LongECModels.h

/*! \file ECModels.h
    \brief Contains declaration of classes that implements models for long time-constant eddy currents.

    \author Jesper Andersson
    \version 1.0b, Oct., 2022.
*/
// Declarations of classes that implements a hirearchy
// of models for long-time constant fields from eddy 
// currents induced by diffusion gradients.
//
// LongECModels.h
//
// Jesper Andersson, FMRIB Image Analysis Group
//
// Copyright (C) 2022 University of Oxford
//

#ifndef LongECModels_h
#define LongECModels_h

#include <cstdlib>
#include <string>
#include <vector>
#include <cmath>
#include <memory>
#include "armawrap/newmat.h"
#include "newimage/newimageall.h"
#include "miscmaths/miscmaths.h"
#include "EddyHelperClasses.h"

// Cumbersome forward declaration of nlohmann::json to avoid exposing it to the nvcc compiler
// I _hope_ the macro below doesn't change in json.hpp
#ifndef INCLUDE_NLOHMANN_JSON_HPP_
namespace nlohmann
{
  class json;
}
#endif

namespace EDDY {

/****************************************************************//**
*
* \brief Translates an EC time constant and intercept to weights
*
* Given TR, an EDDY::MultiBandGroup object and parameters
* consisting of time-constant (half-life in seconds), and
* scale factor/intercept it will return a vector of weights 
* for the current and the following volume eddy current-induced 
* field. 
* This is a helper class for two of the models below. 
*
********************************************************************/
class EC_TimeAndIntercept2Weights
{
public:
  EC_TimeAndIntercept2Weights(double TR, const MultiBandGroups& mbg) EddyTry : _TR(TR), _mbg(mbg) { } EddyCatch
  /// Get weights for EC-field from previous volume,
  arma::colvec GetWeightsForPrevious(double Thl,            // Half-life in seconds
				     double Intcpt) const;  // Intercept
  /// Get weights for EC field from current volume.
  arma::colvec GetWeightsForCurrent(double Thl,             // Half-life in seconds
				    double Intcpt) const;   // Intercept
  /// Return the number of MB-groups
  unsigned int NGroups() const EddyTry { return(_mbg.NGroups()); } EddyCatch  
private:
  const double          _TR;    /// Repetition time
  const MultiBandGroups _mbg;   /// Multi-band information 
};

/****************************************************************//**
*
* \brief This class translates an EC time constant to weights
*
* Given TR, an EDDY::MultiBandGroup object and a time-constant 
* (half-life in seconds) of the eddy currents it will return
* a vector of weights for the previous and the current volume
* eddy current-induced field. This is a helper class for two of
* the models below.
*
* It is currently retired in favour of the model above. 
*
********************************************************************/
class EC_TimeConst2Weights
{
public:
  EC_TimeConst2Weights(double TR, const MultiBandGroups& mbg) EddyTry : _TR(TR), _mbg(mbg) { } EddyCatch
  /// Get weights for EC field from previous volume. Thl: Half life in seconds
  arma::colvec GetWeightsForPrevious(double Thl) const;
  /// Get weights for EC field from current volume. Thl: Half life in seconds
  arma::colvec GetWeightsForCurrent(double Thl) const;
  /// Return the number of MB-groups
  unsigned int NGroups() const EddyTry { return(_mbg.NGroups()); } EddyCatch
private:
  const double          _TR;    /// Repetition time
  const MultiBandGroups _mbg;   /// Multi-band information
  void calculate_weights(double Thl,                       // Half life in seconds
			 arma::colvec& prev,               // Weights for EC from previous volume
			 arma::colvec& curr) const;        // Weights for EC from current volume
};

