How to open binary file where each number has different precision?

I have to open a binary file and I have to order it in a matrix of 3 columns where in the 1st column there are integers and in the 2nd and the 3rd long double. With freed I got an [m,3] matrix of integers.

[Jan]

Please post the complete command: How do you call fread?

Answer 1

[Sanjana Ramakrishnan]

The answer posted in the below MATLAB Answers link would address your requirement:

https://www.mathworks.com/matlabcentral/answers/100727-how-can-i-read-a-binary-file-containing-records-with-multiple-formats-in-matlab-7-9-r2009b

Answer 2

[Image Analyst]

Just call fread() multiple times, once for each data type. Like call it once for an integer then once for a 2-element long array of doubles, then on to the next row and you call it once for an integer then again for a pair of doubles and so on until the whole array is read. For example, see this snippet:

% Go to the beginning of the file.
  % Shouldn't be necessary, but can't hurt.
  fseek(fileHandleID, 0, 'bof');

  % Read the total number of voxels in the image.
  % Read bytes 1-4.
  stHeader.TotalVoxels = fread(fileHandleID, 1, '*int32');
  % Note: this may be unreliable, and can be zero!
  % Better to take the x, y, and z sizes and multiply them together.

  % The next 4 bytes are the number of dimensions - 2 or 3.
  % Read bytes 5-8.
  stHeader.NumberOfDimensions = fread(fileHandleID, 1, 'int32');

  % Read in the dimensions for the different directions.
  % They'll be in bytes 9-20.
  stHeader.x_size = fread(fileHandleID, 1, '*int32');
  stHeader.y_size = fread(fileHandleID, 1, '*int32');
  stHeader.z_size = fread(fileHandleID, 1, '*int32');
  stHeader.TotalVoxels = stHeader.x_size * stHeader.y_size * stHeader.z_size;

  % Read in the position of the center of the first pixel.
  % They'll be in bytes 21-32.
  stHeader.XStart = fread(fileHandleID, 1, '*float');
  stHeader.YStart = fread(fileHandleID, 1, '*float');
  stHeader.ZStart = fread(fileHandleID, 1, '*float');