3.26.1.1 binary matrix

Gnuplot can read matrix binary files by use of the option ‘binary‘ appearing without keyword qualifications unique to general binary, i.e., ‘array‘, ‘record‘, ‘format‘, or ‘filetype‘. Other general binary keywords for translation should also apply to matrix binary. (See ‘binary general‘ for more details.)

In previous versions, ‘gnuplot‘ dynamically detected binary data files. It is now necessary to specify the keyword ‘binary‘ directly after the filename.

Single precision floats are stored in a binary file as follows:

      <N+1>  <y0>   <y1>   <y2>  ...  <yN>
       <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
       <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
        :      :      :      :   ...    :

which are converted into triplets:

      <x0> <y0> <z0,0>
      <x0> <y1> <z0,1>
      <x0> <y2> <z0,2>
       :    :     :
      <x0> <yN> <z0,N>

      <x1> <y0> <z1,0>
      <x1> <y1> <z1,1>
       :    :     :

These triplets are then converted into ‘gnuplot‘ iso-curves and then ‘gnuplot‘ proceeds in the usual manner to do the rest of the plotting.

A collection of matrix and vector manipulation routines (in C) is provided in ‘binary.c‘. The routine to write binary data is

      int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)

An example of using these routines is provided in the file ‘bf_test.c‘, which generates binary files for the demo file ‘demo/binary.dem‘.

The index keyword is not supported, since the file format allows only one surface per file. The every and using filters are supported. using operates as if the data were read in the above triplet form.

See also ‘binary general‘ and

Binary File Splot Demo.