Examples with VCUnitDefinition cbit.vcell.units.VCUnitDefinition used on opensource projects

Example 31 with VCUnitDefinition

use of cbit.vcell.units.VCUnitDefinition in project vcell by virtualcell.

the class SpeciesContextSpec method initializeForSpatial.

public void initializeForSpatial() {
    if (getDiffusionParameter() != null && getDiffusionParameter().getExpression() != null && getDiffusionParameter().getExpression().isZero()) {
        Expression e = null;
        ModelUnitSystem modelUnitSystem = getSimulationContext().getModel().getUnitSystem();
        VCUnitDefinition micronsqpersecond = modelUnitSystem.getInstance("um2.s-1");
        if (speciesContext.getStructure() instanceof Feature) {
            RationalNumber rn = RationalNumber.getApproximateFraction(micronsqpersecond.convertTo(10, getDiffusionParameter().getUnitDefinition()));
            e = new Expression(rn.doubleValue());
        } else if (speciesContext.getStructure() instanceof Membrane) {
            RationalNumber rn = RationalNumber.getApproximateFraction(micronsqpersecond.convertTo(0.1, getDiffusionParameter().getUnitDefinition()));
            e = new Expression(rn.doubleValue());
        } else {
            RationalNumber rn = RationalNumber.getApproximateFraction(micronsqpersecond.convertTo(1.0, getDiffusionParameter().getUnitDefinition()));
            e = new Expression(rn.doubleValue());
        }
        try {
            getDiffusionParameter().setExpression(e);
        } catch (ExpressionBindingException e1) {
            e1.printStackTrace();
            throw new RuntimeException("Error while initializing diffusion rate, " + e1.getMessage());
        }
    }
}

Example 32 with VCUnitDefinition

use of cbit.vcell.units.VCUnitDefinition in project vcell by virtualcell.

the class SpeciesContextSpec method getLengthPerTimeUnit.

private VCUnitDefinition getLengthPerTimeUnit() {
    ModelUnitSystem modelUnitSystem = getSimulationContext().getModel().getUnitSystem();
    VCUnitDefinition lengthPerTimeUnit = modelUnitSystem.getLengthUnit().divideBy(modelUnitSystem.getTimeUnit());
    return lengthPerTimeUnit;
}

Example 33 with VCUnitDefinition

use of cbit.vcell.units.VCUnitDefinition in project vcell by virtualcell.

the class StochMathMapping method addJumpProcesses.

