Distributed-computing method for computing a metric representative of a difference between two data

A distributed-computing method for computing a metric f(X,Y) representative of a difference between a datum X having n bits (x1, . . . , xn) and a datum Y, the metric f(X,Y) taking the form:

• f(X,Y)=fX(X)+Σi=1nfi(xi,Y)+fY(Y)
• where fX is a function depending solely on the datum X, fY is a function depending solely on the datum Y, and for any i ranging from 1 to n, fi is a predefined function,
• the method being implemented by a system including m+1 distinct devices (D1, . . . , Dm+1) having respective indices ranging from 1 to m+1, with m≥2, the method comprising:
• for any j ranging from 1 to m, computing at least one intermediate datum by way of the device of index j (Dj), each intermediate datum depending on the datum X and on the datum Y, and transmitting to the device of index m+1 (Dm+1) at least one result including or depending on each intermediate datum;
• and
• determining, by way of the device of index m+1 (Dm+1), the metric f(X,Y), the determining including summing each result to obtain a value equal to Σi=1nfi(xi,Y) or a value equal to Σi=1nfi(xi,Y)+fY(Y).