At the 1940s Manhattan project, back when computer meant a job: "person who computes mathematical statements", major advancements were made in the integration of hyperbolic PDEs, by substituting electro-mechanical and then vacuum-tube machines to do the job. You know, those hard-wired vacuum tube monsters like ENIAC.
You could argue that the First useful thing electronic computers did was integration...
You could argue that the First useful thing electronic computers did was integration...
https://www.tandfonline.com/doi/full/10.1080/00295450.2021.1...