MATLAB License Keys when using functions from a toolbox

I read in https://www.mathworks.com/matlabcentral/answers/99343-how-do-i-release-or-return-a-toolbox-license-key-back-to-the-pool-of-available-keys-without-restarti that when a function from a toolbox is used, a licesnse key must be checked out.

My question is that if it must checkout a key to use the function, does it also then return the key after the function call is done? Say a for loop would run 10 times and only uses the function, then does the key get check out and then checked back in 10 times as well? Or does it only get checked out once until I exit MATLAB.

Answer 1

[Mann Baidi]

Hi Sean,

I understand that you would like to confirm whether the license key gets returned to the pool after the function call of the toolbox is completed.

I am not aware whether it will return to the pool or not, but you can check the license usage of the pool. If you have the license server, you can refer to the following MATLAB answer to track the license usage.

https://www.mathworks.com/matlabcentral/answers/102546-how-do-i-monitor-the-usage-of-license-keys-for-matlab-and-toolboxes

Else, if you do not have the license erver you can check the following MATLAB answer for monitoring the license usage.

https://www.mathworks.com/matlabcentral/answers/102830-is-there-a-way-for-licenses-to-be-monitored-from-the-client-machine-instead-of-the-server

You can then check if the license is being checked out for every function or for the MATLAB session.

Hope this help in resolving your query!

Answer 2

[Image Analyst]

The license is not checked out and back in again after every call. I'm not sure when they're checked back in : after a while, or after you exit MATLAB. But once I was teaching a MATLAB programming class and a bunch of people in my class were using a "pooled" license. There were different numbers of licenses for MATLAB, and each toolbox. So sometime people in my class couldn't use MATLAB or a function we were trying to use. And people out there in the company (not in my class) also called me and were upset that my class had used a bunch of licenses and because of that they couldn't do their work. But I know the license is not checked in instantaneously after the function exits - I just don't know if there is some time, or if it's when you exit MATLAB. I know we had to call some people and ask them if they were still using MATLAB. They said no, that they had just used it in the morning for a few minutes and then it was just sitting idle, but still running for a long time. They exited MATLAB and then we could use it again. So I don't think it turns it back in after a while - I think it only gets turned in if you exit MATLAB, though I could be wrong.

By the way, the license checkout happens automatically - you don't have to manually check in or out any licenses.