/****************************************************************//**
*
* \brief This class manages the parameters for the long time-constant
* (time varying) eddy currents.
*
* This class manages the parameters for the long time-constant
* (time varying) eddy currents. I have chosen to _not_ use the 
* strategy of a virtual base class, as I do with ECModel below,
* and instead have if-else blocks in the methods. This is because
* I want some of the methods to be friends of ECScan, and I don't
* want to have to friend declare every new subclass.
*
* All the Long EC models are based on the same assumption that 
* the first few MB-groups of a volume experiences residual EC
* from the previous volume, and also that those same first few
* volumes does not yet experince the full EC-field from the 
* diffusion gradient of the current volume.
* There are four concrete subclasses of the pure virtual 
* parent class. They differ in if they model the weights directly
* or through a model with a time-constant. They also differ in
* if they model the different volumes individually, or if they
* assume that the effects are the same across all volumes.
*
********************************************************************/

class ECScan;        // Forward declaration to allow us to declare ECScan as parameter to functions
class ECScanManager; // Forward declaration to allow us to declare ECScanManager as parameter to functions

class LongECModel
{
public:
  LongECModel() EddyTry {} EddyCatch
  ~LongECModel() {}
  /// Returns the model
  virtual LongECModelType Model() const = 0;
  /// Returns true for models that estimate individual parameters for each volume
  virtual bool IsIndividual() const = 0;
  /// Returns true for models that estimate joint parameters for all volumes
  virtual bool IsJoint() const = 0;
  /// Returns true if model estimates weights directly
  virtual bool EstimatesWeights() const = 0;
  /// Returns true if model estimates time constant/constants
  virtual bool EstimatesTimeConst() const = 0;
  /// Returns the number of MB-groups
  virtual unsigned int NGroups() const = 0;
  /// Return number of derivatives for a single scan
  virtual int NDerivs() const = 0;
  /// Gets the value of a single parameter (which has derivative) for scan sc.
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not check for agreement between the scan and the model.
  virtual double GetDerivParam(const EDDY::ECScan& sc, unsigned int i, unsigned int s) const = 0;
  /// Gets suitable scale for numerical derivative for parameter i
  virtual double GetDerivScale(unsigned int i) const = 0;
  /// Sets the value of a single parameter (which has a derivative) for scan sc
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not set the corresponding parameter in the model, only in the scan.
  virtual void SetDerivParam(ECScan& sc, unsigned int i, unsigned int s, double val) const = 0;
  /// Get weight for diagonal of Hessian
  virtual double GetLevenbergLambda(unsigned int s) const = 0;
  /// Set weight for diagonal of Hessian
  virtual void SetLevenbergLambda(unsigned int s, double lambda) = 0;
  /// Returns all the parameters of the model
  virtual std::vector<arma::colvec> GetParameters(const ECScanManager& sm) const = 0;
  /// Returns the parameters for a single volume
  /// N.B. that the index i implicitly assumes ScanType st==ScanType::Any
  virtual arma::colvec GetParameters(const ECScan& sc, unsigned int s) const = 0;
  /// Updates all the parameters of the model. This is the method that should be used for setting.
  virtual void UpdateParameters(ECScanManager& sm, const std::vector<arma::colvec>& update) = 0;
  /// Updates the parameters for a single volume. This is the method to use when rolling back updates on individual volumes.
  virtual void UpdateParameters(ECScan& sc, unsigned int s, const arma::colvec& update) = 0;
  /// Return a json-struct report and (optionally) write a plain ascii text file
  virtual nlohmann::json WriteReport(const ECScanManager& sm, const std::string& fname, bool write_old_style_file) const = 0;
};

//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
//
// Class IndividualWeightsModel
//
// This class models the weights directly on a volume-by-volume
// basis.
//
//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