private void addJumpProcesses(VariableHash varHash, GeometryClass geometryClass, SubDomain subDomain) throws ExpressionException, ModelException, MappingException, MathException {
    // set up jump processes
    // get all the reactions from simulation context
    // ReactionSpec[] reactionSpecs = simContext.getReactionContext().getReactionSpecs();---need to take a look here!
    ModelUnitSystem modelUnitSystem = getSimulationContext().getModel().getUnitSystem();
    ReactionSpec[] reactionSpecs = getSimulationContext().getReactionContext().getReactionSpecs();
    for (ReactionSpec reactionSpec : reactionSpecs) {
        if (reactionSpec.isExcluded()) {
            continue;
        }
        // get the reaction
        ReactionStep reactionStep = reactionSpec.getReactionStep();
        Kinetics kinetics = reactionStep.getKinetics();
        // probability parameter from modelUnitSystem
        VCUnitDefinition probabilityParamUnit = modelUnitSystem.getStochasticSubstanceUnit().divideBy(modelUnitSystem.getTimeUnit());
        // Different ways to deal with simple reactions and flux reactions
        if (// simple reactions
        reactionStep instanceof SimpleReaction) {
            // check the reaction rate law to see if we need to decompose a reaction(reversible) into two jump processes.
            // rate constants are important in calculating the probability rate.
            // for Mass Action, we use KForward and KReverse,
            // for General Kinetics we parse reaction rate J to see if it is in Mass Action form.
            Expression forwardRate = null;
            Expression reverseRate = null;
            if (kinetics.getKineticsDescription().equals(KineticsDescription.MassAction) || kinetics.getKineticsDescription().equals(KineticsDescription.General)) {
                Expression rateExp = new Expression(kinetics.getKineticsParameterFromRole(Kinetics.ROLE_ReactionRate), reactionStep.getNameScope());
                Parameter forwardRateParameter = null;
                Parameter reverseRateParameter = null;
                if (kinetics.getKineticsDescription().equals(KineticsDescription.MassAction)) {
                    forwardRateParameter = kinetics.getKineticsParameterFromRole(Kinetics.ROLE_KForward);
                    reverseRateParameter = kinetics.getKineticsParameterFromRole(Kinetics.ROLE_KReverse);
                }
                MassActionSolver.MassActionFunction maFunc = MassActionSolver.solveMassAction(forwardRateParameter, reverseRateParameter, rateExp, reactionStep);
                if (maFunc.getForwardRate() == null && maFunc.getReverseRate() == null) {
                    throw new MappingException("Cannot generate stochastic math mapping for the reaction:" + reactionStep.getName() + "\nLooking for the rate function according to the form of k1*Reactant1^Stoir1*Reactant2^Stoir2...-k2*Product1^Stoip1*Product2^Stoip2.");
                } else {
                    if (maFunc.getForwardRate() != null) {
                        forwardRate = maFunc.getForwardRate();
                    }
                    if (maFunc.getReverseRate() != null) {
                        reverseRate = maFunc.getReverseRate();
                    }
                }
            } else // if it's macro/microscopic kinetics, we'll have them set up as reactions with only forward rate.
            if (kinetics.getKineticsDescription().equals(KineticsDescription.Macroscopic_irreversible) || kinetics.getKineticsDescription().equals(KineticsDescription.Microscopic_irreversible)) {
                Expression Kon = getIdentifierSubstitutions(new Expression(reactionStep.getKinetics().getKineticsParameterFromRole(Kinetics.ROLE_KOn), getNameScope()), reactionStep.getKinetics().getKineticsParameterFromRole(Kinetics.ROLE_Binding_Radius).getUnitDefinition(), geometryClass);
                if (Kon != null) {
                    Expression KonCopy = new Expression(Kon);
                    try {
                        MassActionSolver.substituteParameters(KonCopy, true).evaluateConstant();
                        forwardRate = new Expression(Kon);
                    } catch (ExpressionException e) {
                        throw new MathException(VCellErrorMessages.getMassActionSolverMessage(reactionStep.getName(), "Problem with Kon parameter in " + reactionStep.getName() + ":  '" + KonCopy.infix() + "', " + e.getMessage()));
                    }
                } else {
                    throw new MathException(VCellErrorMessages.getMassActionSolverMessage(reactionStep.getName(), "Kon parameter of " + reactionStep.getName() + " is null."));
                }
            }
            boolean isForwardRatePresent = false;
            boolean isReverseRatePresent = false;
            if (forwardRate != null) {
                isForwardRatePresent = true;
            }
            if (reverseRate != null) {
                isReverseRatePresent = true;
            }
            // we process it as forward reaction
            if ((isForwardRatePresent)) /*|| ((forwardRate == null) && (reverseRate == null))*/
            {
                // get jump process name
                String jpName = TokenMangler.mangleToSName(reactionStep.getName());
                // get probability
                Expression exp = null;
                // reactions are of mass action form
                exp = getProbabilityRate(reactionStep, forwardRate, true);
                ProbabilityParameter probParm = null;
                try {
                    probParm = addProbabilityParameter(PARAMETER_PROBABILITYRATE_PREFIX + jpName, exp, PARAMETER_ROLE_P, probabilityParamUnit, reactionStep);
                } catch (PropertyVetoException pve) {
                    pve.printStackTrace();
                    throw new MappingException(pve.getMessage());
                }
                // add probability to function or constant
                varHash.addVariable(newFunctionOrConstant(getMathSymbol(probParm, geometryClass), getIdentifierSubstitutions(exp, probabilityParamUnit, geometryClass), geometryClass));
                JumpProcess jp = new JumpProcess(jpName, new Expression(getMathSymbol(probParm, geometryClass)));
                // actions
                ReactionParticipant[] reacPart = reactionStep.getReactionParticipants();
