  Gamma-ray bursts (GRBs) are typically classified into long and short GRBs
based on their durations. However, there is a significant overlapping in the
duration distributions of these two categories. In this paper, we apply the
unsupervised dimensionality reduction algorithm called t-SNE and UMAP to
classify 2061 Fermi GRBs based on four observed quantities: duration, peak
energy, fluence, and peak flux. The map results of t-SNE and UMAP show a clear
division of these GRBs into two clusters. We mark the two clusters as GRBs-I
and GRBs-II, and find that all GRBs associated with supernovae are classified
as GRBs-II. It includes the peculiar short GRB 200826A, which was confirmed to
originate from the death of a massive star. Furthermore, except for two extreme
events GRB 211211A and GRB 230307A, all GRBs associated with kilonovae fall
into GRBs-I population. By comparing to the traditional classification of short
and long GRBs, the distribution of durations for GRBs-I and GRBs-II do not have
a fixed boundary. We find that more than 10% of GRBs-I have a duration greater
than 2 seconds, while approximately 1% of GRBs-II have a duration shorter than
2 seconds.
