Framework segment structure contains segment structure (binded with retrieval part) and initial guess for each pixel. If a value of initial guess is -999, it will be ignored and the value in setting file will be used like initial guess.
Segment edges has information of neighbors
Initial guess for each pixel. This initial guess will be used instead of values in settings file if the values here are different than -999. Otherwise values from settings file will be used
Sensor data which it will run inside retrieval code. It is binded with Fortran file.