The invention provides a device for producing a magnetic resonance image. The device comprises a collecting unit adapted for collecting k space samples that are located on a non-Cartesian grid in a non-Cartesian coordinate space or non-uniformly located on a Cartesian grid in a Cartesian coordinate space, the non-Cartesian/Cartesian coordinate space adapted to be decomposed into a plurality of subspaces, each of which extends along one or more coordinate axes of the non-Cartesian/Cartesian coordinate space; a weight calculation unit (203) adapted for calculating a decomposed sample density weight function of the k space samples in each individual subspace and determining a density weight function in the non-Cartesian/Cartesian coordinate space via a multiplication of the decomposed sample density weight functions of the k space samples in the plurality of subspaces; a gridding unit adapted for interpolating the k space samples in the non-Cartesian/Cartesian coordinate space onto a uniform Cartesian grid in a k space based on the density weight function of the k space samples in the non-Cartesian/Cartesian coordinate space; and a reconstructing unit adapted for reconstructing the magnetic resonance image based on the interpolated k space samples. By means of the invention, fast, preferably on-demand, calculation of the sampling density weights may be achieved.