Exemplo n.º 1
0
 private double[] PCG(double[,] stiffnessMatrix, double[] forceVector)
 {
     double[] solutionVector = new double[forceVector.Length];
     double[,] preconditioner = new double[stiffnessMatrix.GetLength(0), stiffnessMatrix.GetLength(1)];
     for (int i = 0; i < preconditioner.GetLength(0); i++)
     {
         preconditioner[i, i] = 1 / stiffnessMatrix[i, i];
     }
     double[] residual = VectorOperations.VectorVectorSubtraction(
         forceVector,
         VectorOperations.MatrixVectorProduct(stiffnessMatrix, solutionVector)
         );
     double[] preconVector = VectorOperations.MatrixVectorProduct(preconditioner, residual);
     for (int iter = 0; iter < maxIterations; iter++)
     {
         double[] u = VectorOperations.MatrixVectorProduct(stiffnessMatrix, preconVector);
         double   residualDotOld = VectorOperations.VectorDotProduct(residual, preconVector);
         double   alpha          = residualDotOld / VectorOperations.VectorDotProduct(preconVector, u);
         solutionVector = VectorOperations.VectorVectorAddition(solutionVector, VectorOperations.VectorScalarProductNew(preconVector, alpha));
         residual       = VectorOperations.VectorVectorSubtraction(residual, VectorOperations.VectorScalarProductNew(u, alpha));
         if (VectorOperations.VectorDotProduct(residual, residual) < tolerance)
         {
             break;
         }
         double residualDotNew = VectorOperations.VectorDotProduct(residual, VectorOperations.MatrixVectorProduct(preconditioner, residual));
         double beta           = residualDotNew / residualDotOld;
         preconVector = VectorOperations.VectorVectorAddition(
             VectorOperations.MatrixVectorProduct(preconditioner, residual),
             VectorOperations.VectorScalarProductNew(preconVector, beta)
             );
     }
     return(solutionVector);
 }
Exemplo n.º 2
0
        private double[] LoadControlledNR(double[] forceVector)
        {
            lambda = 1.0 / numberOfLoadSteps;
            double[] incrementDf    = VectorOperations.VectorScalarProductNew(forceVector, lambda);
            double[] solutionVector = new double[forceVector.Length];
            double[] incrementalExternalForcesVector = new double[forceVector.Length];
            double[] tempSolutionVector = new double[solutionVector.Length];
            double[] deltaU             = new double[solutionVector.Length];
            double[] internalForcesTotalVector;
            double[] dU;
            double[] residual;
            double   residualNorm;

            //Assembler.UpdateAccelerations(CalculateAccelerations(InitialValues.InitialAccelerationVector));

            for (int i = 0; i < numberOfLoadSteps; i++)
            {
                incrementalExternalForcesVector = VectorOperations.VectorVectorAddition(incrementalExternalForcesVector, incrementDf);
                Assembler.UpdateDisplacements(solutionVector);

                Assembler.UpdateAccelerations(explicitAcceleration.Values.Last());

                internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();

                double[,] tangentMatrix = CalculateHatMMatrix();
                dU             = LinearSolver.Solve(tangentMatrix, incrementDf);
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, dU);

                Assembler.UpdateDisplacements(solutionVector);
                tangentMatrix             = CalculateHatMMatrix();
                internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();

                residual     = VectorOperations.VectorVectorSubtraction(internalForcesTotalVector, incrementalExternalForcesVector);
                residualNorm = VectorOperations.VectorNorm2(residual);
                int iteration = 0;
                Array.Clear(deltaU, 0, deltaU.Length);
                while (residualNorm > tolerance && iteration < maxIterations)
                {
                    tangentMatrix      = CalculateHatMMatrix();
                    deltaU             = VectorOperations.VectorVectorSubtraction(deltaU, LinearSolver.Solve(tangentMatrix, residual));
                    tempSolutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                    Assembler.UpdateDisplacements(tempSolutionVector);

