Mathematica大表周期内插
我在Mathematica中有一个很大的表（（dimcub-1）^ 3个元素）来自逆FFT。我需要在此表上使用定期插值。由于周期性插值要求第一个元素和最后一个元素相等，因此我手动创建了一个新的dim_3元素表，并将其用于我的插值。它可以工作，但是很丑/很慢，由于我多余的中间表，我很快就遇到了内存障碍。谁能告诉我如何通过附加元素将旧表转换为周期表，或者使用我的非周期表创建周期插值函数？这是我当前的代码：
mr 1
mr1 = Table[ 0. , {i, 1, dimcub}, {j, 1, dimcub}, {k, 1, dimcub}];
Do[Do[ Do[
mr1[[m, n, k]] = oldtable[[m, n, k]] ; , {m, 1,
dimcub - 1}]; , {n, 1, dimcub - 1}]; , {k, 1, dimcub - 1}];
Do[Do[ mr1[[m, n, dimcub]] = mr1[[m, n, 1]];
mr1[[m, dimcub, n]] = mr1[[m, 1, n]];
mr1[[dimcub, m, n]] = mr1[[1, m, n]]; , {m, 1, dimcub - 1}];
mr1[[n, dimcub, dimcub]] = mr1[[n, 1, 1]];
mr1[[dimcub, n, dimcub]] = mr1[[1, n, 1]];
mr1[[dimcub, dimcub, n]] = mr1[[1, 1, n]]; , {n, 1, dimcub - 1}];
mr1[[dimcub, dimcub, dimcub]] = mr1[[1, 1, 1]];
Remove[oldtable];
myinterpolatingfunction =
ListInterpolation[mr1, {{1, dimcub}, {1, dimcub}, {1, dimcub}},
InterpolationOrder -> 1,
PeriodicInterpolation -> True];
Remove[mr1];
myinterpolatingfunction
没有找到相关结果
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4 个回复
碧肮械淌设
In[65]:= len = 4; oldtable = Partition[Partition[Range[len^3], len], len] Out[65]= {{{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}}, {{17, 18, 19, 20}, {21, 22, 23, 24}, {25, 26, 27, 28}, {29, 30, 31, 32}}, {{33, 34, 35, 36}, {37, 38, 39, 40}, {41, 42, 43, 44}, {45, 46, 47, 48}}, {{49, 50, 51, 52}, {53, 54, 55, 56}, {57, 58, 59, 60}, {61, 62, 63, 64}}} In[66]:= oldtable[[All, All, -1]] = oldtable[[All, All, 1]]; oldtable[[All, -1, All]] = oldtable[[All, 1, All]]; oldtable[[-1, All, All]] = oldtable[[1, All, All]]; oldtable[[All, -1, -1]] == oldtable[[All, 1, 1]] oldtable[[-1, All, -1]] == oldtable[[1, All, 1]] oldtable[[-1, -1, All]] == oldtable[[1, 1, All]] oldtable[[-1, -1, -1]] == oldtable[[1, 1, 1]] Out[69]= True Out[70]= True Out[71]= True Out[72]= True芦歉竭皑
这些分配取代了嵌套循环，并且速度更快，而且您不需要内存来存储副本。这基于Part命令的扩展矢量化功能（数组和通用表达式索引），尤其是矢量化分配。将数字数组设置为打包数组的形式也很重要，这是常见的情况。系漏
a = {0, 1}~Tuples~3~SortBy~Tr // Rest; MapThread[ (oldtable[[Sequence @@ #]] = oldtable[[Sequence @@ #2]]) &, {-a, a} /. 0 -> All ];瞥同忙接
oldtable= PadRight[oldtable, {dimcub, dimcub, dimcub}]; oldtable[[All, All, dimcub]] = oldtable[[All, All, 1]]; oldtable[[All, dimcub, All]] = oldtable[[All, 1, All]]; oldtable[[dimcub, All, All]] = oldtable[[1, All, All]]; oldtable[[All, dimcub, dimcub]] = oldtable[[All, 1, 1]]; oldtable[[dimcub, All, dimcub]] = oldtable[[1, All, 1]]; oldtable[[dimcub, dimcub, All]] = oldtable[[1, 1, All]]; oldtable[[dimcub, dimcub, dimcub]] = oldtable[[1, 1, 1]];