Why Does This Definition of a Piecewise Function Produce a Warning Message?

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Kareem Elgindy 2022-1-31

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评论： Kareem Elgindy 2022-2-2

采纳的回答： Benjamin Thompson

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MATLAB issues a warning when defining the below piecewise function

syms y(x); y(x) = piecewise(x<1, x+1, 1<=x<2, x-1);

But when I write

y(x) = piecewise(x<1, x+1, (1<=x) & (x<2), x-1);

the warning message disappears. Could someone point to an example where those two ways of defining a piecewise function produce different results? It seems here that they give identical results.

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采纳的回答

Benjamin Thompson 2022-1-31

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This is just a warning about good programming syntax. Good programming style is to never leave order of operations in doubt, and add parenthesis where needed to clarify order of operations. While a <= b <= c is good mathematical notation, it may no be clear to a compiler or interpreter how the expression must be evaluated.