                    //Assembler.UpdateAccelerations(CalculateAccelerations(solutionVector));

                    internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();
                    residual     = VectorOperations.VectorVectorSubtraction(internalForcesTotalVector, incrementalExternalForcesVector);
                    residualNorm = VectorOperations.VectorNorm2(residual);
                    iteration    = iteration + 1;
                }
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                if (iteration >= maxIterations)
                {
                    Console.WriteLine("Newton-Raphson: Solution not converged at current iterations");
                }
            }

            return(solutionVector);
        }
Exemplo n.º 3
0
        private double[] LoadControlledNR(double[] forceVector)
        {
            double[] incrementDf    = VectorOperations.VectorScalarProductNew(forceVector, lambda);
            double[] solutionVector = localSolutionVector;
            double[] incrementalExternalForcesVector = new double[forceVector.Length];
            double[] tempSolutionVector = new double[solutionVector.Length];
            double[] deltaU             = new double[solutionVector.Length];
            double[] internalForcesTotalVector;
            double[] dU;
            double[] residual;
            double   residualNorm;

            for (int i = 0; i < numberOfLoadSteps; i++)
            {
                incrementalExternalForcesVector = VectorOperations.VectorVectorAddition(incrementalExternalForcesVector, incrementDf);
                discretization.UpdateDisplacements(solutionVector);
                internalForcesTotalVector = discretization.CreateTotalInternalForcesVector();
                double[,] stiffnessMatrix = discretization.CreateTotalStiffnessMatrix();
                //OnConvergenceResult("Newton-Raphson: Solution not converged at load step" + i);
                dU             = linearSolver.Solve(stiffnessMatrix, incrementDf);
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, dU);
                residual       = VectorOperations.VectorVectorSubtraction(internalForcesTotalVector, incrementalExternalForcesVector);
                residualNorm   = VectorOperations.VectorNorm2(residual);
                int iteration = 0;
                Array.Clear(deltaU, 0, deltaU.Length);
                while (residualNorm > Tolerance && iteration < MaxIterations)
                {
                    stiffnessMatrix    = discretization.CreateTotalStiffnessMatrix();
                    deltaU             = VectorOperations.VectorVectorSubtraction(deltaU, linearSolver.Solve(stiffnessMatrix, residual));
                    tempSolutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                    discretization.UpdateDisplacements(tempSolutionVector);
                    internalForcesTotalVector = discretization.CreateTotalInternalForcesVector();
                    residual     = VectorOperations.VectorVectorSubtraction(internalForcesTotalVector, incrementalExternalForcesVector);
                    residualNorm = VectorOperations.VectorNorm2(residual);
                    if (residualNorm <= Tolerance)
                    {
                        OnConvergenceResult("Newton-Raphson: Load Step " + i + " - Solution converged at iteration " + iteration + " - Residual Norm = " + residualNorm);
                    }
                    else
                    {
                        OnConvergenceResult("Newton-Raphson: Load Step " + i + " - Solution not converged at iteration " + iteration + " - Residual Norm = " + residualNorm);
                    }
                    iteration = iteration + 1;
                    //(Application.Current.Windows[0] as MainWindow).LogTool.Text = "ok";
                    //OnConvergenceResult("Newton-Raphson: Solution not converged at load step" + iteration);
                }
                InternalForces.Add(i + 1, internalForcesTotalVector);
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                Solutions.Add(i + 1, solutionVector);
                if (iteration >= MaxIterations)
                {
                    OnConvergenceResult("Newton-Raphson did not converge at Load Step " + i + ". Exiting solution.");
                    LoadStepConvergence.Add("Solution not converged.");
                    break;
                }
                LoadStepConvergence.Add("Solution converged.");
            }
            return(solutionVector);
        }
Exemplo n.º 4
0
 private double[] CalculatePreviousDisplacementVector()
 {
     double[] previousDisp = VectorOperations.VectorVectorAddition(
         VectorOperations.VectorVectorSubtraction(InitialValues.InitialDisplacementVector,
                                                  VectorOperations.VectorScalarProductNew(InitialValues.InitialVelocityVector, timeStep)),
         VectorOperations.VectorScalarProductNew(InitialValues.InitialAccelerationVector, a3));
     return(previousDisp);
 }
Exemplo n.º 5
0
        private double[] BiCGSTAB(double[,] stiffnessMatrix, double[] forceVector)
        {
            double[] solutionVector = new double[forceVector.Length];

