Confusion, matlab, ode45 variables.

  • Thread starter Smiles302
  • Start date
  • #1
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Homework Statement



I am very confused over how matlab knows which variables are changeable variables in ode45.


Homework Equations

//

The Attempt at a Solution



My input is p

Earlier have defined;
a = 1;
k = 1;
w = 1/3;

Then I want to figure out adot and adoubledot from these.

adot = (a)*(p - k/a)^(-1/2);

adoubledot = (a/2)*(p + 3*w*p);

Suddenly realised that I have no idea why matlab would let "a" change but not let "p" and "k" change...

Is there a way to tell matlab that one of the variables is changing in time and the others aren't?
 

Answers and Replies

  • #2
27
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Nobody? =( Does my question make sense?
 
  • #3
jhae2.718
Gold Member
1,161
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I'm not sure exactly what you're asking. For ode45 you need to define a function. Ode45 uses the function definition for variables. (I think you need to have only one variable For ode45, so if you have more than one you can use a column vector.)
 

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