MLLoadWave does not load string matrix (matlab 2018a, igor7)


I need to load  a bigger matlab file into igor.

One of the objects in the *.mat file is "par_out" a 26x2 string matrix.

Using (with "instring" being the filename):

MLLoadWave /o /M=2/Y=2/S=3 instring

creates the following error:

Skipping par_out, unsupported data type (unknown type of data)

while I found a work around by using xlswrite in malab and XLLoadWave in Igor to get the data set in, its quite  a hassle.


Any Ideas would be appreciated.







Thank you.

 I just saved the problematic matrix and  two content vectors.

As a work around ( so it is no longer urgent) I save now only the numbers, as both text parts do not load.


Is the first string starting with a number a problem?




Igor is calling the Matlab mxGetClassID routine. That routine returns results of type mxClassID.

For the matrix where you get "unsupported data type", mxGetClassID is returning mxUNKNOWN_CLASS. This means that the version of the Matlab DLL that you are using and that I am using does not support the class of data in that matrix.

For a normal matrix of strings, it should return mxCHAR_CLASS.

This make me think that there is something funny about how you are writing that matrix, but I don't have any idea of what it might be. Try inspecting it in Matlab and comparing it to a string matrix that Igor can load.


Thanks a lot,

I adopted the Matlab script to write the needed information in a igor readable form.

Strangely I was pointing Igor to the same matlab directory I used in generating the mat file - Matlab's assigning data types caused me problems before, even within Matlab.

I could skip Matlab altogether if Igor could use Bioformats ( in a similar form as Matlab can (…).

Cheers and happy holiday



I don't know much about Bioformats, but it looks like it's a Java library and I don't know that it's feasible for Igor or an XOP to use a Java library. As far as I know we don't have any expertise in Java, so even if it's possible I'm sure there would be a steep learning curve. Also, most of the formats are available only using the GPL license (which Igor and XOPs can't use) or a commercial license. I don't see pricing information for the commercial license, which probably means it's expensive :)

Maybe it's possible to call the command line tools version (…) from Igor using ExecuteScriptText?

If you can export as HDF5, I would recommend that.

If you are not familiar with Igor's HDF5 support, execute:

DisplayHelpTopic "HDF5XOP"