Adapted from Chapter 5 of 'Saṅgītaratnākara - A Study' by R.Rangaramanuja Ayyangar, 2nd Ed.
The Druta Mēru chart tabulates the number of permutation steps with 0, 1, 2..13 Druta elements in thirteen prastāra-s.
In a similar manner, the Laghu, Guru, Pluta Mēru charts tabulate the number of permutation steps with 0, 1, 2 .. 13 Laghu, Guru and
Pluta elements in thirteen prastāra-s.
Copious directions for their construction have been given. The base is surmounted vertically by others progressively decreasing
in number till a single block perches at the top. The raison d'etre for the charts and the numbers in the columns is explained
at great length step by step by both the commentators. The numbers, added up column-wise vertically and posted at the bottom of
the diagrams, tally with the Saṅkhyā table.
The Saṃyoga Mēru chart tabulates the number of steps in each prastāra with a specified combination of elements.
The representation in the commentaries is rearranged here to present the element combinations in serially increasing number of Druta-s.
The columns in this table represent the various combinations of the tā elements. These elements, Druta (d), Laghu (l), Guru (g) and Pluta (p)
combine in 15 different ways: 'd', 'd-l', 'd-g', 'd-p', 'd-l-g', 'd-l-p', 'd-g-p', 'd-l-g-p'; 'l', 'l-g', 'l-p', 'l-g-p'; 'g', 'g-p' and finally 'p'.
If we arrange these combinations first in terms of their value and then in order of the hierarchy of elements (d, l, g, p) we get the desired
combinations used in the Saṃyoga Mēru table:
'd' (0.5), 'l' (1.0), 'd-l' (1.5), 'g' (2), 'd-g' (2.5), 'l-g' (3), 'p' (3), 'd-l-g' (3.5), 'd-p' (3.5), 'l-p' (4),
'd-l-p' (4.5), 'g-p' (5), 'd-g-p' (5.5), 'l-g-p' (6), 'd-l-g-p' (6.5)
The figures in parentheses represent the mātrā count of each combination.
To view the mēru charts click on these links: Druta Mēru | Laghu Mēru | Guru Mēru | Pluta Mēru | Saṃyoga Mēru