how to correct ''Function definitions are not permitted in this context.''

Function definitions are not permitted in this context.

a = 0.5;
B = 0.6;
k = 1; 
[t, x] = ode45(@Ray, [0 30],[ 0 0.1], [], a, B, k); 
plot(x(:,1), x(:,2), 'k-') 
function d = Ray(t, y, a, B, k)
d=[y(2);-k*y(1)+a*y(2)-B*y(2^3];

Answer 1

[Image Analyst]

You can't have a script and a function inside the same m-file. You can have two functions and they don't need to be nested . For example if your m-file is called test.m, you could have test() and Ray() both inside test.m like this:

function test()
a = 0.5;
B = 0.6;
k = 1; 
[t, x] = ode45(@Ray, [0 30],[ 0 0.1], [], a, B, k); 
plot(x(:,1), x(:,2), 'k-') 

function d = Ray(t, y, a, B, k)
d=[y(2);-k*y(1)+a*y(2)-B*y(2^3];

[Star Strider]

Your illustration seems to match exactly the definition of Nested Functions (absent the ‘end’ statements).

[Image Analyst]

I believe they're not nested. Even if you put an end at the end of each one they're still not nested. Ray would not be nested inside test unless the end for test() occurred after Ray(), because in that case Ray would lie completely inside (nested) of test.

[John D'Errico]

Star - This is NOT a nested function. It is a sub-function, a different animal. A nested function can see the workspace of the parent function. A sub-function cannot, although it resides in the same file. There is a difference, and it is essentially controlled by proper placement of appropriate end statements as Image has stated.

Answer 2

[sarvesh aundhkar]

function test() a = 0.5; B = 0.6; k = 1; [t, x] = ode45(@Ray, [0 30],[ 0 0.1], [], a, B, k); plot(x(:,1), x(:,2), 'k-') function d = Ray(t, y, a, B, k) d=[y(2);-k*y(1)+a*y(2)-B*y(2^3];