External Interfaces/API

Creating a MAT-File in Fortran

This example creates a MAT-file, matdemo.mat.

C $ Revision: 1.6 $
C
C     matdemo1.f
C
C     This is a simple program that illustrates how to call the
C     MATLAB MAT-file functions from a Fortran program.  This
C     demonstration focuses on writing MAT-files.
C
C     Copyright (c) 1984-2000 The MathWorks, Inc.
C 
C

C
C     matdemo1 - Create a new MAT-file from scratch.
C
      program matdemo1
C--------------------------------------------------------------
C     (integer) Replace integer by integer*8 on the DEC Alpha  
C     platform.
C
      integer matOpen, mxCreateFull, mxCreateString
      integer matGetMatrix, mxGetPr
      integer mp, pa1, pa2, pa3
C--------------------------------------------------------------
C
C     Other variable declarations here
C     
      integer status, matClose
      double precision dat(9)
      data dat / 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0 /
C
C     Open MAT-file for writing.
C
      write(6,*) 'Creating MAT-file matdemo.mat ...'
      mp = matOpen('matdemo.mat', 'w')
      if (mp .eq. 0) then

  write(6,*) 'Can''t open ''matdemo.mat'' for writing.'
  write(6,*) '(Do you have write permission in this directory?)'

         stop
      end if
C
C     Create variables.
C
      pa1 = mxCreateFull(3,3,0)
      call mxSetName(pa1, 'Numeric')
C
      pa2 = mxCreateString('MATLAB: The language of computing')
      call mxSetName(pa2, 'String')
C
      pa3 = mxCreateString('MATLAB: The language of computing')
      call mxSetName(pa3, 'String2')
C
      call matPutMatrix(mp, pa1)
      call matPutMatrix(mp, pa2)
      call matPutMatrix(mp, pa3)
C
C     Whoops! Forgot to copy the data into the first matrix -- 
C     it's now blank. (Well, ok, this was deliberate.)  This 
C     demonstrates that matPutMatrix will overwrite existing 
C     matrices.
C
      call mxCopyReal8ToPtr(dat, mxGetPr(pa1), 9)
      call matPutMatrix(mp, pa1)
C
C     Now, we'll delete String2 from the MAT-file.
C
      call matDeleteMatrix(mp, 'String2')
C
C     Finally, read back in MAT-file to make sure we know what we 
C     put in it.
C
      status = matClose(mp)
      if (status .ne. 0) then
         write(6,*) 'Error closing MAT-file'
         stop
      end if
C
      mp = matOpen('matdemo.mat', 'r')
      if (status .ne. 0) then
         write(6,*) 'Can''t open ''matdemo.mat'' for reading.'
         stop
      end if
C
      pa1 = matGetMatrix(mp, 'Numeric')
      if (mxIsNumeric(pa1) .eq. 0) then
        write(6,*) 'Invalid non-numeric matrix written to MAT-file'
       stop
      end if
C
      pa2 = matGetMatrix(mp, 'String')
      if (mxIsString(pa2) .eq. 0) then
        write(6,*) 'Invalid non-numeric matrix written to MAT-file'
        stop
      end if
C
      pa3 = matGetMatrix(mp, 'String2')
      if (pa3 .ne. 0) then
         write(6,*) 'String2 not deleted from MAT-file'
         stop
      end if
C
      status = matClose(mp)
      if (status .ne. 0) then
         write(6,*) 'Error closing MAT-file'
         stop
      end if
C
      write(6,*) 'Done creating MAT-file'
      stop
      end

Once you have compiled and linked your MAT-file program, you can run the stand-alone application you have just produced. This program creates a MAT-file, matdemo.mat, that can be loaded into MATLAB. To run the application, depending on your platform, either double-click on its icon or enter matdemo1 at the system prompt.

matdemo1
Creating MAT-file matdemo.mat ...
Done creating MAT-file

To verify that the MAT-file has been created, at the MATLAB prompt enter

 whos -file matdemo.mat
 Name          Size         Bytes  Class
 
 Numeric       3x3             72  double array
 String        1x33            66  char array
 
Grand total is 42 elements using 138 bytes

Note    For an example of a Windows stand-alone program (not MAT-file specific), see engwindemo.c in the <matlab>\extern\examples\eng_mat directory.

Reading a MAT-File in C

Reading a MAT-File in Fortran