class IndividualWeightsModel : public LongECModel
{
public:
  IndividualWeightsModel(ECScanManager& sm);
  ~IndividualWeightsModel() {}
  /// Returns the model
  LongECModelType Model() const EddyTry { return(LongECModelType::Individual); } EddyCatch
  /// Returns true for models that estimate individual parameters for each volume
  bool IsIndividual() const EddyTry { return(true); } EddyCatch
  /// Returns true for models that estimate joint parameters for all volumes
  bool IsJoint() const EddyTry { return(!IsIndividual()); } EddyCatch
  /// Returns true if model estimates weights directly
  bool EstimatesWeights() const EddyTry { return(true); } EddyCatch
  /// Returns true if model estimates time constant/constants
  bool EstimatesTimeConst() const EddyTry { return(!EstimatesWeights()); } EddyCatch
  /// Returns the number of MB-groups
  unsigned int NGroups() const EddyTry { return(_ngroups); } EddyCatch
  /// Return number of derivatives for a single scan
  int NDerivs() const EddyTry { return(2*_ngroups); } EddyCatch
  /// Gets the value of a single parameter (which has derivative) for scan sc.
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not check for agreement between the scan and the model.
  double GetDerivParam(const EDDY::ECScan& sc, unsigned int i, unsigned int s) const;
  /// Gets suitable scale for numerical derivative for parameter i
  double GetDerivScale(unsigned int i) const;
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not set the corresponding parameter in the model, only in the scan.
  /// Sets the value of a single parameter (which has a derivative) for scan sc
  void SetDerivParam(ECScan& sc, unsigned int i, unsigned int s, double val) const;
  /// Get weight for diagonal of Hessian
  double GetLevenbergLambda(unsigned int s) const;
  /// Set weight for diagonal of Hessian
  void SetLevenbergLambda(unsigned int s, double lambda);
  /// Returns all the parameters of the model
  std::vector<arma::colvec> GetParameters(const ECScanManager& sm) const;
  /// Returns the parameters for a single volume
  /// N.B. that the index i implicitly assumes ScanType st==ScanType::Any
  arma::colvec GetParameters(const ECScan& sc, unsigned int s) const;
  /// Updates all the parameters of the model. N.B. that "update" means that the update is added to the current parameters.
  void UpdateParameters(ECScanManager& sm, const std::vector<arma::colvec>& update);
  /// Updates the parameters for a single volume. This is the method to use when rolling back updates on individual volumes.
  /// N.B. that "update" means that the update is added to the current parameters.
  /// N.B. that the index s implicitly assumes ScanType st==ScanType::Any
  void UpdateParameters(ECScan& sc, unsigned int s, const arma::colvec& update);
  /// Return a json-struct report and (optionally) write a plain ascii text file
  nlohmann::json WriteReport(const ECScanManager& sm, const std::string& fname, bool write_old_style_file) const;
private:
  unsigned int               _nscans;
  unsigned int               _ngroups;
  std::vector<arma::colvec>  _prev;
  std::vector<arma::colvec>  _curr;
  std::vector<double>        _ll; // Levenberg lambda
  
  bool model_and_scan_agree(const ECScan& sc, unsigned int s) const;
};

//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
//
// Class IndividualTimeConstantsModel
//
// This class models the time constants (half-life in seconds)
// and intercept on a volume-by-volume basis.
//
//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

class IndividualTimeConstantsModel : public LongECModel
{
public:
  IndividualTimeConstantsModel(ECScanManager& sm);
  ~IndividualTimeConstantsModel() {}
  /// Returns the model
  LongECModelType Model() const EddyTry { return(LongECModelType::IndividualTimeConstant); } EddyCatch
  /// Returns true for models that estimate individual parameters for each volume
  bool IsIndividual() const EddyTry { return(true); } EddyCatch
  /// Returns true for models that estimate joint parameters for all volumes
  bool IsJoint() const EddyTry { return(!IsIndividual()); } EddyCatch
  /// Returns true if model estimates weights directly
  bool EstimatesWeights() const EddyTry { return(false); } EddyCatch
  /// Returns true if model estimates time constant/constants
  bool EstimatesTimeConst() const EddyTry { return(!EstimatesWeights()); } EddyCatch
  /// Returns the number of MB-groups
  unsigned int NGroups() const EddyTry { return(_tai2w.NGroups()); } EddyCatch
  /// Return number of derivatives for a single scan
  int NDerivs() const EddyTry { return(4); } EddyCatch
  /// Gets the value of a single parameter (which has derivative) for scan sc.
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not check for agreement between the scan and the model.
  double GetDerivParam(const EDDY::ECScan& sc, unsigned int i, unsigned int s) const;
  /// Gets suitable scale for numerical derivative for parameter i
  double GetDerivScale(unsigned int i) const;
  /// Sets the value of a single parameter (which has a derivative) for scan sc
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not set the corresponding parameter in the model, only in the scan.
  void SetDerivParam(ECScan& sc, unsigned int i, unsigned int s, double val) const;
  /// Get weight for diagonal of Hessian
  double GetLevenbergLambda(unsigned int s) const;
  /// Set weight for diagonal of Hessian
  void SetLevenbergLambda(unsigned int s, double lambda);
  /// Returns all the parameters of the model
  std::vector<arma::colvec> GetParameters(const ECScanManager& sm) const;
  /// Returns the parameters for a single volume
  /// N.B. that the index i implicitly assumes ScanType st==ScanType::Any
  arma::colvec GetParameters(const ECScan& sc, unsigned int s) const;
  /// Updates all the parameters of the model. N.B. that "update" means that the update is added to the current parameters.
  void UpdateParameters(ECScanManager& sm, const std::vector<arma::colvec>& update);
  /// Updates the parameters for a single volume. This is the method to use when rolling back updates on individual volumes.
  /// N.B. that "update" means that the update is added to the current parameters.
  /// N.B. that the index s implicitly assumes ScanType st==ScanType::Any
  void UpdateParameters(ECScan& sc, unsigned int s, const arma::colvec& update);
  /// Return a json-struct report and (optionally) write a plain ascii text file
  nlohmann::json WriteReport(const ECScanManager& sm, const std::string& fname, bool write_old_style_file) const;
private:
  unsigned int                 _nscans;
  EC_TimeAndIntercept2Weights  _tai2w;
  std::vector<arma::colvec>    _par;       // Vector of [previous[TC Intercept] current[TC Intercept]]]
  std::vector<double>          _ll;        // Levenberg lambda

