Matlab/Octave：如何调整 .mat 文件的大小？ 为较小的文件/数据集大小降低数据分辨率

Question

I have a Matlab data set file which contains data for a grid [X , Y] . I would like to reduce the resolution of the data set file to [P , Q] , where P = X / scale and Q = Y / scale . So for example if the data set is originally 1400 x 800 and I want to scale it down by a factor of 10 I will get a new data set file with resolution 140 x 80 . How would this be done in Matlab and/or Octave?

If instead there is an easy way to convert Matlab (*.mat) files into NetCDF then I can easily take it from there, please reference if so (I haven't found anything using basic Google search). I'm aware of ncwrite but there's a catch-22 of sorts with that because I can't read the data in the first place because the .mat file is too large for my environment (I'm trying to avoid building Octave for 64-bit address space, and instead use a smaller data set while doing development).

I'm using Octave on Windows now, so I'd prefer to pull this off with Octave or another non-Matlab tool, but I may have access to a proper Matlab version soon.

Any suggestions are very appreciated, thanks for your help.

Answer 1

Easiest way I can think of is by dividing the original vectors/matrices from the .math file by the scale you want, apply a rounding function and, finally, the unique() function.

For example:

octave:1> x=1:20
x =

 Columns 1 through 16:

    1    2    3    4    5    6    7    8    9   10   11   12   13   14   15   16

 Columns 17 through 20:

   17   18   19   20

octave:2> y = round(x/4)
y =

   0   1   1   1   1   2   2   2   2   3   3   3   3   4   4   4   4   5   5   5

octave:3> unique(y)
ans =

   0   1   2   3   4   5