Les pionniers des CAS

Ne croyez pas que le calcul formel sur ordinateur ait été inventé par et pour des mathématiciens. Les divers logiciels ont en fait deux origines distinctes. D'une part, les informaticiens, alors aux débuts de l'intelligence artificielle, cherchaient à réaliser le programme visionnaire d'Ada Lovelace. D'autre part les physiciens se heurtaient à des calculs de plus en plus sophistiqués qu'il devenait quasiment impossible de réaliser à la main. Voici ce que dit l'un d'eux, A.C. Hearn, créateur du logiciel REDUCE⁴.

[In 1963], I began writing a program that would be distributed within a few years as REDUCE. It all began while I was a postdoc in Theoretical Physics at Stanford, working with Feynman diagrams which were becoming increasingly difficult to calculate by hand. I therefore wondered if such calculations could be done by computer.

A new professor in the Stanford Computer Department, John McCarthy, gave a talk in the Physics Department proposing his computer language Lisp as the basis for non-numerical calculations in physics. I was out of town, and therefore missed this talk. However, a colleague, knowing my interest in automating Feynman diagram calculations, suggested I talk to McCarthy about his work. To cut a long story short, McCarthy convinced me that his language would be a suitable basis for such calculations. Part of his efforts to convince me included the offer of free access to a new computer he was acquiring. In those days, getting computer access was not a trivial thing. Computer at that time were expensive with limited access, so such an offer was irresistible! Thus began my work with symbolic computation.

Eh oui, les «Computer Algebra Systems» (CAS) sont nés il y a plus d'un demi-siècle, au temps où l'accès à un ordinateur «n'était pas une chose triviale». Si, si, l'électricité existait déjà...