Implements triangular filterbank given in . Returns matrix of M triangular filters (one per row), each K coefficients long. The triangular filters are between limits given in R (Hz) and are uniformly spaced on a warped scale defined by forward (h2w) and backward (w2h) warping functions. For example, h2w and w2h can be hz2mel and mel2hz functions, respectively, in which case trifbank returns a mel filterbank, i.e., a filterbank of triangular filters uniformly spaced on the mel scale. Other forward and backward warping functions can be specified to arrive at arbitrary warped triangular filterbanks.
 Huang, X., Acero, A., Hon, H., 2001. Spoken Language Processing: A guide to theory, algorithm, and system development. Prentice Hall, Upper Saddle River, NJ, USA (pp. 314-315).