                for (int j = 0; j < reacPart.length; j++) {
                    Action action = null;
                    SpeciesCountParameter spCountParam = getSpeciesCountParameter(reacPart[j].getSpeciesContext());
                    if (reacPart[j] instanceof Reactant) {
                        // check if the reactant is a constant. If the species is a constant, there will be no action taken on this species
                        if (// not a constant
                        !simContext.getReactionContext().getSpeciesContextSpec(reacPart[j].getSpeciesContext()).isConstant()) {
                            int stoi = ((Reactant) reacPart[j]).getStoichiometry();
                            action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(-stoi));
                            jp.addAction(action);
                        }
                    } else if (reacPart[j] instanceof Product) {
                        // check if the product is a constant. If the product is a constant, there will be no action taken on this species
                        if (// not a constant
                        !simContext.getReactionContext().getSpeciesContextSpec(reacPart[j].getSpeciesContext()).isConstant()) {
                            int stoi = ((Product) reacPart[j]).getStoichiometry();
                            action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(stoi));
                            jp.addAction(action);
                        }
                    }
                }
                // add jump process to compartment subDomain
                subDomain.addJumpProcess(jp);
            }
            if (// one more jump process for a reversible reaction
            isReverseRatePresent) {
                // get jump process name
                String jpName = TokenMangler.mangleToSName(reactionStep.getName()) + PARAMETER_PROBABILITY_RATE_REVERSE_SUFFIX;
                Expression exp = null;
                // reactions are mass actions
                exp = getProbabilityRate(reactionStep, reverseRate, false);
                ProbabilityParameter probRevParm = null;
                try {
                    probRevParm = addProbabilityParameter(PARAMETER_PROBABILITYRATE_PREFIX + jpName, exp, PARAMETER_ROLE_P_reverse, probabilityParamUnit, reactionStep);
                } catch (PropertyVetoException pve) {
                    pve.printStackTrace();
                    throw new MappingException(pve.getMessage());
                }
                // add probability to function or constant
                varHash.addVariable(newFunctionOrConstant(getMathSymbol(probRevParm, geometryClass), getIdentifierSubstitutions(exp, probabilityParamUnit, geometryClass), geometryClass));
                JumpProcess jp = new JumpProcess(jpName, new Expression(getMathSymbol(probRevParm, geometryClass)));
                // actions
                ReactionParticipant[] reacPart = reactionStep.getReactionParticipants();
                for (int j = 0; j < reacPart.length; j++) {
                    Action action = null;
                    SpeciesCountParameter spCountParam = getSpeciesCountParameter(reacPart[j].getSpeciesContext());
                    if (reacPart[j] instanceof Reactant) {
                        // check if the reactant is a constant. If the species is a constant, there will be no action taken on this species
                        if (// not a constant
                        !simContext.getReactionContext().getSpeciesContextSpec(reacPart[j].getSpeciesContext()).isConstant()) {
                            int stoi = ((Reactant) reacPart[j]).getStoichiometry();
                            action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(stoi));
                            jp.addAction(action);
                        }
                    } else if (reacPart[j] instanceof Product) {
                        // check if the product is a constant. If the product is a constant, there will be no action taken on this species
                        if (// not a constant
                        !simContext.getReactionContext().getSpeciesContextSpec(reacPart[j].getSpeciesContext()).isConstant()) {
                            int stoi = ((Product) reacPart[j]).getStoichiometry();
                            action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(-stoi));
                            jp.addAction(action);
                        }
                    }
                }
                // add jump process to compartment subDomain
                subDomain.addJumpProcess(jp);
            }
        // end of if(isForwardRateNonZero), if(isReverseRateNonRate)
        } else if (// flux reactions
        reactionStep instanceof FluxReaction) {
            // we could set jump processes for general flux rate in forms of p1*Sout + p2*Sin
            if (kinetics.getKineticsDescription().equals(KineticsDescription.General) || kinetics.getKineticsDescription().equals(KineticsDescription.GeneralPermeability)) {
                Expression fluxRate = new Expression(kinetics.getKineticsParameterFromRole(Kinetics.ROLE_ReactionRate), reactionStep.getNameScope());
                // we have to pass the math description para to flux solver, coz somehow math description in simulation context is not updated.
                // forward and reverse rate parameters may be null
                Parameter forwardRateParameter = null;
                Parameter reverseRateParameter = null;
                if (kinetics.getKineticsDescription().equals(KineticsDescription.GeneralPermeability)) {
                    forwardRateParameter = kinetics.getKineticsParameterFromRole(Kinetics.ROLE_Permeability);
                    reverseRateParameter = kinetics.getKineticsParameterFromRole(Kinetics.ROLE_Permeability);
                }
                MassActionSolver.MassActionFunction fluxFunc = MassActionSolver.solveMassAction(forwardRateParameter, reverseRateParameter, fluxRate, (FluxReaction) reactionStep);
                // create jump process for forward flux if it exists.
                Expression rsStructureSize = new Expression(reactionStep.getStructure().getStructureSize(), getNameScope());
