how to avoid rounding off error in simulink calculations?
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Hi, I have a simulink model including a level 2 S function block. The code in the s function ia a numerical scheme that solves a PDE . When this code is run as a script alone the results are exactly accurate..but when the model is simulated they results differ from the accurate ones. I have checked and compared the results thoroughly and I guess in the very first step there is a rounding off error which is causing the results to differ. With each iteration the error is getting summed up. Is there any way to avoid this error?? Please help. I am using all variables in double data type. Please answer. Thanks.
Kaustubha Govind on 23 Jun 2014
The difference between 46.7889e5 and 46.7890e5 is 10, which is too large to be a rounding error. Most likely, what is happening is that the From Workspace block is interpolating your data because the time-steps corresponding to your data points don't match with the simulation solver time-steps exactly. You may want to either adjust the time values in your workspace data, or uncheck the "Interpolate Data" option on the From Workspace block dialog.