function p = initializeSecondPartialDerivative(p)%initializeSecondPartialDerivative - initializes the data structure holding%  the second partial derivative along all quanties defined in the vector%  mapping%% Nonlinear Filtering Toolbox version 2.0-rc4% Copyright (c) 1995 - 2007 NFT developement Team,%              Department of Cybernetics,%              University of West Bohemia in Pilsennvars = p.nvar;                          % get the number of the variablesif isempty(p.secondDerivative)    % create symbolic function form the string describing the multivariate    % vector mapping    f = sym(p.nffun);    % prepare symbolic variables from the list of all quantities elements    parameters = p.parameters;           % get the list of variables    symvars = sym(zeros(1,nvars));       % prealocate array of symbolic variables    for i = 1:nvars        symvars(i) = sym(parameters{i});    end    % determine the first differentiate of the function along all the    % symbolic variables    J = jacobian(f, symvars);    % determine Hessian matrix and create its string representation    cellDimension  = (p.nu+p.nx+p.nxi);  % dimesion of the cell array    % holding the second partial    % derivatives    secondPartialDerivatives = cell(cellDimension,cellDimension);    %create the cell array    % determine the MATLAB release number    release_number = str2num(version('-release'));    % determine Hessian matrices of each row of multivariate vector mapping    % and create their string representation    for i=1:nvars        %===============================================================        % create cell of strings describing Hessian matrices containing        % second partial derivatives of the multivariate vector mappings        % --------------------------------------------------------------        for j = 1:nvars            tmpPartialDerivative = jacobian(J(:,j),symvars(i));            % --------------------------------------------------------------            % it is necesary to remove prefixed description and convert            % commas to semicolons            % --------------------------------------------------------------            if ( isempty(release_number) || release_number>13 )                secondPartialDerivatives{i,j} = strrep(char(tmpPartialDerivative),'matrix','');            else                secondPartialDerivatives{i,j} = strrep(char(tmpPartialDerivative),'array','');            end            secondPartialDerivatives{i,j} = strrep(secondPartialDerivatives{i,j},'],','];');            %=============================================================        end    end    p.secondDerivative = secondPartialDerivatives;end