BIDS stats model handling

See the BIDS stats model website for more information.

class +bids.Model(varargin)

Class to deal with BIDS stats models

See the BIDS stats model website for more information.

USAGE:

bm = bids.Model('init', true, ...
                 'file', path_to_bids_stats_model_file, ...
                 'tolerant', true,
                 'verbose', false);

Parameters:

• init (logical) – if true this will initialize an empty model. Defaults to false.

• file (path) – fullpath the JSON file containing the BIDS stats model

• tolerant (logical) – turns errors into warning

• verbose (logical) – silences warnings

EXAMPLE:

% initialize and write an empty model
bm = bids.Model('init', true);
filename = fullfile(pwd, 'model-foo_smdl.json');
bm.write(filename);

EXAMPLE:

% load a stats model from a file
model_file = fullfile(get_test_data_dir(), ...
                      '..', ...
                      'data', ...
                      'model', ['model-narps_smdl.json']);

bm = bids.Model('file', model_file, 'verbose', false);

content = "''"

“raw” content of a loaded JSON

Name = "'REQUIRED'"

Name of the model

Description = "'RECOMMENDED'"

Description of the model

BIDSModelVersion = "'1.0.0'"

Version of the model

Input = "'REQUIRED'"

Input of the model

Nodes = "{'REQUIRED'}"

Nodes of the model

Edges = '{}'

Edges of the model

tolerant = 'true'

if true turns error into warning

verbose = 'true'

hides warning if false

get_nodes(varargin)

Get a specific node from the model given its Level and / or Name.

USAGE:

[value, idx] = bm.get_nodes('Level', '', 'Name', '')

Parameters:

• Level – Must be one of Run, Session, Subject, Dataset. Default to ''

• Name – Default to ''

Returns: value - Node(s) as struct if there is only one or a cell if more

idx - Node index

EXAMPLE:

bm = bids.Model('file', model_file('narps'), 'verbose', false);

% Get all nodes
bm.get_nodes()

% Get run level node
bm.get_nodes('Level', 'Run')

% Get the "Negative" node
bm.get_nodes('Name', 'negative')

get_edge(field, value)

USAGE:

edge = bm.get_edges(field, value)

field can be any of {‘Source’, ‘Destination’}

get_edges_from_nodes()

Generates all the default edges from the list of nodes in the model.

USAGE:

bm = bm.get_edges_from_nodes();
edges = bm.Edges();

validate()

Very light validation of fields that were not checked on loading. Automatically run on loaoding of a dataset.

USAGE:

bm.validate()

validate_edges()

USAGE:

bm.validate_edges()

get_transformations(varargin)

USAGE:

transformations = bm.get_transformations('Name', 'node_name')

Parameters:

Name (char) – name of the node whose transformations we want

get_dummy_contrasts(varargin)

USAGE:

dummy_contrasts = bm.get_dummy_contrasts('Name', 'node_name')

Parameters:

Name (char) – name of the node whose dummy contrasts we want

get_contrasts(varargin)

USAGE:

contrasts = bm.get_contrasts('Name', 'node_name')

Parameters:

Name (char) – name of the node whose contrasts we want

get_model(varargin)

USAGE:

model = bm.get_model('Name', 'node_name')

Parameters:

Name (char) – name of the node whose model we want

get_design_matrix(varargin)

USAGE:

matrix = bm.get_design_matrix('Name', 'node_name')

Parameters:

Name (char) – name of the node whose model matrix we want

default(varargin)

Generates a default BIDS stats model for a given data set

USAGE:

bm = bm.default(BIDS, tasks)

Parameters:

• BIDS (path or structure) – fullpath to a BIDS dataset or output structure from bids.layout

• tasks (char or cellstr) – tasks to include in the model

EXAMPLE:

pth_bids_example = get_test_data_dir();
BIDS = bids.layout(fullfile(pth_bids_example, 'ds003'));
bm = bids.Model();
bm = bm.default(BIDS, 'rhymejudgement');
filename = fullfile(pwd, 'model-rhymejudgement_smdl.json');
bm.write(filename);

update()

Update content for writing

USAGE:

bm = bm.update()

write(filename)

USAGE:

bm.write(filename)

static empty_node(level)

USAGE:

node = Model.empty_node('run')

static empty_transformations()

USAGE:

transformations = Model.empty_transformations()

static empty_model()

USAGE:

model = Model.empty_model()