这是一种基于 Szabolcs 帖子的方法,速度大约快一个数量级。
data = RandomReal[5, {500000, 3}];
(*500k values*)
zvalues = data[[All, 3]];
epsilon = 1*^-10;(*prevent 101 index*)
(*rescale and round (x,y) coordinates to index pairs in the 1..100 range*)
indexes = 1 + Floor[(1 - epsilon) 100 Rescale[data[[All, {1, 2}]]]];
res2 = Module[{gb = GatherBy[Transpose[{indexes, zvalues}], First]},
SparseArray[
gb[[All, 1, 1]] ->
Total[gb[[All, All, 2]], {2}]]]; // AbsoluteTiming
给出大约 {2.012217, Null}
AbsoluteTiming[
System`SetSystemOptions[
"SparseArrayOptions" -> {"TreatRepeatedEntries" -> 1}];
res3 = SparseArray[indexes -> zvalues];
System`SetSystemOptions[
"SparseArrayOptions" -> {"TreatRepeatedEntries" -> 0}];
]
给出大约 {0.195228, Null}
res3 == res2
True
"TreatRepeatedEntries" -> 1 添加重复位置。