            double[] xVector = new double[forceVector.Length];
            double[] pVector = new double[forceVector.Length];
            double[] vVector = new double[forceVector.Length];

            double[,] K = stiffnessMatrix;

            double[] bVector     = forceVector;
            double[] rVector     = VectorOperations.VectorVectorSubtraction(bVector, VectorOperations.MatrixVectorProduct(K, xVector));
            double[] r0hatVector = rVector;

            double rho0 = 1.0;
            double w    = 1.0;
            double a    = 1.0;
            double rho1 = VectorOperations.VectorDotProduct(r0hatVector, rVector);
            double b;

            double[] sVector;
            double[] tVector;
            int      iters = 100;
            double   converged;

            for (int i = 0; i < iters; i++)
            {
                b       = (rho1 / rho0) * (a / w);
                pVector = VectorOperations.VectorVectorAddition(rVector,
                                                                VectorOperations.VectorScalarProductNew(
                                                                    VectorOperations.VectorVectorSubtraction(pVector,
                                                                                                             VectorOperations.VectorScalarProductNew(vVector, w)), b));
                vVector = VectorOperations.MatrixVectorProduct(K, pVector);
                a       = rho1 / VectorOperations.VectorDotProduct(r0hatVector, vVector);
                sVector = VectorOperations.VectorVectorSubtraction(rVector,
                                                                   VectorOperations.VectorScalarProductNew(vVector, a));
                tVector = VectorOperations.MatrixVectorProduct(K, sVector);
                w       = VectorOperations.VectorDotProduct(tVector, sVector) / VectorOperations.VectorDotProduct(tVector, tVector);
                rho0    = rho1;
                rho1    = -w *VectorOperations.VectorDotProduct(r0hatVector, tVector);

                xVector = VectorOperations.VectorVectorAddition(xVector,
                                                                VectorOperations.VectorScalarProductNew(pVector, a));
                xVector = VectorOperations.VectorVectorAddition(xVector,
                                                                VectorOperations.VectorScalarProductNew(sVector, w));
                rVector = VectorOperations.VectorVectorSubtraction(sVector,
                                                                   VectorOperations.VectorScalarProductNew(tVector, w));
                converged = VectorOperations.VectorNorm2(rVector);
                if (i == iters | converged < 0.00000001)
                {
                    break;
                }
            }
            solutionVector = xVector;
            return(solutionVector);
        }
Exemplo n.º 6
0
        private double[] CalculateHatRVector(int i)
        {
            double[,] hatKMatrix = CalculateHatKMatrix();
            double[,] hatMMatrix = CalculateHatMMatrix();
            double[] hatCurrentU  = VectorOperations.MatrixVectorProduct(hatKMatrix, explicitSolution[i - 1]);
            double[] hatPreviousU = VectorOperations.MatrixVectorProduct(hatMMatrix, explicitSolution[i - 2]);

            double[] hatR = VectorOperations.VectorVectorSubtraction(ExternalForcesVector,
                                                                     VectorOperations.VectorVectorAddition(hatCurrentU, hatPreviousU));
            return(hatR);
        }
Exemplo n.º 7
0
        private double[] NewtonIterationsNewmark(double[] forceVector, int stepNumber, List <double> aConstants)
        {
            lambda = 1.0 / numberOfLoadSteps;
            //double[] incrementDf = VectorOperations.VectorScalarProductNew(forceVector, lambda);
            double[] solutionVector = new double[forceVector.Length];
            double[] deltaU         = new double[solutionVector.Length];
            double[] internalForcesTotalVector;
            double[] residual;
            double   residualNorm;

            double[] hatR;

            solutionVector = explicitSolution.Values.Last();

