using t in the ode function

hello i am using the function of ode 45 but if for exmpale I i want to give value by the change of t,for exmaple i have this code :

function [ zigzag_simulation] = find_zigzag( t,x)

global R R1 C C1 L1 L2  U Duty_cycle alpha R_C R2 R_C1 V_diode R_diode

global A_T B_T C_T D_T  V_desire f tspan

global A_a A_b B_a B_b

t_off=((alpha+1)*(f))^(-1);

   ratio=rem(t,(1/f));

end

is it posbiile to use t ? becouse i have an error

Answer 1

[Walter Roberson]

It is legal to use t in the ode function. However, you have used rem() in your calculations, which makes your output discontinuous. The ode function must be continuous to at least one more derivative than you use yourself or else MATLAB will detect the discontinuity. If the ode function is not continuous to at least one derivative further than that then ode45 will give the wrong answer but might not detect the discontinuity.

[tomer polsky]

so how can i solve this problem ? I am sorry for my english it is not my first language

[Walter Roberson]

We do not know how to fix the code. You have no comments in the code, and you did not give the equations to be solve.

Also, your function is defined as

function [ zigzag_simulation] = find_zigzag( t,x)

but you do not assign anything to zigzag_simulation.