将 Matlab 多维元胞数组转换为 Javascript 数组的最佳方法是什么？

Question

I have a very large 4D Matlab matrix (31x31x86x127) that I wish to convert into a Javascript 4D array. What is the best way to do this?

Currently my tentative approach will be to either:

1) Write the Matlab matrix into a binary file, and then read that in and build the Javascript.

2) Use JSONlab ( http://www.mathworks.com/matlabcentral/fileexchange/33381-jsonlab--a-toolbox-to-encode-decode-json-files-in-matlab-octave ) to convert the Matlab matrix into a JSON string and then write a custom decoder to turn that JSON string into a Javascript Array. Issue is that the JSON text file is 1.98GB...

3) This may be the best way.

fileID = fopen('test.bin', 'w'); fwrite(fileID,value,'double');

Test.bin is then around 82MB, which is actually what I expect. 31*31*86*127*8bits/double = 82ish MB! However, how do I then read (in the browser) this binary file to a 4d Javascript array? Thanks! Thoughts?

Thanks for your help!

Answer 1

save is not the right function to write a text file. Use savejson or saveubjson and pass the filename to the function. Do not use the return argument of these functions. Doing so I get a ubjson with less than 100MB and a json with less than 150MB.

My original answer, based on insufficient knowledge about the used code:

Instead of writing your own binary format, use one of the already available binary formats. Try writing it to universal binary json, jsonlab does support it. you should end up with a reasonable sized data without losing the advantages of a standardized file exchange format.

Answer 2

I think the best way is to

1. Write the matrix out as a string or text file (binary file is not necessary). You will need n-1 delimiters, where n=4 is the number of dimensions for your case. See this Saturn Fiddle as an example for a 2D matrix. Code below
2. Read the text file into a JavaScript string. How you do this really depends on if you're using JavaScript on the server or web browser.
3. Parse the string into a JavaScript array. You will have to use the split function on the delimiters from (1) and then enter them into an array like this example .

Code part (1):

% Welcome to SaturnAPI!
% Start collaborating with MATLAB-Octave fiddles and accomplish more.
% Start your script below these comments.
A = [ 1 2 3 ; 4 5 6 ; 7 8 9 ]
for ii=1:size(A)(1)
    for jj=1:size(A)(2)
        printf(" %d ", A(ii,jj));
  end
  printf(";");
end

Code part (3):

function make(dim, lvl, arr) {
  if (lvl === 1) return [];
  if (!lvl) lvl = dim;
  if (!arr) arr = [];
  for (var i = 0, l = dim; i < l; i += 1) {
    arr[i] = make(dim, lvl - 1, arr[i]);
  }
  return arr;
}

var myMultiArray = make(4);