  The Universe at the present epoch is found to be a network of matter
over-dense and under-dense regions. To date, this picture of the Universe is
best revealed through cosmological large-volume simulations and large-scale
galaxy redshift surveys, in which, the most important step is the appropriate
identification of structures. So far, these structures are identified using
various group finding codes, mostly based on the friends-of-friends (FoF) or
spherical over-density (SO) algorithms. Although, the main purpose is to
identify gravitationally bound structures, surprisingly, the mass information
has hardly been used effectively by these codes. Moreover, the methods used so
far either constrain the over-density or use the real unstructured geometry
only. Even though these are key factors in the accurate determination of
structures-mass information, hardly any attempt has been made as yet to
consider these important parameters together while formulating the grouping
algorithms. In this paper, we present our proposed algorithm which takes care
of all the above-mentioned relevant features and ensures the bound structures
by means of physical quantities, mainly mass and the total energy information.
We introduced a novel concept of physically relevant arm-length for each
element depending on their individual gravity leading to a distinct linking
length for each unique pair of elements. This proposed algorithm is thus
fundamentally new that, not only able to catch the gravitationally bound, real
unstructured geometry, it does identify it roughly within a predefined
physically motivated density threshold. Such a thing could not be
simultaneously achieved before by any of the usual FoF or SO-based methods. We
also demonstrate the unique ability of the code in the appropriate
identification of structures, both from large volume cosmological simulations
as well as from galaxy redshift surveys.