  bool model_and_scan_agree(const ECScan& sc, unsigned int s) const;
};

//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
//
// Class JointWeightsModel
//
// This class models the weights jointly across all volumes.
//
//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

class JointWeightsModel : public LongECModel
{
public:
  JointWeightsModel(ECScanManager& sm);
  ~JointWeightsModel() {}
  /// Returns the model
  LongECModelType Model() const EddyTry { return(LongECModelType::Joint); } EddyCatch
  /// Returns true for models that estimate individual parameters for each volume
  bool IsIndividual() const EddyTry { return(false); } EddyCatch
  /// Returns true for models that estimate joint parameters for all volumes
  bool IsJoint() const EddyTry { return(!IsIndividual()); } EddyCatch
  /// Returns true if model estimates weights directly
  bool EstimatesWeights() const EddyTry { return(true); } EddyCatch
  /// Returns true if model estimates time constant/constants
  bool EstimatesTimeConst() const EddyTry { return(!EstimatesWeights()); } EddyCatch
  /// Returns the number of MB-groups
  unsigned int NGroups() const EddyTry { return(_ngroups); } EddyCatch
  /// Return number of derivatives for a single scan
  int NDerivs() const EddyTry { return(2*_ngroups); } EddyCatch
  /// Gets the value of a single parameter (which has derivative) for scan sc.
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not check for agreement between the scan and the model.
  double GetDerivParam(const EDDY::ECScan& sc, unsigned int i, unsigned int s) const;
  /// Gets suitable scale for numerical derivative for parameter i
  double GetDerivScale(unsigned int i) const;
  /// Sets the value of a single parameter (which has a derivative) for scan sc
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not set the corresponding parameter in the model, only in the scan.
  void SetDerivParam(ECScan& sc, unsigned int i, unsigned int s, double val) const;
  /// Get weight for diagonal of Hessian
  double GetLevenbergLambda(unsigned int s) const;
  /// Set weight for diagonal of Hessian
  void SetLevenbergLambda(unsigned int s, double lambda);
  /// Returns all the parameters of the model
  std::vector<arma::colvec> GetParameters(const ECScanManager& sm) const;
  /// Returns the parameters for a single volume
  /// N.B. that the index i implicitly assumes ScanType st==ScanType::Any
  arma::colvec GetParameters(const ECScan& sc, unsigned int s) const;
  /// Updates all the parameters of the model. N.B. that "update" means that the update is added to the current parameters.
  void UpdateParameters(ECScanManager& sm, const std::vector<arma::colvec>& update);
  /// Updates the parameters for a single volume. This is the method to use when rolling back updates on individual volumes.
  /// N.B. that "update" means that the update is added to the current parameters.
  /// N.B. that the index s implicitly assumes ScanType st==ScanType::Any
  void UpdateParameters(ECScan& sc, unsigned int s, const arma::colvec& update);
  /// Return a json-struct report and (optionally) write a plain ascii text file
  nlohmann::json WriteReport(const ECScanManager& sm, const std::string& fname, bool write_old_style_file) const;
private:
  unsigned int               _nscans;
  unsigned int               _ngroups;
  arma::colvec               _prev;
  arma::colvec               _curr;
  double                     _ll;     // Levenberg lambda

