Use, for example, the following scheme:

1. Put an interpreted MATLAB function into your model

2. Make changes in values you require

3. Get the local environment variables by "who"

4. Save the necessary ones into the parent ('base' in this case) environment

5. Find necessary blocks by "find_system"

6. Set necessary parameters by "set_param"

The problem is that Simulink loads the block parameters at start. You need set_param to update them during simulation.

I have used set_param but could not update the simin block parameters during simulation 

Write me a message tomorrow, maybe I'll send you an example code.

You can Tune the Parameters of the Simulink Blocks.

Kindly refer to the Links given below.

1.     http://in.mathworks.com/help/simulink/ug/using-tunable-parameters.html

Tunable Parameters

2.    http://in.mathworks.com/help/simulink/ug/updating-a-block-diagram.html

For your ready Reference the Relevant matter is given in the attached file.

P.S.

The Following Link will also be useful.

http://blogs.mathworks.com/seth/2011/03/08/how-do-i-change-a-block-parameter-based-on-the-output-of-another-block/

File attached.(item no. 3. in that file).

P.S.

Ok, here is a crude solution that worked for me. This function changes the vaule of the constant "tmp" from two files: "tmp1.mat" and "tmp2.mat".

when i tried to update simin block i get these error.

You're simply trying to assign to a non-existing parameter.

i have to update [Time, Output ] during simulation. I can update them in workspace but not in simulink. When i update i have the old values and after restarting the simulation i get the new values 

I have the same problem and be solved using assignin function.

https://ch.mathworks.com/help/matlab/ref/assignin.html#d123e54121