my code is showing not enough input argument error how to resolve

clear all; close all; clc;
dx=0.01;
L=20;
x=-L/2:dx:L/2-dx;
f=0*x;
f=sech(x);
plot(x,f)

dt=0.025;  % integral in time in increments of 0.025
for k =1:100
    t=k*dt;
    [t,y]=ode45(@(t,y)rhsNEW(t,y,L),[0 dt],f);
    % we are assuming ode 45 is taking a lot of little steps and we want to
    % to take the last step
    f(:)=y(end,:);
    plot(x,real(f))
    axis([-10 10 -1.5 1.5])
    pause(0.1)
end

function is -

function dout=rhsNEW(t,u,L)
pi=3.14;
Nx =length(u);
uhat=fft(u);
kap=(2*pi/L)*[-Nx/2:Nx/2-1];
kap=fftshift(kap');
duhat=1i*kap.*uhat;
du=ifft(duhat);
duout=-du;

Answer 1

[Walter Roberson]

I tested your code and do not get that error. What I get is

Output argument "dout" (and maybe others) not assigned during call to "rhsNEW".

which is correct, as you assign to a variable named duout but not to dout.

When I change that variable name the code seems to work.

[asim asrar]

Dear Walter Roberson, Thanks for the response, i have changed the variable duout to dout , but it is still showing the error of not enough input argument , what changes should i need to make in my code

clear all; close all; clc; dx=0.01; L=20; x=-L/2:dx:L/2-dx; f=0*x; f=sech(x); plot(x,f)

dt=0.025; % integral in time in increments of 0.025 for k =1:100 t=k*dt; [t,y]=ode45(@(t,y)rhsNEW(t,y,L),[0 dt],f); % we are assuming ode 45 is taking a lot of little steps and we want to % to take the last step f(:)=y(end,:); plot(x,real(f)) axis([-10 10 -1.5 1.5]) pause(0.1) end

function dout=rhsNEW(t,u,L) pi=3.14; Nx =length(u); uhat=fft(u); kap=(2*pi/L)*[-Nx/2:Nx/2-1]; kap=fftshift(kap); duhat=1i*kap.*uhat; du=ifft(duhat); dout=-du;

[asim asrar]

sorry there is no error now , thanks a-lot for the help