            Assembler.UpdateDisplacements(solutionVector);

            //Assembler.UpdateAccelerations(explicitAcceleration.Values.Last());
            hatR = CalculateHatRVectorNewmarkNL(stepNumber, aConstants, solutionVector);
            internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();
            residual = VectorOperations.VectorVectorSubtraction(hatR, internalForcesTotalVector);
            residual = VectorOperations.VectorVectorSubtraction(forceVector, Assembler.CreateTotalInternalForcesVector());
            int iteration = 0;

            Array.Clear(deltaU, 0, deltaU.Length);

            for (int i = 0; i < maxIterations; i++)
            {
                double[,] tangentMatrix = CalculateHatKMatrixNewmark(aConstants);
                deltaU         = LinearSolver.Solve(tangentMatrix, residual);
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                Assembler.UpdateDisplacements(solutionVector);
                //Assembler.UpdateAccelerations(CalculateAccelerations());
                hatR = CalculateHatRVectorNewmarkNL(stepNumber, aConstants, solutionVector);
                internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();
                residual     = VectorOperations.VectorVectorSubtraction(hatR, internalForcesTotalVector);
                residualNorm = VectorOperations.VectorNorm2(residual);
                if (residualNorm < tolerance)
                {
                    break;
                }
                iteration = iteration + 1;
            }
            //Console.WriteLine(iteration);
            if (iteration >= maxIterations)
            {
                Console.WriteLine("Newton-Raphson: Solution not converged at current iterations");
            }

            return(solutionVector);
        }
Exemplo n.º 8
0
        private double[] CalculateAccelerationNewmark(int step, List <double> aConstants)
        {
            double[] dUt      = explicitVelocity[step - 1];
            double[] ut       = explicitSolution[step - 1];
            double[] utplusDt = explicitSolution[step];
            double[] ddUt     = explicitAcceleration[step - 1];

            double[] part1 = VectorOperations.VectorScalarProductNew(
                VectorOperations.VectorVectorSubtraction(utplusDt, ut), aConstants[0]);
            double[] part2 = VectorOperations.VectorScalarProductNew(dUt, aConstants[2]);
            double[] part3 = VectorOperations.VectorScalarProductNew(ddUt, aConstants[3]);

            double[] ddUtplusDt = VectorOperations.VectorVectorSubtraction(part1,
                                                                           VectorOperations.VectorVectorAddition(part2, part3));
            return(ddUtplusDt);
        }
Exemplo n.º 9
0
        private double[] LoadControlledNR(double[] forceVector)
        {
            double[] incrementDf    = VectorOperations.VectorScalarProductNew(forceVector, lambda);
            double[] solutionVector = new double[forceVector.Length];
            double[] incrementalExternalForcesVector = new double[forceVector.Length];
            double[] tempSolutionVector = new double[solutionVector.Length];
            double[] deltaU             = new double[solutionVector.Length];
            double[] internalForcesTotalVector;
            double[] dU;
            double[] residual;
            double   residualNorm;

