how to make matlab and simulink connected and automatic working

I wrote the algorithm to calculate the external force for a mass-spring-damping system in matlab and also made the model to simulate the mass motion in simulink, but two files are separated ( one is in matlab and other one in simulink). I would like to connect them together and only set parameters in matlab to run the whole system ( after the algorithm, calculate the force, and then import the force to simulink to calculate the mass motion, done). so, how to connect them or how to make this work? Thanks

[Kaustubha Govind]

Does the MATLAB function need to run in the simulation loop of the model (ie, at every time-step), or does it run just once and have its output imported as an input signal in Simulink?

[Vivi]

Just run once and export the result, then use the result as an input signal in Simulink.