  bool model_and_scan_agree(const ECScan& sc, unsigned int s) const;
};

//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
//
// Class JointTimeConstantModel
//
// This class models the time-constant (half-life in seconds) 
// jointly across all volumes.
//
//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

class JointTimeConstantModel : public LongECModel
{
public:
  JointTimeConstantModel(ECScanManager& sm);
  ~JointTimeConstantModel() {}
  /// Returns the model
  LongECModelType Model() const EddyTry { return(LongECModelType::JointTimeConstant); } EddyCatch
  /// Returns true for models that estimate individual parameters for each volume
  bool IsIndividual() const EddyTry { return(false); } EddyCatch
  /// Returns true for models that estimate joint parameters for all volumes
  bool IsJoint() const EddyTry { return(!IsIndividual()); } EddyCatch
  /// Returns true if model estimates weights directly
  bool EstimatesWeights() const EddyTry { return(false); } EddyCatch
  /// Returns true if model estimates time constant/constants
  bool EstimatesTimeConst() const EddyTry { return(!EstimatesWeights()); } EddyCatch
  /// Returns the number of MB-groups
  unsigned int NGroups() const EddyTry { return(_tai2w.NGroups()); } EddyCatch
  /// Return number of derivatives for a single scan
  int NDerivs() const EddyTry { return(1); } EddyCatch
  /// Gets the value of a single parameter (which has derivative) for scan sc.
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not check for agreement between the scan and the model.
  double GetDerivParam(const EDDY::ECScan& sc, unsigned int i, unsigned int s) const;
  /// Gets suitable scale for numerical derivative for parameter i
  double GetDerivScale(unsigned int i) const;
  /// Sets the value of a single parameter (which has a derivative) for scan sc
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not set the corresponding parameter in the model, only in the scan.
  void SetDerivParam(ECScan& sc, unsigned int i, unsigned int s, double val) const;
  /// Get weight for diagonal of Hessian
  double GetLevenbergLambda(unsigned int s) const;
  /// Set weight for diagonal of Hessian
  void SetLevenbergLambda(unsigned int s, double lambda);
  /// Returns all the parameters of the model
  std::vector<arma::colvec> GetParameters(const ECScanManager& sm) const;
  /// Returns the parameters for a single volume
  /// N.B. that the index i implicitly assumes ScanType st==ScanType::Any
  arma::colvec GetParameters(const ECScan& sc, unsigned int s) const;
  /// Updates all the parameters of the model. N.B. that "update" means that the update is added to the current parameters.
  void UpdateParameters(ECScanManager& sm, const std::vector<arma::colvec>& update);
  /// Updates the parameters for a single volume. This is the method to use when rolling back updates on individual volumes.
  /// N.B. that "update" means that the update is added to the current parameters.
  /// N.B. that the index s implicitly assumes ScanType st==ScanType::Any
  void UpdateParameters(ECScan& sc, unsigned int s, const arma::colvec& update);
  /// Return a json-struct report and (optionally) write a plain ascii text file
  nlohmann::json WriteReport(const ECScanManager& sm, const std::string& fname, bool write_old_style_file) const;
private:
  unsigned int                 _nscans;
  EC_TimeAndIntercept2Weights  _tai2w;
  arma::colvec                 _par;      // previous[TC Intercept] current[TC Intercept]
  double                       _ll;       // Levenberg lambda

  bool model_and_scan_agree(const ECScan& sc, unsigned int s) const;
};

