www.gusucode.com > symbolic 源码程序 matlab案例代码 > symbolic/ConvertDAESystemToMassMatrixFormExample.m
%% Convert DAE System to Mass Matrix Form %% 1 syms x1(t) x2(t) f(t, x1, x2) r m eqs = [m*x2(t)*diff(x1(t), t) + m*t*diff(x2(t), t) == f(t, x1(t), x2(t)),... x1(t)^2 + x2(t)^2 == r^2]; vars = [x1(t), x2(t)]; %% 2 [M, F] = massMatrixForm(eqs, vars) %% 3 syms Y1 Y2 M = subs(M, [vars, m, r, f], [Y1, Y2, 100, 1, @(t,x1,x2) t + x1*x2]); F = subs(F, [vars, m, r, f], [Y1, Y2, 100, 1, @(t,x1,x2) t + x1*x2]); %% 4 MM = matlabFunction(M, 'vars', {t, [Y1; Y2]}); FF = matlabFunction(F, 'vars', {t, [Y1; Y2]}); %% 5 opt = odeset('Mass', MM, 'InitialSlope', [0.005;0]); ode15s(FF, [0,1], [0.5; 0.5*sqrt(3)], opt)