            for (int i = 0; i < numberOfLoadSteps; i++)
            {
                incrementalExternalForcesVector = VectorOperations.VectorVectorAddition(incrementalExternalForcesVector, incrementDf);
                base.UpdateDisplacements(solutionVector);
                internalForcesTotalVector = base.CreateTotalInternalForcesVector();
                double[,] stiffnessMatrix = base.CreateTotalStiffnessMatrix();
                dU             = linearSolver.Solve(stiffnessMatrix, incrementDf);
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, dU);
                residual       = VectorOperations.VectorVectorSubtraction(internalForcesTotalVector, incrementalExternalForcesVector);
                residualNorm   = VectorOperations.VectorNorm2(residual);
                int iteration = 0;
                Array.Clear(deltaU, 0, deltaU.Length);
                while (residualNorm > tolerance && iteration < maxIterations)
                {
                    stiffnessMatrix    = base.CreateTotalStiffnessMatrix();
                    deltaU             = VectorOperations.VectorVectorSubtraction(deltaU, linearSolver.Solve(stiffnessMatrix, residual));
                    tempSolutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                    base.UpdateDisplacements(tempSolutionVector);
                    internalForcesTotalVector = base.CreateTotalInternalForcesVector();
                    residual     = VectorOperations.VectorVectorSubtraction(internalForcesTotalVector, incrementalExternalForcesVector);
                    residualNorm = VectorOperations.VectorNorm2(residual);
                    iteration    = iteration + 1;
                }
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                if (iteration >= maxIterations)
                {
                    Console.WriteLine("Newton-Raphson: Solution not converged at current iterations");
                }
            }

            return(solutionVector);
        }
Exemplo n.º 10
0
        private double[] CalculateInitialAccelerationsNewmark() //Bathe page 771
        {
            if (CustomStiffnessMatrix != null)
            {
                return(InitialValues.InitialAccelerationVector);
            }
            int step = explicitSolution.Count - 1;

            Assembler.UpdateDisplacements(explicitSolution[step]);
            double[,] stiffness = Assembler.CreateTotalStiffnessMatrix();
            double[,] mass      = Assembler.CreateTotalMassMatrix();

            double[] Ku  = VectorOperations.MatrixVectorProduct(stiffness, explicitSolution[step]);
            double[] RHS = VectorOperations.VectorVectorSubtraction(ExternalForcesVector, Ku);

            double[] acceleration = LinearSolver.Solve(mass, RHS);

            return(acceleration);
        }
Exemplo n.º 11
0
        private double[] CalculateHatRVectorNewmarkNL(int i, List <double> aConstants, double[] previousIterationSolution)
        {
            double[,] TotalMassMatrix;
            double[,] TotalDampingMatrix;
            double[,] TotalStiffnessMatrix;
            if (CustomMassMatrix != null)
            {
                TotalMassMatrix      = CustomMassMatrix;
                TotalDampingMatrix   = CustomDampingMatrix;
                TotalStiffnessMatrix = CustomStiffnessMatrix;
            }
            else
            {
                TotalMassMatrix      = Assembler.CreateTotalMassMatrix();
                TotalDampingMatrix   = Assembler.CreateTotalDampingMatrix();
                TotalStiffnessMatrix = Assembler.CreateTotalStiffnessMatrix();
            }

            double[] currentU   = explicitSolution[i - 1];
            double[] currentdU  = explicitVelocity[i - 1];
            double[] currentddU = explicitAcceleration[i - 1];

            double[] a0U = VectorOperations.VectorScalarProductNew(
                VectorOperations.VectorVectorSubtraction(currentU, previousIterationSolution), aConstants[0]);
            double[] a2dU  = VectorOperations.VectorScalarProductNew(currentdU, aConstants[2]);
            double[] a3ddU = VectorOperations.VectorScalarProductNew(currentddU, aConstants[3]);
            double[] a1U   = VectorOperations.VectorScalarProductNew(currentU, aConstants[1]);
            double[] a4dU  = VectorOperations.VectorScalarProductNew(currentdU, aConstants[4]);
            double[] a5ddU = VectorOperations.VectorScalarProductNew(currentddU, aConstants[5]);

            double[] vectorSum1 = VectorOperations.VectorVectorAddition(a0U,
                                                                        VectorOperations.VectorVectorAddition(a2dU, a3ddU));
            double[] vectorSum2 = VectorOperations.VectorVectorAddition(a1U,
                                                                        VectorOperations.VectorVectorAddition(a4dU, a5ddU));

            double[] part1 = VectorOperations.MatrixVectorProduct(TotalMassMatrix, vectorSum1);
            double[] part2 = VectorOperations.MatrixVectorProduct(TotalDampingMatrix, vectorSum2);

