The code represents a generalization of the Multisignal 1-D wavelet decomposition. I have simply wrote a simple routine to extract the full tree out of the Matlab "mdwtdec" function available within the wavelet toolbox.
The code is efficient and very simple, and is mainly written for feature extraction from the WPT tree using an overlapping windowing approach.
To use the code: the main function is getmswpfeatV00, read inside the code for an example.
** Kindly cite either of the following papers if you use this code **
 R. N. Khushaba, A. Al-Jumaily, and A. Al-Ani, “Novel Feature Extraction Method based on Fuzzy Entropy and Wavelet Packet Transform for Myoelectric Control”, 7th International Symposium on Communications and Information Technologies ISCIT2007, Sydney, Australia, pp. 352 – 357.
 R. N. Khushaba, S. Kodagoa, S. Lal, and G. Dissanayake, “Driver Drowsiness Classification Using Fuzzy Wavelet Packet Based Feature Extraction Algorithm”, IEEE Transaction on Biomedical Engineering, vol. 58, no. 1, pp. 121-131, 2011.
-Version V01 is for multiple signals (if you have enough memory)
-Version V00 is for individual signals (one at a time, same as above just iterate this for multiple signals).