                VCUnitDefinition probRateUnit = modelUnitSystem.getStochasticSubstanceUnit().divideBy(modelUnitSystem.getAreaUnit()).divideBy(modelUnitSystem.getTimeUnit());
                Expression rsRateUnitFactor = getUnitFactor(probRateUnit.divideBy(modelUnitSystem.getFluxReactionUnit()));
                if (fluxFunc.getForwardRate() != null && !fluxFunc.getForwardRate().isZero()) {
                    Expression rate = fluxFunc.getForwardRate();
                    // get species expression (depend on structure, if mem: Species/mem_Size, if vol: species*KMOLE/vol_size)
                    if (fluxFunc.getReactants().size() != 1) {
                        throw new MappingException("Flux " + reactionStep.getName() + " should have only one reactant.");
                    }
                    SpeciesContext scReactant = fluxFunc.getReactants().get(0).getSpeciesContext();
                    Expression scConcExpr = new Expression(getSpeciesConcentrationParameter(scReactant), getNameScope());
                    Expression probExp = Expression.mult(rate, rsRateUnitFactor, rsStructureSize, scConcExpr);
                    // jump process name
                    // +"_reverse";
                    String jpName = TokenMangler.mangleToSName(reactionStep.getName());
                    ProbabilityParameter probParm = null;
                    try {
                        probParm = addProbabilityParameter(PARAMETER_PROBABILITYRATE_PREFIX + jpName, probExp, PARAMETER_ROLE_P, probabilityParamUnit, reactionStep);
                    } catch (PropertyVetoException pve) {
                        pve.printStackTrace();
                        throw new MappingException(pve.getMessage());
                    }
                    // add probability to function or constant
                    String ms = getMathSymbol(probParm, geometryClass);
                    Expression is = getIdentifierSubstitutions(probExp, probabilityParamUnit, geometryClass);
                    Variable nfoc = newFunctionOrConstant(ms, is, geometryClass);
                    varHash.addVariable(nfoc);
                    JumpProcess jp = new JumpProcess(jpName, new Expression(getMathSymbol(probParm, geometryClass)));
                    // actions
                    Action action = null;
                    SpeciesContext sc = fluxFunc.getReactants().get(0).getSpeciesContext();
                    if (!simContext.getReactionContext().getSpeciesContextSpec(sc).isConstant()) {
                        SpeciesCountParameter spCountParam = getSpeciesCountParameter(sc);
                        action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(-1));
                        jp.addAction(action);
                    }
                    sc = fluxFunc.getProducts().get(0).getSpeciesContext();
                    if (!simContext.getReactionContext().getSpeciesContextSpec(sc).isConstant()) {
                        SpeciesCountParameter spCountParam = getSpeciesCountParameter(sc);
                        action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(1));
                        jp.addAction(action);
                    }
                    subDomain.addJumpProcess(jp);
                }
                // create jump process for reverse flux if it exists.
                if (fluxFunc.getReverseRate() != null && !fluxFunc.getReverseRate().isZero()) {
                    // jump process name
                    String jpName = TokenMangler.mangleToSName(reactionStep.getName()) + PARAMETER_PROBABILITY_RATE_REVERSE_SUFFIX;
                    Expression rate = fluxFunc.getReverseRate();
                    // get species expression (depend on structure, if mem: Species/mem_Size, if vol: species*KMOLE/vol_size)
                    if (fluxFunc.getProducts().size() != 1) {
                        throw new MappingException("Flux " + reactionStep.getName() + " should have only one product.");
                    }
                    SpeciesContext scProduct = fluxFunc.getProducts().get(0).getSpeciesContext();
                    Expression scConcExpr = new Expression(getSpeciesConcentrationParameter(scProduct), getNameScope());
                    Expression probExp = Expression.mult(rate, rsRateUnitFactor, rsStructureSize, scConcExpr);
                    ProbabilityParameter probRevParm = null;
                    try {
                        probRevParm = addProbabilityParameter(PARAMETER_PROBABILITYRATE_PREFIX + jpName, probExp, PARAMETER_ROLE_P_reverse, probabilityParamUnit, reactionStep);
                    } catch (PropertyVetoException pve) {
                        pve.printStackTrace();
                        throw new MappingException(pve.getMessage());
                    }
                    // add probability to function or constant
                    varHash.addVariable(newFunctionOrConstant(getMathSymbol(probRevParm, geometryClass), getIdentifierSubstitutions(probExp, probabilityParamUnit, geometryClass), geometryClass));
                    JumpProcess jp = new JumpProcess(jpName, new Expression(getMathSymbol(probRevParm, geometryClass)));
                    // actions
                    Action action = null;
                    SpeciesContext sc = fluxFunc.getReactants().get(0).getSpeciesContext();
                    if (!simContext.getReactionContext().getSpeciesContextSpec(sc).isConstant()) {
                        SpeciesCountParameter spCountParam = getSpeciesCountParameter(sc);
                        action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(1));
                        jp.addAction(action);
                    }
                    sc = fluxFunc.getProducts().get(0).getSpeciesContext();
                    if (!simContext.getReactionContext().getSpeciesContextSpec(sc).isConstant()) {
                        SpeciesCountParameter spCountParam = getSpeciesCountParameter(sc);
                        action = Action.createIncrementAction(varHash.getVariable(getMathSymbol(spCountParam, geometryClass)), new Expression(-1));
                        jp.addAction(action);
                    }
                    subDomain.addJumpProcess(jp);
                }
            }
        }
    // end of if (simplereaction)...else if(fluxreaction)
    }
// end of reaction step loop
}

