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InvGuessData

Namespace: INVLIB  ·  Library: Inverse Library

#include <inv/inv_guess_data.h>

class INVLIB::InvGuessData

Implements InvGuessData (Replaces *guessData,guessDataRec struct of MNE-C fit_types.h).

Precomputed guess point grid with forward fields for initial dipole position candidates.

src/examples/ex_inv_dipole_fit/main.cpp
// MEG channels and SSP projectors from the sample file, sphere at (0, 0, 40) mm, ad-hoc noise
// (5e-13 T/m gradiometers, 20 fT magnetometers).
Vector3f r0(0.0f, 0.0f, 0.04f);
std::unique_ptr<InvDipoleFitData> fitData(InvDipoleFitData::setup_dipole_fit_data(
    QString(), sampleAve, QString(), &r0, nullptr, false, QString(), QString(),
    5e-13f, 20e-15f, 0.2e-6f, 0.1f, 0.1f, 0.1f, false, {sampleAve}, true, false));
MatrixXf gain(fitData->nmeg, 3);
const bool fieldOk = InvDipoleFitData::compute_dipole_field(*fitData, truePos, false, gain) == 0; // projected, not whitened
VectorXf field = gain * trueMoment;

InvGuessData guesses(QString(), QString(), 0.0f, 0.02f, 0.015f, fitData.get(), 0.08f); // 15 mm grid in an 80 mm sphere
std::unique_ptr<InvDipoleForward> atTruth(InvDipoleFitData::dipole_forward_one(fitData.get(), truePos, nullptr));
InvEcd dipole;
VectorXf b = field; // fit_one projects and whitens in place
const bool fitted = InvDipoleFitData::fit_one(fitData.get(), &guesses, 0.0f, b, false, dipole);

Public Methods​

InvGuessData()​

Constructs the Guess Data Refactored: new_guess_data (dipole_fit_setup.c).

InvGuessData()​

Deleted — non-copyable due to unique_ptr members.

operator=()​

InvGuessData(guessname, guess_surfname, mindist, exclude, grid, f, guessrad)​

Constructs the Guess Data from given Data Refactored: make_guess_data (dipole_fit_setup.c).

Parameters:

  • guessname : const QString & File with a predefined guess point set (empty = build a grid).

  • guess_surfname : const QString & Surface file bounding the guess grid (empty = inner skull of the BEM, or a sphere).

  • mindist : float Minimum distance of guess points from the bounding surface (m).

  • exclude : float Exclude guess points closer than this to the sphere origin (m).

  • grid : float Spacing of the guess grid (m).

  • f : *InvDipoleFitData ** Dipole fit data providing the forward model.

  • guessrad : float Radius of the spherical guess volume when no surface bounds it (m).

~InvGuessData()​

Destroys the Guess Data description Refactored: free_guess_data (dipole_fit_setup.c).

compute_guess_fields(f)​

Once the guess locations have been set up we can compute the fields Refactored: compute_guess_fields (dipole_fit_setup.c).

Parameters:

Returns:

  • bool — true when successful.

Example​

Used in examples​

ex_inv_dipole_fit​

Inverse library: equivalent current dipole fitting in a sphere model.

src/examples/ex_inv_dipole_fit/main.cpp, line 106
InvGuessData guesses(QString(), QString(), 0.0f, 0.02f, 0.015f, fitData.get(), 0.08f); // 15 mm grid in an 80 mm sphere
std::unique_ptr<InvDipoleForward> atTruth(InvDipoleFitData::dipole_forward_one(fitData.get(), truePos, nullptr));
InvEcd dipole;
VectorXf b = field; // fit_one projects and whitens in place
const bool fitted = InvDipoleFitData::fit_one(fitData.get(), &guesses, 0.0f, b, false, dipole);
ok &= expect(fieldOk && fitted && fitData->nmeg == 305 && guesses.nguess == 627 && atTruth && atTruth->sing.size() == 3 && dipole.valid && (dipole.rd - truePos).norm() < 1e-3f && (1e9 * dipole.Q.cast<double>() - mneMomentNAm).norm() < 0.02 * mneMomentNAm.norm() && dipole.good > 0.9999f,
             "InvDipoleFitData/InvGuessData/InvDipoleForward/InvEcd: one sample fits the dipole like mne.fit_dipole");

Authors of this file​