I think they refer to Gradient Descent: https://en.wikipedia.org/wiki/Gradient_descent
Gradient descent uses the gradient, but is itself not the gradient.
The gradient itself is just the vector of partial derivatives with respect to each parameter.
Gradient descent is just following the gradient "downwards" towards a minima.
The article even describes it pretty well in non-mathematical terms.
> the gradient of the distribution (think of it as the slope of the high-dimensional surface).
I always hear devs say they never use calculus but I suspect it's because you can't use what you don't understand.
Yes, we do, like a decade ago at school when we were forced to learn it. Then the knowledge atrophies unless you're actively using it in real life.
The majority of engineers I know, including myself, work on some form of web services, mobile apps or FOTM UI frameworks, and you don't need calculus to style a progress bar or query a database
Could be a handy thing to have if, for example, you were designing some progress animation...
Any self-respecting CS theorist would tell you that accurate progress bars are generally impossible to make because that would reduce to some version of the halting problem; and any self-respecting software engineer would tell you that even in the simple cases where the halting problem is not a problem (eg. simple copying of files), in practice many things outside of the software's control could stall the progress.
Even if you could get an accurate progress value, you don't need a "gradient" to animate it. Just update the bar with the current value as a percentage at 60FPS and you're already done. (Progress bars generally ask the programmer to supply the current progress value, not a stream of progress rates in real time) If you tried to predict the progress "gradient" past the present point, you'd end up having to "lie" (more progress than actual) or have the progress bar jump back when it turns out the actual progress was slower than predicted.
If all you had was a hammer, everything looks like a nail. That almost always applies for those enamored with advanced maths.
I've seen a lot of cases where progress bars actually jump backwards because these predictions fail, whether it be games or applications, which feels like the universe is making fun of your existence when it happens.
Sometimes it feels like a 'this action is not stuck' indicator would be more appropriate.