c2d tustin's method calculation

How does the continuous to discrete conversion work using tustin's method? More specifically what is the exact algorithm used for this replacement going from 's' to 'z'.

[Swarooph]

Does this documentation page help?

[Bernie Floeder]

So me and 3 others have used that approximation to do a continuous to discrete conversion on a first order Low Pass Filter, yet when comparing the expected magnitudes with our computed by hand method vs. the c2d command we get different numbers (typically + or - 0.005) and I was hoping to see the function itself to see how our computations differed.

[Swarooph]

You can access code to c2d function but not sure if that is going to help. Do the following to see the location of the file. For me they are as follows:

>> which -all c2d
C:\Program Files\MATLAB\R2017a\toolbox\control\ctrlobsolete\c2d.m
C:\Program Files\MATLAB\R2017a\toolbox\shared\controllib\engine\@DynamicSystem\c2d.m  % DynamicSystem method

Access the SECOND one here to see the code. Again, this might mean you will need to keep going deeper into the code. Not sure if that's the easiest way to address this concern.

If you showed your work by hand and an example MATLAB result it will help here to compare.