            double[] hatR = VectorOperations.VectorVectorAddition(ExternalForcesVector,
                                                                  VectorOperations.VectorVectorAddition(part1, part2));
            return(hatR);
        }
Exemplo n.º 12
0
        private double[] CalculateHatRVectorNL(int i)
        {
            Assembler.UpdateDisplacements(explicitSolution[i - 1]);

            double[,] totalMassMatrix    = Assembler.CreateTotalMassMatrix();
            double[,] totalDampingMatrix = Assembler.CreateTotalDampingMatrix();
            double[,] a2M  = MatrixOperations.ScalarMatrixProductNew(a2, totalMassMatrix);
            double[,] a0M  = MatrixOperations.ScalarMatrixProductNew(a0, totalMassMatrix);
            double[,] a1C  = MatrixOperations.ScalarMatrixProductNew(-a1, totalDampingMatrix);
            double[,] hutM = MatrixOperations.MatrixAddition(a0M, a1C);

            double[] F            = Assembler.CreateTotalInternalForcesVector();
            double[] hatPreviousU = VectorOperations.MatrixVectorProduct(hutM, explicitSolution[i - 2]);
            double[] a2Mut        = VectorOperations.MatrixVectorProduct(a2M, explicitSolution[i - 1]);


            double[] hatR1     = VectorOperations.VectorVectorSubtraction(ExternalForcesVector, F);
            double[] hatR2     = VectorOperations.VectorVectorSubtraction(a2Mut, hatPreviousU);
            double[] hatRtotal = VectorOperations.VectorVectorAddition(hatR1, hatR2);
            return(hatRtotal);
        }
Exemplo n.º 13
0
        private double[] StartNewtonIterations(double[] forceVector)
        {
            lambda = 1.0 / numberOfLoadSteps;

            double[] solutionVector     = new double[forceVector.Length];
            double[] tempSolutionVector = new double[solutionVector.Length];
            double[] deltaU             = new double[solutionVector.Length];
            double[] internalForcesTotalVector;
            double[] dU;
            double[] residual;
            double   residualNorm;

            discretization.UpdateDisplacements(solutionVector);
            residual = VectorOperations.VectorVectorSubtraction(forceVector, discretization.CreateTotalInternalForcesVector());
            int iteration = 0;

            Array.Clear(deltaU, 0, deltaU.Length);
            for (int i = 0; i < MaxIterations; i++)
            {
                double[,] tangentMatrix = discretization.CreateTotalStiffnessMatrix();
                deltaU         = linearSolver.Solve(tangentMatrix, residual);
                solutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                discretization.UpdateDisplacements(solutionVector);

                internalForcesTotalVector = discretization.CreateTotalInternalForcesVector();
                residual     = VectorOperations.VectorVectorSubtraction(forceVector, internalForcesTotalVector);
                residualNorm = VectorOperations.VectorNorm2(residual);
                if (residualNorm < Tolerance)
                {
                    continue;
                }
                iteration = iteration + 1;
            }
            if (iteration >= MaxIterations)
            {
                Console.WriteLine("Newton-Raphson: Solution not converged at current iterations");
            }

            return(solutionVector);
        }
Exemplo n.º 14
0
        private double[] Project(double[] ksiVectorInitial)
        {
            int    maxIterations = 1000;
            double tol           = Math.Pow(10.0, -4.0);

            double[] deltaKsi = new double[2];
            double   norm     = new double();

