This section defines some general functions, which are common utilities for wavelet transformation and other functions.
| Name | Description |
|---|---|
| _fft | An external function to carry out FFT |
| cumSum | Cumulative sum of a vector. Data type is Real. |
| cumSumInt | Cumulative sum of a vector. Data type is Integer |
| diff | Difference between every two adjacent elements of a vector |
| fft | Fast Fourier transform |
| fftShift | Shift zero-frequency component to center of spectrum |
| findIndex | Find the location of a value in a monotone vector |
| filterBank | Get the four wavelet filters based on a given scaling filter |
| ifft | Inverse fast Fourier transform |
| innerProduct | Inner product of two same length vectors |
| interpL | One-dimensional linear interpolation |
| midVector | Extract the middle part of a vector |
| nStdIfft | Inverse non-standard 1-D fast Fourier transform |
| quadReverse | Quadrature mirror of a given vector |
| sinc | Sinc function |
| upsample | Up-sampling of a vector (insert a zero after every element except the last one) |
| wavConv | Fully convolving of a data vector and a filter vector for wavelet transform |