Undefined function or variable 'rootFolder'.

When I am training to implement this function

     imageDatastore

I receive

    Undefined function or variable 'rootFolder'.

I have this version and those toolbox in my machine

ver
----------------------------------------------------------------------------------------------------

MATLAB Version: (R2015b)

Operating System: Linux 
----------------------------------------------------------------------------------------------------

MATLAB                                                Version 8.6         (R2015b)
Image Processing Toolbox                              Version 9.3         (R2015b)
Neural Network Toolbox                                Version 8.4         (R2015b)
Optimization Toolbox                                  Version 7.3         (R2015b)
Parallel Computing Toolbox                            Version 6.7         (R2015b)
Statistics and Machine Learning Toolbox               Version 10.1        (R2015b)

Any help please

By the way I checked preference and make set the path to default but same problem,

[Walter Roberson]

Please show your code and the complete error message

[Salem]

I am trying to implement convolution neural network in this link http://uk.mathworks.com/help/nnet/convolutional-neural-networks.html and I recieved this error

        imageDatastore undefine
        Undefined function or variable 'rootFolder'.

Answer 1

[Walter Roberson]

The code has the line

rootFolder = fullfile(outputFolder, '101_ObjectCategories');

above the point where it uses rootFolder, so you must have missed some lines in your implementation.

[Salem]

Mnay thanks for replying, I have tried many times but same error this is the code which I copied it.

     % Download the compressed data set from the following location
     url = 'http://www.vision.caltech.edu/Image_Datasets/Caltech101  /101_ObjectCategories.tar.gz';
     % Store the output in a temporary folder
      outputFolder = fullfile(tempdir, 'caltech101'); % define  output folder
      >> 
      >> 
      >> if ~exist(outputFolder, 'dir') % download only once
      disp('Downloading 126MB Caltech101 data set...');
      untar(url, outputFolder);
      end
      >> 
      >> 
      >> rootFolder = fullfile(outputFolder, '101_ObjectCategories');
      categories = {'airplanes', 'ferry', 'laptop'};
      >> imds = imageDatastore(fullfile(rootFolder, categories),   'LabelSource', 'foldernames');
     Undefined function or variable 'imageDatastore'.

     >>

[Walter Roberson]

The function imageDatastore appears to be new as of R2016a, which is confusing because ImageDatastore objects are documented as existing from R2015b, but were at that time only accessible by using datastore()

[Salem]

OK, what I can do as I have R2015b and I bought it only in this January.

[Walter Roberson]

If you bought R2015b within the last calendar year, then if you bought anything other than the cheapest version of the Student Version license, then included in that should have been one year of Software Maintenance Service (SMS). That would entitle you to upgrade to all MATLAB versions released within one year. As R2016a was released well within that year, you should be able to go to https://www.mathworks.com/downloads/select_release?mode=gwylf and download R2016a.

Note: the "unbundled" Student Version license, the very least expensive student license, might possibly not include this service.