Example 34 with VCUnitDefinition

use of cbit.vcell.units.VCUnitDefinition in project vcell by virtualcell.

the class StructureAnalyzer method getCorrectedRateExpression.

public Expression getCorrectedRateExpression(ReactionStep reactionStep, ReactionParticipant reactionParticipant, RateType rateType) throws Exception {
    if (reactionParticipant instanceof Catalyst) {
        throw new Exception("Catalyst " + reactionParticipant + " doesn't have a rate for this reaction");
    // return new Expression(0.0);
    }
    double stoich = reactionStep.getStoichiometry(reactionParticipant.getSpeciesContext());
    if (stoich == 0.0) {
        return new Expression(0.0);
    }
    // 
    // make distributed rate with correct stoichiometry for this participant
    // 
    VCUnitDefinition correctedReactionRateUnit = null;
    Expression distribRate = null;
    if (reactionStep.getKinetics() instanceof DistributedKinetics) {
        DistributedKinetics distributedKinetics = (DistributedKinetics) reactionStep.getKinetics();
        KineticsParameter distribReactionRateParameter = distributedKinetics.getReactionRateParameter();
        distribRate = new Expression(distribReactionRateParameter, mathMapping.getNameScope());
        correctedReactionRateUnit = distribReactionRateParameter.getUnitDefinition();
    } else if (reactionStep.getKinetics() instanceof LumpedKinetics) {
        // 
        // need to put this into concentration/time with respect to structure for reaction.
        // 
        Structure.StructureSize structureSize = reactionStep.getStructure().getStructureSize();
        LumpedKinetics lumpedKinetics = (LumpedKinetics) reactionStep.getKinetics();
        KineticsParameter lumpedReactionRateParameter = lumpedKinetics.getLumpedReactionRateParameter();
        Expression lumpedReactionRateExp = new Expression(lumpedReactionRateParameter, mathMapping.getNameScope());
        distribRate = Expression.div(lumpedReactionRateExp, new Expression(structureSize, mathMapping.getNameScope()));
        ;
        correctedReactionRateUnit = lumpedReactionRateParameter.getUnitDefinition().divideBy(structureSize.getUnitDefinition());
    }
    // correct for stoichiometry
    Expression distribRateWithStoich = distribRate;
    if (stoich != 1) {
        distribRateWithStoich = Expression.mult(new Expression(stoich), distribRateWithStoich);
    }
    // flux correction if reaction and reactionParticipant are in different compartments. (not necessarily dimensionless, use KFlux parameter).
    Expression distribRateWithStoichFlux = distribRateWithStoich;
    if (reactionStep.getStructure() != reactionParticipant.getStructure()) {
        StructureMapping reactionSM = mathMapping.getSimulationContext().getGeometryContext().getStructureMapping(reactionStep.getStructure());
        StructureMapping speciesSM = mathMapping.getSimulationContext().getGeometryContext().getStructureMapping(reactionParticipant.getStructure());
        Parameter fluxCorrectionParameter = mathMapping.getFluxCorrectionParameter(reactionSM, speciesSM);
        Expression fluxCorrection = new Expression(fluxCorrectionParameter, mathMapping.getNameScope());
        distribRateWithStoichFlux = Expression.mult(fluxCorrection, distribRateWithStoichFlux);
        correctedReactionRateUnit = correctedReactionRateUnit.multiplyBy(fluxCorrectionParameter.getUnitDefinition());
    }
    // apply unit factor for difference substance
    ModelUnitSystem unitSystem = mathMapping.getSimulationContext().getModel().getUnitSystem();
    VCUnitDefinition timeUnit = unitSystem.getTimeUnit();
    VCUnitDefinition speciesConcUnit = reactionParticipant.getSpeciesContext().getUnitDefinition();
    VCUnitDefinition speciesConcRateUnit = speciesConcUnit.divideBy(timeUnit);
    Expression unitFactor = null;
    if (rateType == RateType.ConcentrationRate) {
        unitFactor = mathMapping.getUnitFactor(speciesConcRateUnit.divideBy(correctedReactionRateUnit));
    } else if (rateType == RateType.ResolvedFluxRate) {
        unitFactor = mathMapping.getUnitFactor(speciesConcRateUnit.multiplyBy(unitSystem.getLengthUnit()).divideBy(correctedReactionRateUnit));
    }
    return Expression.mult(unitFactor, distribRateWithStoichFlux).flatten();
}