            double[] ksiVector = ksiVectorInitial;
            double[] xUpdated  = xUpdatedVector();
            for (int i = 1; i <= maxIterations; i++)
            {
                double[] oldksiVector = ksiVector;
                Tuple <double[, ], double[, ], double[, ]> aMatrices = CalculatePositionMatrix(ksiVector[0], ksiVector[1]);
                List <double[]> dRho = SurfaceVectors(ksiVector[0], ksiVector[1]);
                double[]        f    = Calculate_f(dRho, aMatrices.Item1, xUpdated);
                double          e    = Calculate_e(aMatrices.Item1, xUpdated);//double e = Calculate_e(aMatrices.Item2, xUpdated);
                double[,] m = MetricTensor(dRho);
                double detm = MetricTensorDet(m);
                deltaKsi  = CalculateDeltaKsi(detm, m, f, e);
                ksiVector = VectorOperations.VectorVectorAddition(ksiVector, deltaKsi);//Iterations for the CPP?
                norm      = VectorOperations.VectorNorm2(VectorOperations.VectorVectorSubtraction(ksiVector, oldksiVector));
                if (norm <= tol)
                {
                    break;
                }
            }
            if (norm > tol)
            {
                throw new Exception("CPP not found in current iterations");
            }
            else
            {
                return(ksiVector);
            }
        }
Exemplo n.º 15
0
        private double[] NewtonIterationsExplicit(int timeStep, double[] forceVector, double[,] tangentMatrix)
        {
            //lambda = 1.0 / numberOfLoadSteps;
            //double[] incrementDf = VectorOperations.VectorScalarProductNew(forceVector, lambda);
            double[] solutionVector = new double[forceVector.Length];
            double[] deltaU         = new double[solutionVector.Length];
            //double[] internalForcesTotalVector;
            double[] residual;
            double   residualNorm;

            double[] hatRPrevious;
            double[] hatRNext;

            solutionVector = explicitSolution.Values.Last();

            Assembler.UpdateDisplacements(solutionVector);

            Assembler.UpdateAccelerations(explicitAcceleration.Values.Last());
            hatRPrevious = CalculateHatRVectorNL(timeStep);
            hatRNext     = hatRPrevious;
            //internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();
            //residual = VectorOperations.VectorVectorSubtraction(hatR, internalForcesTotalVector);
            residual = hatRPrevious;
            int iteration = 0;

            Array.Clear(deltaU, 0, deltaU.Length);

            for (int i = 0; i < maxIterations; i++)
            {
                if (i == 0)
                {
                    //deltaU = LinearSolver.Solve(tangentMatrix, residual);
                    //solutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                    solutionVector = LinearSolver.Solve(tangentMatrix, residual);
                    Assembler.UpdateDisplacements(solutionVector);
                    //Assembler.UpdateAccelerations(CalculateAccelerations());
                    hatRNext = CalculateHatRVectorNL(timeStep);
                    //internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();
                    residual     = VectorOperations.VectorVectorSubtraction(hatRNext, hatRPrevious);
                    residualNorm = VectorOperations.VectorNorm2(residual);
                    if (residualNorm < tolerance)
                    {
                        break;
                    }
                    iteration    = iteration + 1;
                    hatRPrevious = hatRNext;
                }
                else
                {
                    deltaU         = LinearSolver.Solve(tangentMatrix, residual);
                    solutionVector = VectorOperations.VectorVectorAddition(solutionVector, deltaU);
                    //solutionVector = LinearSolver.Solve(tangentMatrix, residual);
                    Assembler.UpdateDisplacements(solutionVector);
                    //Assembler.UpdateAccelerations(CalculateAccelerations());
                    hatRNext = CalculateHatRVectorNL(timeStep);
                    //internalForcesTotalVector = Assembler.CreateTotalInternalForcesVector();
                    residual     = VectorOperations.VectorVectorSubtraction(hatRNext, hatRPrevious);
                    residualNorm = VectorOperations.VectorNorm2(residual);
                    if (residualNorm < tolerance)
                    {
                        break;
                    }
                    iteration    = iteration + 1;
                    hatRPrevious = hatRNext;
                }
            }
            //Console.WriteLine(iteration);
            if (iteration >= maxIterations)
            {
                Console.WriteLine("Newton-Raphson: Solution not converged at current iterations");
            }

            return(solutionVector);
        }