EN
Given a module M over an algebra Λ and a complete set 𝓧 of pairwise nonisomorphic indecomposable Λ-modules, the problem of determining the vector $m(M) = (m_X)_{X∈ 𝓧} ∈ ℕ ^{𝓧}$ such that $M ≅ ⨁ _{X∈ 𝓧} X^{m_X}$ is studied. A general method of finding the vectors m(M) is presented (Corollary 2.1, Theorem 2.2 and Corollary 2.3). It is discussed and applied in practice for two classes of algebras: string algebras of finite representation type and hereditary algebras of type $𝔸̃_{p,q}$. In the second case detailed algorithms are given (Algorithms 4.5 and 5.5).