# Nested Function stuck on iteration update

I want to solve the Sparse Extended Information Filter Slam described by Dr. Sebestian Thrun in Probabilistic Robotics.I stuck in some nested function.

The algorithm is described in page 309 in this book at Table 12.1

Algorithm is like that:

1.Algorithm SEIF_SLAM_known_correspondence($\xi_{t-1}$,$\Omega_{t-1}$,$\mu_{t-1}$,$u_t,z_t,c_t$):

It has four steps:

1.Motion Update

1. Measurement Update

2. Update state estimation

3. Sparsification

Motion Update:

Algorithm SEIF_motion_update($\xi_{t-1},\Omega_{t-1},\mu_{t-1},u_t$)

....... Algorithm body.....

Return $\bar\xi_{t},\bar\Omega_t,\bar\mu_t$

Measurement Update

Algorithm SEIF_measurment_update($\bar\xi_{t},\bar\Omega_t,\bar\mu_t,z_t,c_t$)

Algorithm body.....

Return $\xi_t,\Omega_t$

Now as per algorithm in motion update of SEIF the return value is called in measurement update. I want to know when this type of situation occurred means one function return value is called by a other function Is that call is iterative? If the function body of motion update iterate in a loop then after execution of 1st iteration calling function (measurement update) call this or after full execution of motion update function then measurement update call it?   • I can't fully understand the question. This is plain procedural code, with a "main" function calling the others, in the given order. There is no recursion here, only some loops. The results of the first functions calls are used to call the next functions. What is the issue here? – chi Sep 16 '18 at 13:24
• en.wikipedia.org/wiki/Return_statement – D.W. Sep 16 '18 at 19:05
• @chi I want to know the sequence of called function and calling function. – Encipher Sep 17 '18 at 17:31