How to Simplify a system of equations and find possible substitions (symbolic toolbox?

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Torben 2024-1-9

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https://ww2.mathworks.cn/matlabcentral/answers/2067931-how-to-simplify-a-system-of-equations-and-find-possible-substitions-symbolic-toolbox

评论： Walter Roberson 2024-1-9

Hello,

i've got 8 symbolic expressions and i want to simplify this system of equations together. So i've there identical expressions in 2 or more equations the number of mathematical computations can be reduced.

It is a symbolic problem using the symbolic toolbox.

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Dyuman Joshi 2024-1-9

What would you do with the simplifed system? Solve it for the parameters?

Torben 2024-1-9

Using the 8 derivations directly for some kind of online RLS-algorithm

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Walter Roberson 2024-1-9

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If you use matlabFunction and request that it be written to a file, then the default is to optimize. The optimization step involves searching for common subexpressions and assigning them to variables and reusing the variables.

The end result is a .m file that is intended for numeric calculation.

Caution: not very long ago, optimization was badly broken, so test before trusting.

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Steven Lord 2024-1-9

If you're not using matlabFunction you could use the subexpr function.

Walter Roberson 2024-1-9

I haven't tested over the last couple of releases, but not very long ago, the optimization phase had a series of problems for a number of years. It was completely unusuable for longer expressions.

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