Spectral decomposition based fast pressure integration algorithm (SD-FPI)

Integrating 2D or 3D grdient fields

Introduction for SD_FPI code
The code could integrate a 2D or 3D pressure gradient field to get the pressure field, which is a necessary procedure for PIV-based pressure reconstruction. The code also works for integrating any other gradient fields, just replacing the input pressure gradient fields.
The returning result for this code is the least-square solution for
(∂p/∂x=f(x,y,z);
∂p/∂y=g(x,y,z);
∂p/∂z=h(x,y,z);
f(x,y,z),g(x,y,z),h(x,y,z) are input 3D scalar fields. The solving algorithm is based on the spectral decomposition, which has been reported by Wang et al. (2017). The time-cost and memory consumption for running this code are pretty low.

Reference:
Wang C, Gao Q, Wei R, Li T, Wang J (2017) Spectral decomposition‑based fast pressure integration algorithm. Exp Fluids 58:84

Wang C, Gao Q, Wei R, Li T, Wang J (2017) Weighted divergence correction scheme and its fast implementation. Exp Fluids 58:44