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MNEProjOp

Namespace: MNELIB  ·  Library: MNE Library

#include <mne/mne_proj_op.h>

class MNELIB::MNEProjOp

Projection operator managing a set of linear projection items and the final compiled projector matrix.

MNEProjOp aggregates zero or more MNEProjItem entries, each holding a named matrix of projection vectors. When the operator is compiled (make_projector), the individual items are orthogonalised into a single dense projector stored in proj_data.

Public Methods​

MNEProjOp()​

Default constructor.

Creates an empty operator with no projection items.

~MNEProjOp()​

Destructor.

free_proj()​

Release the compiled projector data.

Clears proj_data, names, nch, and nvec without touching the underlying projection items.

combine(from)​

Append all projection items from another operator.

Each item's active_file flag is preserved.

Parameters:

  • from : *MNEProjOp ** Source operator whose items are copied.

Returns:

  • *MNEProjOp ** — Pointer to this operator.

add_item_active(vecs, kind, desc, is_active)​

Add a projection item with an explicit active/inactive state.

The projection kind (MEG/EEG) is auto-detected from channel names.

Parameters:

  • vecs : *const MNENamedMatrix ** Named matrix holding the projection vectors.

  • kind : int Projection kind constant.

  • desc : const QString & Human-readable description of the projection.

  • is_active : bool Whether the item is active on load.

add_item(vecs, kind, desc)​

Add a projection item that is active by default.

Convenience wrapper around add_item_active() with is_active = TRUE.

Parameters:

  • vecs : *const MNENamedMatrix ** Named matrix holding the projection vectors.

  • kind : int Projection kind constant.

  • desc : const QString & Human-readable description of the projection.

dup()​

Create a deep copy of this projection operator.

Copies all items, their vectors, descriptions, and active states.

Returns:

  • std::unique_ptr< MNEProjOp > — A newly allocated copy. Caller takes ownership.

affect(list, nlist)​

Count how many active projection vectors affect a given list of channel names.

Parameters:

  • list : const QStringList & List of channel names to test.

  • nlist : int Number of channel names.

Returns:

  • int — Number of projection vectors that affect at least one channel in the list (0 if none).

affect_chs(chs, nch)​

Count how many active projection vectors affect the given channels.

Convenience wrapper that extracts channel names and delegates to affect().

Parameters:

  • chs : const QList< FiffChInfo > & Channel information list.

  • nch : int Number of channels.

Returns:

  • int — Number of affecting projection vectors (0 if none or nch == 0).

project_vector(vec, do_complement)​

Apply the compiled projection operator to a data vector in-place.

If do_complement is true, the projected components are subtracted from vec (signal cleaning). Otherwise, vec is replaced by the projection itself.

Parameters:

  • vec : Eigen::Ref< Eigen::VectorXf > Data vector of length nch.

  • do_complement : bool If true, compute the complement (I - P) * vec.

Returns:

  • int — OK on success, FAIL on dimension mismatch.

report_data(out, tag, list_data, exclude)​

Write a formatted summary of all projection items to a text stream, optionally including the full projection vector data while zeroing out excluded channels.

Parameters:

  • out : QTextStream & The text stream to write to.

  • tag : const QString & Prefix string printed before each line.

  • list_data : bool If true, print full vector data.

  • exclude : const QStringList & Channel names to exclude from the display.

report(out, tag)​

Write a one-line-per-item summary of all projection items to a text stream (no vector data).

Convenience wrapper around report_data().

Parameters:

  • out : QTextStream & The text stream to write to.

  • tag : const QString & Prefix string printed before each line.

assign_channels(list, nlist)​

Assign a channel name list to this projection operator, invalidating any previously compiled projector.

Parameters:

  • list : const QStringList & Channel name list.

  • nlist : int Number of channels.

Returns:

  • int — OK on success.

make_proj_bad(bad)​

Compile the projection operator via SVD, excluding bad channels.

Active projection items are picked, expanded to the assigned channel list, bad channels are zeroed, and SVD is performed to produce an orthogonal projector matrix stored in proj_data.

Parameters:

  • bad : const QStringList & List of bad channel names.

Returns:

  • int — OK on success, FAIL on error.

make_proj()​

Compile the projection operator via SVD (no bad channels).

Convenience wrapper around make_proj_bad().

Returns:

  • int — OK on success, FAIL on error.

project_dvector(vec, do_complement)​

Apply the compiled projection operator to a double-precision data vector.

Parameters:

  • vec : Eigen::Ref< Eigen::VectorXd > Data vector.

  • do_complement : bool If true, compute (I - P) * vec.

Returns:

  • int — OK on success, FAIL on dimension mismatch.

apply_cov(c)​

Apply this projection operator to a covariance matrix from both sides: C' = (I - P) C (I - P)^T (or P C P^T if do_complement is false).

Parameters:

Returns:

  • int — OK on success, FAIL on error.

Static Methods​

create_average_eeg_ref(chs, nch)​

Create an average EEG reference projector.

Builds a uniform-weight vector ( 1/{N{{EEG}}}1/\sqrt\{N_\{\text\{EEG\}\}\}) across all EEG channels.

Parameters:

  • chs : const QList< FiffChInfo > & Channel information list.

  • nch : int Number of channels.

Returns:

  • std::unique_ptr< MNEProjOp > — A new projection operator, or NULL if no EEG channels are found. Caller takes ownership.

read_from_node(stream, start)​

Read all linear projection items from a FIFF tree node.

Parameters:

Returns:

  • std::unique_ptr< MNEProjOp > — A populated projection operator (possibly with zero items), or NULL on error. Caller takes ownership.

read(name)​

Read a projection operator from a FIFF file by path.

Convenience wrapper that opens the file and delegates to read_from_node().

Parameters:

  • name : const QString & Path to the FIFF file.

Returns:

  • std::unique_ptr< MNEProjOp > — The loaded projection operator, or NULL on error. Caller takes ownership.

makeProjection(projnames, chs, nch, result)​

Load and combine SSP projection operators from files for the selected channels.

Reads projection items from each file in projnames, and if EEG channels are present adds an average EEG reference projector when none is found. Returns nullptr if the resulting projector does not affect any of the given channels.

Refactored: make_projection (dipole_fit_setup.c)

Parameters:

  • projnames : const QList< QString > & List of FIFF file paths containing projection data.

  • chs : const QList< FiffChInfo > & Channel information list.

  • nch : int Number of channels.

  • result : std::unique_ptr< MNEProjOp > & The combined projection operator (nullptr when no projection is needed).

Returns:

  • bool — true on success, false on read error.

Authors of this file​