Luis Martinez is an iOS software developer with a reputation for releasing very good drumming apps in various styles. His latest is Jazz Drummer. His apps allow one to quickly set a groove, set variations and select a kit. About a year ago he released iBassist which gives similar capabilities for generating bass lines. And, amazingly, it interacts with his drum apps. These apps are for jamming, not trying to recreate a recording.

A gentleman named Doug Woods is much better than I at making demonstration videos.