1. A system comprising a hardware sparse-dense transform unit for transforming sparse elements into a dense matrix, the system comprising: a sparse element access unit in the sparse-dense transform unit and for accessing multiple sparse elements of a dense matrix, wherein the sparse element access unit includes: a request identification unit configured to: receive, over a node network, a request for particular sparse elements stored in one or more data shards; determine that the sparse element access unit in which the request identification unit is located is assigned to handle a subset of the particular sparse elements; and in response to determining that the sparse element access unit in which the request identification unit is located is assigned to handle the subset of the particular sparse elements, generate an indication for accessing the subset of the particular sparse elements; at least one processor for fetching, based on the indication, one or more sparse elements of the subset of the particular sparse elements; and a concatenation unit configured to: generate an output dense matrix based on a transformation that is applied to at least the one or more sparse elements.