problem finding electrodes reference on write

[bendichter]

date = datetime(2018, 3, 1, 12, 0, 0);
nwb = nwbfile( 'source', 'acquired on rig2', ...
    'session_description', 'a test NWB File', ...
    'identifier', 'mouse004_day4', ...
    'session_start_time', datestr(date, 'yyyy-mm-ddTHH:MM:SS'), ...
    'file_create_date', datestr(now, 'yyyy-mm-ddTHH:MM:SS'));

device_labels = {'a','a','a','a','a','b','b','b','b','b'};
udevice_labels = unique(device_labels, 'stable');

variables = {'id', 'x', 'y', 'z', 'imp', 'location', 'filtering', ...
    'description', 'group', 'group_name'};
for i_device = 1:length(udevice_labels)
    device_label = udevice_labels{i_device};

    nwb.general_devices.set(device_label,...
        types.core.Device('source', 'lab notebook'));

    nwb.general_extracellular_ephys.set(device_label,...
        types.core.ElectrodeGroup('source', 'my source', ...
        'description', 'a test ElectrodeGroup', ...
        'location', 'unknown', ...
        'device', types.untyped.SoftLink(['/general/devices/' device_label])));

    ov = types.untyped.ObjectView(['/general/extracellular_ephys/' device_label]);

    elec_nums = find(strcmp(device_labels, device_label));
    for i_elec = 1:length(elec_nums)
        elec_num = elec_nums(i_elec);
        if i_device == 1 && i_elec == 1
            tbl = table(int64(1), NaN, NaN, NaN, NaN, {'CA1'}, {'filtering'}, ...
                {'electrode label'}, ov, {'electrode_group'},...
                'VariableNames', variables);
        else
            tbl = [tbl; {int64(elec_num), NaN, NaN, NaN, NaN,...
                'CA1', 'filtering', 'another label', ov, 'electrode_group'}];
        end
    end        
end

et = types.core.ElectrodeTable('data', tbl);
nwb.general_extracellular_ephys.set('electrodes', et);

rv = types.untyped.RegionView('/general/extracellular_ephys/electrodes',...
    {[1 height(tbl)]});

electrode_table_region = types.core.ElectrodeTableRegion('data', rv);

electrical_series = types.core.ElectricalSeries(...
    'source', 'my source', ...
    'starting_time', 0.0, ... % seconds
    'starting_time_rate', 200., ... % Hz
    'data',randn(1000, 10),...
    'electrodes', electrode_table_region,...
    'data_unit','V');

nwb.acquisition.set('ECoG', electrical_series);

nwbExport(nwb, 'ecephys_tutorial.nwb')

Error using nwbfile/export (line 46)
Could not resolve paths for the following reference(s):
    /acquisition/ECoG/electrodes

Error in nwbExport (line 34)
    export(nwb(i), fn);

[lawrence-mbf]

The quick fix is to make region references vertical array of bounds a la:

rv = types.untyped.RegionView('/general/extracellular_ephys/electrodes',...
    {[1; height(tbl)]});

Fix is forthcoming.