Jacobian function not found

Hello to all,

I have to use the "jacobian" function in Matlab. I have the Symbolic toolbox installed, but upon running jacobian(a, b), the prompt tells me :

??? Undefined function or variable 'jacobian'.

     What should I do?

Best regards,
 Jean

Answer 1

[Wayne King]

If you enter

>>ver

Do you see an entry for the Symbolic Toolbox?

If you enter:

license('test','symbolic_toolbox')

Do you get a 1 back? You may think you installed it, but perhaps something went wrong.

[Jean]

Hello Wayne,

the license test outputs zero, although the people in my department told me we have full matlab and symulink. I can actually see in the toolbox tab the "Symbolic Math" entry, but I do not understand why I cannot use this function.

[Walter Roberson]

If the license test outputs 0 then you either do not have the toolbox installed or you do not have a license for it. Sometimes the situation is that it is installed but the version installed does not match the MATLAB version.

If you use the command

ver

then you should be able to see the list of installed software and the version numbers.

One situation that crops up from time to time is that people install everything that comes with the installation CD, and have access to those functions during the demo period, but then when an actual license is installed, lose access to the additional toolboxes because no license was purchased for the toolboxes.

[Karen]

I do have the same problem with 2011a, jacobian is unknown even though my check for the toolbox resulted in "1"

Any suggestions?

[Walter Roberson]

What error message do you get, Karen?

What does

which -all jacobian

report ?

[Karen]

this is what I get:

>> jacobian

??? Undefined function or variable 'jacobian'.

>> license('test','symbolic_toolbox')

ans =

1

[Karen]

and here is what your request got me:

which -all jacobian

/Applications/MATLAB_R2011a.app/toolbox/symbolic/symbolic/@sym/jacobian.m % sym method

[Walter Roberson]

jacobian is a method of the symbolic class, so you have to invoke it with a symbolic argument for it to be located.

For example,

jacobian(sym('x^2+3*x*y-y^3'))

[Karen]

got it :) Thanks!

Answer 2

[Walter Roberson]

Which version are you using? I trace the function back at least as far as R14