Fix lazy rand affine

[function2-llx]

Fixes #6773.

Description

Call rand_affine_grid() once before call rand_affine_grid.get_transformation_matrix(), since its documented as "Get the most recently applied transformation matrix", or the .affine attribute will not be set.
Also, set randomize=False here since randomization if performed in the beginning of the function.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.

[function2-llx]

very sad, find this bug after training the model for 5 days

[ericspod]

@atbenmurray could you please have a look (I'm away still)? Thanks!

[atbenmurray]

Hi there @function2-llx , I'm sorry you've had a problem with this. I'll take a look at the proposed fix.

[function2-llx]

Thank you for your concern, @atbenmurray. I understand that this is an open-source project and issues are part of the process. Let's continue to work together to improve this project!

[atbenmurray]

Please forgive the delay. I've been looking into the code this morning. I think we might want to go a little further than the current PR, but I'll make suggestions in the review once I've come to a conclusion on that.

[atbenmurray]

@function2-llx Ok, I had a look at a limited refactor of RandAffine and the classes that it uses, but I think it isn't possible to make tweaks without making a larger refactor. As such, I think we should go ahead with the change that you are proposing.

Do you want to write some unit tests to cover the change to RandAffine? We certainly need additional tests to cover this.

[function2-llx]

@atbenmurray Hi, I'd like to help, but I have to rush my conference submission recently (Due on Aug. 15th), so I'm afraid that this PR is the most I can help recently. I can help more after the submission is finished.

[atbenmurray]

@function2-llx Don't worry about it. It has been a very useful spot! I'll write up some additional unit tests to go with it.

[wyli]

/build

[wyli]

integration verified, please feel free to create follow up PRs, thanks