I do not have a specific Matlab code, but the following one is from python. The code is really easy to understand. the X_input and y_input, are the features and label data-sets, respectively. Just make some changes and you will have a nice code.
Salma Lahmar Data augmentation can be applied to any kind of signal (or data). The goal is to generalize to unseen data when a limited variety of conditions is observed in the dataset. This principle is applicable to images (rotation, zoom, flip, etc), speech (adding noises, reverberation, changing the speed/pitch, etc), videos (chunking, subsampling, etc) and can be performed in a image-like domain where the data is 2-dimensional (spectrogram for speech / frame for video) or directly on the original signal.
On my case, I have some data that I built them by simulation and I want to complete my database by data augmentation instead of using simulation because is laborious and time consuming
My inputs data are the parameter of building and my output is the energy consumud by the building and I use simulation software to calculate this energy.
What I want to do is to use data augmentation to vary more my parameters and calculate the energy without using ths Software .
Using a generative model (such as a GAN ; generative adversarial neural network) can be helpful. It has been tried in several domains (such as [1]) and seems to be able to generate unseen and useful data points consistent with the train data distribution (training it may be harder than classical models but many implementations for different kinds of GANs can be found on github).
Other simpler techniques have also been tested in older papers (early 2000's) exploring adding noise, interpolating or extrapolating between data points to generate new ones. It all depends on the kind of data you're working on, it's distribution and the amount of variability within the dataset.
Sorry I can't help. I don't think there is any generic domain-agnostic data augmentation toolkit out there, if you're not learning directly from data (using a neural network for example), or modeling your data distribution with some generative model (GMM, HMM, etc), some domain knowledge is needed to generate new data.