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performance tuning - Fast way to export large amount of data in "Table" format


I have about a million 3D points, say


data = Table[{1. x, 1. y, 0.}, {x, 1000}, {y, 10^3}]~Flatten~1;


I want to visualize them, but Graphics3D@Point@data or ListPointPlot3D@data are too slow.


MeshLab or CloudCompare can do it, but I need to export it in some way to get it there. It can read ".txt" files with the "Table" format that Mathematica produces, but that takes a very long time to write:


AbsoluteTiming@Export["test 1mio points.txt", data, "Table"]



{23.9979, "test 1mio points.txt"}


CSV file writing is not much faster. It doesn't look like there is a general bottleneck in converting numbers to text format, as '.m' is written quite quickly:


AbsoluteTiming@Export["test 1mio points.m", data]


{1.92666, "test 1mio points.m"}


but MeshLab cannot handle it.


Any alternatives? Is there a way I can convert a list of points to a GraphicsComplex or Mesh or so and then export that in some format (that might be faster).



Answer



I started working on a package and LinkedLibrary achieving significant speedups with this job:


data = Table[{1. x, 1. y, 0.}, {x, 1000}, {y, 10^3}]~Flatten~1;
<< ExportTable`

AbsoluteTiming@ExportTable["test 1mio points.txt", data]

{0.0381513, Null}


You can find it here: https://github.com/Masterxilo/ExportTable


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