1. A method for clustering data or objects taking the form of an array S, each of the elements of said array S corresponding to a value of similarity s ij existing between said data or objects, said method being implemented within a computer linked with a database containing the data or objects to be clustered comprising a work memory, and a processor, the method comprising: 1) determining a number k of classes of objects in the following manner: take one of the data or objects, O i , which has the fewest possible similarities s ij with the other data or objects, for which the sum of the components ∑ i ′ = 1 n ⁢ s ii ′ of a profile for O i is the smallest, Place the individual O i in a first class C 1 , Consider the remaining data or objects different from O i and take from among them a second object O j , for which the sum of the components of a profile for O j is the smallest out of the remaining objects, if a relationship l jC 1 computed between the second object O j with the previous class C 1 consisting of a single individual is negative, then create a new class C 2 and place the second object O j in the new class C 2 , otherwise if this relationship is positive, place the object O j in the class C 1 , repeat until all the data or objects O j belong to a class of index k, on completion of this first step the method has a set of κ classes, 2) for each of the κ classes found in step 1), determine the value of the relationships between a class C k and the other classes C k′ such that k′ is different from k, if all the relationships determined l C k C k′ are negative, then do not merge the class C k with another class, Otherwise, merge the class considered C k with the class C k′ with which C k has the strongest relationship, the highest value l C k C k′ , add this value to the criterion C ⁡ ( X ) = ( ∑ k = 1 κ ⁢ l C k ⁢ C k ) + l C k ⁢ C k ′ until stability of this criterion is obtained, on completion of step 2), the method has L classes with L≦κ, 3) determining, for each object of each class C l with l≦L one by one, a value of a relationship l iC m of the object with each of the classes C j other than the class of index k into which the object was classed in step, 1) if a value of a relationship l iC m with the class of index m is greater than the value of the relationship l iC k then transfer the object from the class of index k to the new class of index m, this is continued until all the values of the relationships l iC k are negative.