This is a public github repo (https://github.com/mgharamti/EnKF_EnOI_ES_EnKS.git) that compares: 

• Ensemble Kalman filter (EnKF)
• Ensemble Optimal Interpolation (EnOI)
• Ensemble Smoother (ES)
• Ensemble Kalman Smoother (EnKS)

in a toy 1D system. Code is quite simple, straight-forward and written in MATLAB. The intent of this tool is to shed some light on the differences between the filter and smoothers in a simple OSSE framework. 

If you decide to try it out, please feel free to issue a PR for any bugs/mistakes .. 

Have fun!