Example 35 with VCUnitDefinition

use of cbit.vcell.units.VCUnitDefinition in project vcell by virtualcell.

the class StructureAnalyzer method refreshTotalDependancies.

/**
 * This method was created by a SmartGuide.
 * @param b cbit.vcell.math.Matrix
 * @param vars java.lang.String[]
 */
private void refreshTotalDependancies() throws Exception {
    // 
    for (int v = 0; v < speciesContextMappings.length; v++) {
        speciesContextMappings[v].setDependencyExpression(null);
    }
    if (totalNullSpaceMatrix == null) {
        // System.out.println("the matrix has full rank, there are no dependencies");
        return;
    }
    if (speciesContextMappings.length != totalNullSpaceMatrix.getNumCols()) {
        throw new Exception("varName array not same dimension as b matrix");
    }
    StructureAnalyzer.Dependency[] dependencies = refreshTotalDependancies(totalNullSpaceMatrix, speciesContextMappings, mathMapping, false);
    VCUnitDefinition totalMassUnit = null;
    boolean bIsSpatial = mathMapping.getSimulationContext().getGeometry().getDimension() > 0;
    ModelUnitSystem modelUnitSystem = mathMapping.getSimulationContext().getModel().getUnitSystem();
    if (this instanceof VolumeStructureAnalyzer) {
        if (!bIsSpatial) {
            // VCUnitDefinition.UNIT_umol_um3_per_L; -> VCell vol substance unit
            totalMassUnit = modelUnitSystem.getVolumeSubstanceUnit();
        } else {
            // VCUnitDefinition.UNIT_uM;
            totalMassUnit = modelUnitSystem.getVolumeConcentrationUnit();
        }
    } else if (this instanceof MembraneStructureAnalyzer) {
        if (!bIsSpatial) {
            // VCUnitDefinition.UNIT_molecules;
            totalMassUnit = modelUnitSystem.getMembraneSubstanceUnit();
        } else {
            // VCUnitDefinition.UNIT_molecules_per_um2;
            totalMassUnit = modelUnitSystem.getMembraneConcentrationUnit();
        }
    }
    for (int i = 0; i < dependencies.length; i++) {
        String constantName = dependencies[i].invariantSymbolName;
        Expression constantExp = dependencies[i].conservedMoietyExpression;
        SpeciesContextMapping firstSCM = dependencies[i].speciesContextMapping;
        Expression exp = dependencies[i].dependencyExpression;
        // 
        // store totalMass parameter (e.g. K_xyz_total = xyz_init + wzy_init)
        // 
        GeometryClass geometryClass = mathMapping.getSimulationContext().getGeometryContext().getStructureMapping(firstSCM.getSpeciesContext().getStructure()).getGeometryClass();
        MathMappingParameter totalMassParameter = mathMapping.addMathMappingParameter(constantName, constantExp.flatten(), DiffEquMathMapping.PARAMETER_ROLE_TOTALMASS, totalMassUnit, geometryClass);
        // 
        // store dependency parameter (e.g. xyz = K_xyz_total - wzy)
        // 
        exp.bindExpression(mathMapping);
        firstSCM.setDependencyExpression(exp);
    }
}