//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
//
// Class NoLongECModel
//
// This is a "null-model" for the cases where we don't want to
// model long eddy currents.
//
//@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

class NoLongECModel : public LongECModel
{
public:
  NoLongECModel() {}
  ~NoLongECModel() {}
  /// Returns the model
  LongECModelType Model() const EddyTry { return(LongECModelType::None); } EddyCatch
  /// Returns true for models that estimate individual parameters for each volume
  bool IsIndividual() const EddyTry { return(false); } EddyCatch
  /// Returns true for models that estimate joint parameters for all volumes
  bool IsJoint() const EddyTry { return(false); } EddyCatch
  /// Returns true if model estimates weights directly
  bool EstimatesWeights() const EddyTry { return(false); } EddyCatch
  /// Returns true if model estimates time constant/constants
  bool EstimatesTimeConst() const EddyTry { return(false); } EddyCatch
  /// Returns the number of MB-groups
  unsigned int NGroups() const EddyTry { 
    throw EddyException("NoLongECModel::NGroups: unknown number of groups");
  } EddyCatch
  /// Return number of derivatives for a single scan
  int NDerivs() const EddyTry { return(0); } EddyCatch
  /// Gets the value of a single parameter (which has derivative) for scan sc.
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not check for agreement between the scan and the model.
  double GetDerivParam(const EDDY::ECScan& sc, unsigned int i, unsigned int s) const EddyTry {
    throw EddyException("NoLongECModel::GetDerivParam: model has no parameters");
  } EddyCatch
  /// Gets suitable scale for numerical derivative for parameter i
  double GetDerivScale(unsigned int i) const EddyTry {
    throw EddyException("NoLongECModel::GetDerivScale: model has no parameters");
  } EddyCatch
  /// Sets the value of a single parameter (which has a derivative) for scan sc
  /// It is intended for use on temporary copies of the scan sc, so this function 
  /// does not set the corresponding parameter in the model, only in the scan.
  void SetDerivParam(ECScan& sc, unsigned int i, unsigned int s, double val) const EddyTry {
    throw EddyException("NoLongECModel::SetDerivParam: model has no parameters");
  } EddyCatch
  /// Get weight for diagonal of Hessian
  double GetLevenbergLambda(unsigned int s) const EddyTry {
    throw EddyException("NoLongECModel::GetLevenbergLambda: model has no lambda");
  } EddyCatch
  /// Set weight for diagonal of Hessian
  virtual void SetLevenbergLambda(unsigned int s, double lambda) EddyTry {
    throw EddyException("NoLongECModel::SetLevenbergLambda: model has no lambda");
  } EddyCatch
  /// Returns all the parameters of the model
  std::vector<arma::colvec> GetParameters(const ECScanManager& sm) const EddyTry {
    throw EddyException("NoLongECModel::GetParameters(sm): model has no parameters");
  } EddyCatch
  /// Returns the parameters for a single volume
  /// N.B. that the index i implicitly assumes ScanType st==ScanType::Any
  arma::colvec GetParameters(const ECScan& sc, unsigned int s) const EddyTry {
    throw EddyException("NoLongECModel::GetParameters(sc,s): model has no parameters");
  } EddyCatch
  /// Updates all the parameters of the model. N.B. that "update" means that the update is added to the current parameters.
  void UpdateParameters(ECScanManager& sm, const std::vector<arma::colvec>& update) EddyTry {
    throw EddyException("NoLongECModel::UpdateParameters(sm,update): model has no parameters");
  } EddyCatch
  /// Updates the parameters for a single volume. This is the method to use when rolling back updates on individual volumes.
  /// N.B. that "update" means that the update is added to the current parameters.
  /// N.B. that the index s implicitly assumes ScanType st==ScanType::Any
  void UpdateParameters(ECScan& sc, unsigned int s, const arma::colvec& update) EddyTry {
    throw EddyException("NoLongECModel::UpdateParameters(sc,s,update): model has no parameters");
  } EddyCatch
  nlohmann::json WriteReport(const ECScanManager& sm, const std::string& fname, bool write_old_style_file) const;
};


} // End namespace EDDY

#endif // End #ifndef LongECModels_h