08-Jan-2022 10:33:36 tough_ode_test(): MATLAB/Octave version 9.8.0.1380330 (R2020a) Update 2 Solve the tough ODE. Parameter values: t0 = 0 y0 = (1,1,1,1) tstop = 3 tough_ode23(): Test tough_ode using ode23. [Warning: Failure at t=2.002174e-01. Unable to meet integration tolerances without reducing the step size below the smallest value allowed (4.440892e-16) at time t.] [> In ode23 (line 299) In tough_ode23 (line 28) In tough_ode_test (line 35) In run (line 91)] Number of variable steps = 71 Graphics saved in "tough_ode23_y1.png" Graphics saved in "tough_ode23_y2.png" Graphics saved in "tough_ode23_y3.png" Graphics saved in "tough_ode23_y4.png" tough_ode45(): Test tough_ode using ode45. Number of variable steps = 165 [Warning: Imaginary parts of complex X and/or Y arguments ignored.] [> In tough_ode45 (line 41) In tough_ode_test (line 37) In run (line 91)] Graphics saved in "tough_ode45_y1.png" [Warning: Imaginary parts of complex X and/or Y arguments ignored.] [> In tough_ode45 (line 56) In tough_ode_test (line 37) In run (line 91)] Graphics saved in "tough_ode45_y2.png" [Warning: Imaginary parts of complex X and/or Y arguments ignored.] [> In tough_ode45 (line 71) In tough_ode_test (line 37) In run (line 91)] Graphics saved in "tough_ode45_y3.png" [Warning: Imaginary parts of complex X and/or Y arguments ignored.] [> In tough_ode45 (line 86) In tough_ode_test (line 37) In run (line 91)] Graphics saved in "tough_ode45_y4.png" tough_midpoint: Test tough_ode using midpoint. Number of equal steps = 200000 Graphics saved in "tough_midpoint_y1.png" Graphics saved in "tough_midpoint_y2.png" Graphics saved in "tough_midpoint_y3.png" Graphics saved in "tough_midpoint_y4.png" tough_ode_test: Normal end of execution. 08-Jan-2022 10:35:24