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InvVolumeSourceEstimate

Namespace: INVLIB  ·  Library: Inverse Library

Python equivalent

mne.VolumeSourceEstimate in MNE-Python.

#include <inv/inv_volume_source_estimate.h>

class INVLIB::InvVolumeSourceEstimate

Volume source estimate: scalar values at voxel locations.

Extends InvSourceEstimate with grid shape information to allow reshaping the flat data into a 3D volume.

src/examples/ex_inv_api/main.cpp
// A volume estimate keeps the grid shape, so a time slice can be written back into the full grid.
InvVolumeSourceEstimate volumeStc(stc.data.topRows(4), VectorXi::LinSpaced(4, 0, 6), stc.tmin, stc.tstep);
volumeStc.setShape({2, 2, 2}); // 8 voxels, 4 of them sources
const VectorXd grid = volumeStc.toVolume(200);

Inheritance​

Public Methods​

InvVolumeSourceEstimate()​

InvVolumeSourceEstimate(p_sol, p_vertices, p_tmin, p_tstep)​

Construct from data and vertices.

Parameters:

  • p_sol : const Eigen::MatrixXd & Data (n_voxels x n_times).

  • p_vertices : const Eigen::VectorXi & Voxel indices.

  • p_tmin : float Start time.

  • p_tstep : float Time step.

setShape(shape)​

Set the 3D grid shape (nx, ny, nz) for volume reshaping.

Parameters:

  • shape : const QVector< int > & Grid dimensions {nx, ny, nz}.

shape()​

Get the 3D grid shape.

Returns:

  • const QVector< int > & — Grid dimensions {nx, ny, nz}; empty if no shape was set.

hasShape()​

Check whether the grid shape has been set.

Returns:

  • bool — True if the shape holds exactly three dimensions.

toVolume(timeIdx)​

Extract a 3D volume for a given time point, filling the grid with zeros where no source is active.

Parameters:

  • timeIdx : int Time sample index.

Returns:

  • Eigen::VectorXd — Flattened volume (nxnynz, x fastest like volume source-space vertex numbers) with values at active voxels.

centreOfMass(timeIdx)​

Compute the centre of mass of the activity at a given time point.

Parameters:

  • timeIdx : int Time sample index.

Returns:

  • Eigen::Vector3d — 3D position (x, y, z) in voxel coordinates, or (0,0,0) if no activity.

Example​

Used in examples​

ex_inv_api​

Inverse library: minimum-norm estimates, resolution matrices, label time courses, sparse solvers.

src/examples/ex_inv_api/main.cpp, line 204
// A volume estimate keeps the grid shape, so a time slice can be written back into the full grid.
InvVolumeSourceEstimate volumeStc(stc.data.topRows(4), VectorXi::LinSpaced(4, 0, 6), stc.tmin, stc.tstep);
volumeStc.setShape({2, 2, 2}); // 8 voxels, 4 of them sources
const VectorXd grid = volumeStc.toVolume(200);
ok &= expect(grid.size() == 8 && grid(0) == stc.data(0, 200) && grid(6) == stc.data(3, 200) && grid(1) == 0.0,
             "InvVolumeSourceEstimate: source values land on their voxels, the rest of the grid is zero");

Authors of this file​