Here's what happened: My phone started acting up. The lock button turned into a 'maybe turn the phone off' button. The unlock button turned into a 'maybe turn the phone off, or open the camera?' button. I impulse-purchased a new phone, and the old one magically fixed itself. New phone …

Background: I am running python with Theano on a GPU, and I care about speed. Scenario: I have a largeish matrix (C) which is stored as a shared variable, and I need to update a subset of the rows (modified_rows) by some other matrix (C_delta). What should I do? Initialising …