linear ordinary differential equations in matlab

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TT
TT 2015-6-14
编辑： Jan 2015-6-14
Dear all, Can anybody debug my code? I want to find an answer for a differential equation. Let's see the first code. It works. However, for the second code, MATLAB gives an error "Not enough inputs to inline function.".
Function:
function [xvalues, yvalues] = eulerss(f,x0,xn,y0,n)
%EULER: MATLAB function M-file that solve the
%ODE y’=f, y(x0)=y0 on [x0,y0] using a partition
%with n equally spaced subintervals
dx = (xn-x0)/n;
x(1) = x0;
y(1) = y0;
for k=1:n
x(k+1)=x(k) + dx;
y(k+1)= y(k) + f(x(k),y(k))*dx;
end
xvalues = x';
yvalues = y';
Implementation:
f=inline('sin(x*y)')
[x,y]=eulerss(f,0,1,pi,10)
plot(x,y)
second code... Function:
function [tvalues, zvalues] = eulers(F,t0,tn,z0,n)
%EULER: MATLAB function M-file that solve the
%ODE z'=F, z(t0)=0 on [t0,z0] using a partition
%with n equally spaced subintervals
dt=(tn-t0)/n;
t(1)=t0;
z(1)=z0;
for k=1:n
t(k+1)=t(k)+dt;
z(k+1)=z(k)+F(t(k),z(k))*dt;
end
tvalues=t
zvalues=z
implementation:
clc
clear all
a=1;
b=1;
c=0.1;
x=0.001;
F=inline('(b/c)*(x-z)')
[t,z]=eulers(F,0,1,0,10)
plot(t,z)

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回答（1 个）

Jan
Jan 2015-6-14
编辑：Jan 2015-6-14
inline functions are an outdated method to define functions. Use the modern method of an anonymous function or write an own function for the formula.
See also: http://www.mathworks.com/matlabcentral/answers/1971

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