ODE_2DSSM_CARTESIAN_FIXROM_DFDP

Contents

function [J] = ode_2DSSM_cartesian_fixROM_DFDP(t, x, p, data,contribNonAuto)
        

This function computes the jacobian of reduced dynamics in its time dependent normal form in cartesian coordinates for a 2D SSM with respect to the parameters omega and epsilon. This function is not vectorised as of now. It assumes weak dependence of the non-autonomous RD coefficients upon changing omega and thus does not recompute the ROM when omega is changed.

[y] = ODE_2DSSM_CARTESIAN_FIXROM_DFDP(t, x, p, data,obj)

See also: ODE_2DSSM_CARTESIAN_FIXROM_DFDX, ODE_2DSSM_CARTESIAN_FIXROM

order = data.order;
om = p(1,:);

% Autonomous part

J = aut_J_dp();


% Nonautonomous part
if contribNonAuto

    J = nonaut_J_dp(t,x,p,data.S,J);

else
    J = lead_nonaut_J_dp(t,p,data.S,J);
end
        

end



function [J] = aut_J_dp()
% Autonomous part of the jacobian
% no dependence on omega and epsilon
J = zeros(2);
end


function [J] = nonaut_J_dp(t,x,p,S,J)
        

% Nonautonomous part of the reduced dynamics including leading order
J_11 = J(1,1); %dx(1,:)dotdOmega
J_21 = J(2,1); %dx(2,:)dotdOmega
J_12 = J(1,2); %dx(1,:)dotdepsilon
J_22 = J(2,2); %dx(2,:)dotdepsilon

%parametrisation coordinates
q1 = x(1,:) + 1i * x(2,:);
q2 = x(1,:) - 1i * x(2,:); %conjugate of q1

om  = p(1,:);
eps = p(2,:);
        

Leading order

Reduced Dynamics Coefficients

[~,~,s] = find(S(1).R(1).coeffs(1,:));
if ~isempty(s)
exp_kap = exp(1i* S(1).kappa * om.*t);

J_11 = J_11 + eps.*(real(1i*S(1).kappa.*t.* s .* exp_kap));
J_21 = J_21 + eps.*(imag(1i*S(1).kappa.*t.*s .* exp_kap));
J_12 = J_12 + (real(s .* exp_kap));
J_22 = J_22 + (imag(s .* exp_kap));
end
        

Higher orders

{

num_kappa = numel(S);
for i = 1:num_kappa %each harmonic
    kappa = S(i).kappa;
    exp_kap = exp(1i* kappa * om.*t);
    for k = 1:(numel(S(i).R)-1) %every spatial expansion order
        Sk = S(i).R(k+1); %order k coefficients

        [~,col,s] = find(Sk.coeffs(1,:));

        if any(col)
            exp_k = Sk.ind(col,:); %exponent of spatial component
            run_idx = 1;
            for s_j = s

                % Spatial contribution
                m1 = exp_k(run_idx,1);
                m2 = exp_k(run_idx,2);
                spatial_part = q1.^m1.*q2.^m2;

                % Frequency contribution with coeffs
                freq_part    = s_j*exp_kap;
                i_kappa_t    = 1i*kappa*t; % derivative coefficient form exp_kap

                J_11 = J_11 + eps.*(real(spatial_part .* i_kappa_t.* freq_part));  %dx(1,:)dotdOmega
                J_21 = J_21 + eps.*(imag(spatial_part .* i_kappa_t.* freq_part));  %dx(2,:)dotdOmega

                J_12 = J_12 +      real((spatial_part .* freq_part)); %dx(1,:)dotdepsilon
                J_22 = J_22 +      imag((spatial_part .* freq_part)); %dx(2,:)dotdepsilon

                run_idx = run_idx+1;
            end
        end

        %{
        % Sensitivity coefficients
        DSk = DS(i).R(k+1); %order k coefficients
        [~,dcol,ds] = find(DSk.coeffs(1,:));

        if any(dcol)
            exp_k = DSk.ind(dcol,:); %exponent of spatial component
            run_idx = 1;
            for ds_j = ds
                % Spatial contribution
                m1 = exp_k(run_idx,1);
                m2 = exp_k(run_idx,2);
                spatial_part = q1.^m1.*q2.^m2;

                % Frequency contribution with coeffs
                freq_der     = ds_j *exp_kap;

                % Derivatives of the coefficients
                J_11 = J_11 + eps.*(real(spatial_part .* freq_der));  %dx(1,:)dotdOmega
                J_21 = J_21 + eps.*(imag(spatial_part .* freq_der));  %dx(2,:)dotdOmega

                run_idx = run_idx+1;
            end
        end
        %}
    end
end
%}
J = [ J_11, J_12 ...
    ; J_21, J_22];
        

end


function [J] = lead_nonaut_J_dp(t,p,S,J)
        

% Nonautonomous part of the reduced dynamics including only leading order
J_11 = J(1,1); %dx(1,:)dotdOmega
J_21 = J(2,1); %dx(2,:)dotdOmega
J_12 = J(1,2); %dx(1,:)dotdepsilon
J_22 = J(2,2); %dx(2,:)dotdepsilon


om  = p(1,:);
eps = p(2,:);
        

Leading order

Reduced Dynamics Coefficients

[~,~,s] = find(S(1).R(1).coeffs(1,:));
if ~isempty(s)
exp_kap = exp(1i* S(1).kappa * om.*t);

J_11 = J_11 + eps.*(real(1i*S(1).kappa.*t.* s .* exp_kap));
J_21 = J_21 + eps.*(imag(1i*S(1).kappa.*t.*s .* exp_kap));
J_12 = J_12 + (real(s .* exp_kap));
J_22 = J_22 + (imag(s .* exp_kap));
end

J = [ J_11, J_12 ...
    ; J_21, J_22];
        

end
        

Published with MATLAB® R2023a