Error using calculate_NRpars, fatal error: run without parallel processing for more information

[mansur007]

I am following the demo1 tutorial but got this error...

>> base_dir = 'C:\nr_data\';
>> calculate_NRpars(ccriq_dataset, base_dir, 'stimuli', @nrff_blur);
Progress blur NR features, dataset ccriq, directory C:\nr_data\group_blur\:
0 of 784 media files already calculated

................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

Warning: File: calculate_one_media.m Line: 253 Column: 26
The temporary variable 'y' will be cleared at the beginning of each iteration of the parfor-loop. If 'y' is used before it is set, a runtime error will occur. For more information, see Parallel for
Loops in MATLAB, "Uninitialized Temporaries". 
> In parallel_function (line 494)
In calculate_NRpars (line 341) 
Warning: File: calculate_one_media.m Line: 255 Column: 28
The temporary variable 'cb' will be cleared at the beginning of each iteration of the parfor-loop. If 'cb' is used before it is set, a runtime error will occur. For more information, see Parallel for
Loops in MATLAB, "Uninitialized Temporaries". 
> In parallel_function (line 494)
In calculate_NRpars (line 341) 
Warning: File: calculate_one_media.m Line: 255 Column: 31
The temporary variable 'cr' will be cleared at the beginning of each iteration of the parfor-loop. If 'cr' is used before it is set, a runtime error will occur. For more information, see Parallel for
Loops in MATLAB, "Uninitialized Temporaries". 
> In parallel_function (line 494)
In calculate_NRpars (line 341) 
Error using calculate_NRpars
fatal error: run without parallel processing for more information
 

I tried changing parfor loop in calculate_NRpars.m line 341 to for loop but it didn't help.
Any ideas?
I am using Matlab R2023a. Do you recommend using another version?

Thank you

[mpinson-NTIA]

Sorry for the delay. I didn't know about this mechanism for Q&A.

This error message can be ignored. Variable 'y' is a temporary variable that is overwritten each time through the loop. This error message is supposed to be suppressed.

This loop is loading video into three variables, one for each image plane: y, cb, and cr. Each time through the loop overwrites these variables, to enable processing of more video.

To see this, go to function calculate_one_media.m (called by calculate_NRpars.m). There are a few options, but each of them loads an image or some frames of video into these variables, using code that looks like this:

        if feature_function('luma_only')
            [y] = read_media('all', nr_dataset, media_num);
        else
            [y,cb,cr] = read_media('all', nr_dataset, media_num);
        end

Then calculate_one_media.m calls the NRFF to calculate your features.