A method for determining a self-assembly pattern of a block copolymer confined inside a closed outline called the guiding outline, comprises the following steps, which are implemented by computer: a) choosing in a database a closed outline called the reference outline that is similar to the guiding outline, a self-assembly pattern of the block copolymer, called the reference pattern, being associated with the reference outline; b) applying a geometric transformation to a plurality of points of said reference pattern in order to convert them to respective points called image points of the self-assembly pattern to be determined. A computer program product for implementing such a method is provided.