ENH+ACK: add support for FieldTrip MEEG data structures without "dim"…

… field. Issue reported by #Evelyn Muschter#

mvpa/cosmo_map2meeg.m

@@ -335,8 +335,6 @@ function write_eeglab_txt(fn, hdr)
     [arr, dim_labels]=cosmo_unflatten(ds,[],'set_missing_to',NaN,...
                                             'matrix_labels',{'pos'});
 
-    is_without_samples_dim=size(ds.samples,1);
-
     if cosmo_isfield(ds,'a.meeg.samples_label')
         samples_label={ds.a.meeg.samples_label};
     else
@@ -485,12 +483,18 @@ function write_eeglab_txt(fn, hdr)
 
     if cosmo_isfield(ds,'a.meeg.dim')
         ft.dim=ds.a.meeg.dim;
-    else
-        % use regular grid to determine
-        ds_vol=cosmo_vol_grid_convert(ds,'tovol');
-        ft.dim=ds_vol.a.vol.dim(:)';
     end
 
+    if cosmo_isfield(ds,'a.meeg.tri');
+        ft.tri=ds.a.meeg.tri;
+    end
+%
+%     else
+%         % use regular grid to determine
+%         ds_vol=cosmo_vol_grid_convert(ds,'tovol');
+%         ft.dim=ds_vol.a.vol.dim(:)';
+%     end
+
 
 
 function ft=build_ft(ds,unused)

mvpa/cosmo_meeg_dataset.m

@@ -276,9 +276,13 @@ function verify_trial_params(nsamples,trial_idx)
     ds.a.meeg.samples_field=samples_field;
 
     if is_ft_source_struct(ft)
-        ds=apply_ft_source_inside(ds,fdim.labels,fdim.values,...
+        if isfield(ft,'inside')
+            ds=apply_ft_source_inside(ds,fdim.labels,fdim.values,...
                                         ft.inside);
-        ds.a.meeg.dim=ft.dim;
+        end
+
+        optional_fields={'dim','tri'};
+        ds.a.meeg=copy_optional_fields(ds.a.meeg,ft,optional_fields);
     end
 
     ds.a.meeg=set_samples_label_explicitly_if_necessary(ds.a.meeg,ft);
@@ -290,6 +294,14 @@ function verify_trial_params(nsamples,trial_idx)
     ds=posthoc_slice_dataset_if_necessary(ds,opt);
 
 
+function s=copy_optional_fields(s,source,optional_fields)
+    for k=1:numel(optional_fields)
+        key=optional_fields{k};
+        if isfield(source,key)
+            s.(key)=source.(key);
+        end
+    end
+
 function a_meeg=set_samples_label_explicitly_if_necessary(a_meeg,ft)
     % deal with grand average data
     if ~cosmo_isfield(ft,'dimord')
@@ -625,7 +637,7 @@ function verify_trial_params(nsamples,trial_idx)
 
 
 function tf=is_ft_source_struct(ft)
-    tf=isstruct(ft) && isfield(ft,'pos') && isfield(ft,'inside');
+    tf=isstruct(ft) && isfield(ft,'pos');
 
 function tf=is_ft_sensor_struct(ft)
     tf=isfield(ft,'dimord') && isfield(ft,'label');

tests/test_meeg_io.m

@@ -113,6 +113,7 @@ function test_synthetic_meeg_dataset()
     assertExceptionThrown(@()cosmo_meeg_dataset(ds,'targets',[1 2]),'');
 
 
+
 function test_meeg_eeglab_txt_io()
     ds=cosmo_synthetic_dataset('type','meeg');
 
@@ -721,6 +722,53 @@ function test_dimord_label()
     end
 
 
+function test_meeg_source_dataset_pos_dim_inside_fields()
+% mapping back and forth should be fine whether or not the
+% 'pos', 'dim' and 'inside' fields are there or not
+    ds_orig=cosmo_synthetic_dataset('type','source','size','huge');
+    ft_orig=cosmo_map2meeg(ds_orig);
+
+    for has_dim=[false,true]
+        for has_tri=[false,true]
+            for has_inside=[false,true]
+                ft=ft_orig;
+
+                if has_dim
+                    ft.dim=[2 2 2];
+                end
+
+                n_pos=size(ft.pos,1);
+
+                if has_tri
+                    ft.tri=ceil(rand(5,3)*max(n_pos));
+                end
+
+                if ~has_inside
+                    ft=rmfield(ft,'inside');
+                end
+
+                func=@()cosmo_meeg_dataset(ft);
+
+                % verify fields are there
+                ds=func();
+                assertEqual(has_dim,isfield(ds.a.meeg,'dim'));
+                assertEqual(has_tri,isfield(ds.a.meeg,'tri'));
+
+                % map back
+                ft_back=cosmo_map2meeg(ds);
+
+                % cosmo_map2meeg always returns an inside field, so for
+                % now we remove it if it is present here
+                if ~has_inside
+                    ft_back=rmfield(ft_back,'inside');
+                end
+
+                % ensure expected fields are preserved
+                assertEqual(ft,ft_back);
+            end
+        end
+    end
+
 
 function x=randint()
     x=ceil(rand()*10+5);