Replies to message #7,418

🔎 If you see an alert for analytics.usips.org, this is a self-hosted system I am running as a test. It is GDPR compliant and collects no invasive information.

I mean it in the sense of defining an operator Δ whereby for a sequence or function s(n), Δs = s(n+1) - s(n). It's essentially the derivative for...