.2319, -13.9771, -15.1407, -2.50312, -4.72374, -32.4496, -34.2958, -21.0455, -2.45882,-2.45882, -2.45882, -2.45882, -2.45882, -2.45882, -2.45882, -1.70357, -1.70357, -1.11799, 6.1251, 6.36752, 6.36752, 6.60995, 14.0955,14.5803}
spmw = {243.475, 213.305, 83.8004, 67.1081, 67.1081, 67.1081, 67.1081,59.4226, 59.4226, 49.9772, 45.1635, 45.6272, 45.6272, 43.4397,46.8376, 47.4101, 46.6214, 47.3535, 48.75, 42.5447, 33.1761,61.6839, 68.2644, 53.4787, 29.1603, 29.4279, 27.6409,30.1061,22.9045,-5.30161,-5.30859,-6.88938,-7.0313,-8.37913,-24.8675,-25.3613, -44.3781, -45.2877, -66.9686, -68.3634}
spmn = {180.448, 167.6, 91.3225, 78.1123, 56.5579, 55.9978, 53.9271,53.9271, 50.6364, 42.898, 39.742, 40.6374, 36.4626, 35.5158,41.2028, 41.2028, 40.9639, 41.7978, 42.5563, 30.5716, 32.7923,74.3811, 77.6119, 49.5569, 3.09017, 3.09017, 3.09017, 3.09017,3.09017, 3.09017, 3.09017, 0.0546329, 0.0546329, -2.5028,-35.0967, -36.2482, -36.2482, -37.5209,-78.6912, -81.4791}
spfn[[i]] = spkn[[i]]*spx[[i]] + spmn[[i]];
spfw[[i]] = spkw[[i]]*spx[[i]] + spmw[[i]];
spfw = {33.3632, 43.263, 51.6709, 55.5421, 57.1266, 57.2511, 57.3756,58.059, 58.0778, 58.1995, 56.846, 55.1903, 54.5739, 53.0828,51.1542, 48.9959, 48.0325, 42.2533, 36.408,30.7952,30.1551,28.6446,23.138,19.4168,6.47053,5.90328,5.32951, -0.513959, -0.750527, -6.38895, -6.39157, -6.39418,-6.36456, -6.09357, -6.28599, -5.25369, -4.19539, -2.18625, -0.133803,2.90414, 6.171}
spfn = {33.3632, 40.2933, 46.5882, 51.9781, 55.5583, 55.5708, 55.5762,55.4604, 55.4393, 55.0045, 530116,51.1309,50.4546,48.1226,45.6012,43.402,42.066,37.5522, 32.6864, 28.1979, 28.0685,25.7067, 17.5943,13.5547, -2.97428, -3.21054,-3.36422, -5.05466, -5.1301, -6.4392,-6.76879, -6.48231, -7.20196, -7.00719, -7.53373, -6.00246, -4.41058,-2.8187, -1.16621, 2.35765, 6.04694}

第一步：

For[i = 1, i < Length@spfn, i++,
 If[spfn[[i]]*spfn[[i + 1]] < 0 && spfw[[i]]*spfw[[i + 1]] < 0,
  Print["1) exist roots: ", xnz[i] = -spmn[[i]]/spkn[[i]], ", ", 
   xwz[i] = -spmw[[i]]/spkw[[i]]] ;
  Break[]
  ]
 ]

第 2 步：

For[i = 1, i < Length@spfn, i++,
 If[(0 < spfn[[i]]) && (spfn[[i + 1]] < 0) && (0 < spfw[[i]]) && (0 < 
     spfw[[i + 1]]),
  Print["2) exist roots:", xnz[i] = -spmn[[i]]/spkn[[i]], ", ", 
   spx[[i + 1]]] ;
  Break[]
  ]
 ]

第 3 步（不起作用）：

For[i = 1, i < Length@spfn, i++,
 If[(spfn[[i]] < 0) && (0 < spfn[[i + 1]]) && (0 < spfw[[i]]) && (0 < 
     spfw[[i + 1]]),
  Print["3) exist roots:", xnz[i] = -spmn[[i]]/spkn[[i]], ", ", 
   spx[[i]]];
  Break[]
  ]
 ]

结果是：

1) exist roots: 5.58272, 5.511
2) exist roots:2.35475, 2.5

和错误：

Part::partw: Part 41 of {73.5426,66.8007,24.6942,16.4029,0.726929,0.314512,-1.23002,-1.23002,-3.90668,-10.8276,-14.2065,-13.0895,-18.656,-20.1709,-8.79676,-8.79676,<<8>>,-2.45882,-2.45882,-2.45882,-2.45882,-2.45882,-2.45882,-2.45882,-1.70357,-1.70357,-1.11799,6.1251,6.36752,6.36752,6.60995,14.0955,14.5803} does not exist. >>
Part::partw: Part 41 of {-2,-1.90577,-1.81153,-1.59327,-1.375,-1.35785,-1.3407,-1.24655,-1.22941,-1.11811,-0.934054,-0.80167,-0.75,-0.625,-0.5,-0.25,-0.0981238,0.303752,0.651876,0.94833,1,1.5,1.75,2.11731,2.5,2.5625,2.625,3.3125,3.75,4,4.00964,4.01928,4.25964,4.36731,4.5,4.75,5,5.25,5.5,5.75,6} does not exist. >>

还有一些类似的..

Answer 1

如果您从 'Code' 部分中删除以下内容，其余部分将在没有错误消息的情况下执行。

spfn[[i]] = spkn[[i]]*spx[[i]] + spmn[[i]];
spfw[[i]] = spkw[[i]]*spx[[i]] + spmw[[i]];

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