MATLAB: How to write u= exp(1/((x-x_0)(x-x_1))) for x_0

matlab function

 u =@(x) vif(x>x0&x<x1,exp(1./((x-x0).*(x-x1))),0)
I need a function that can work with the @(x).

Best Answer

vif = @(condition, when_true, when_false) condition .* when_true + (~condition) .* when_false;
Note: this will not work if infinity is produced by the unselected side . For example, vif(x > 0, 1./x, 1) will not work for x = 0: even though the condition x>0 is not true for x=0, the 1./x would still be evaluated, giving inf, and when that was multipled by the 0 (false) of the condition x>0 that would be 0*inf which is nan.
If you need code that is able to handle the case where the expression might give infinity where the condition is not selected, then you will need a true function instead of an anonymous function. (Or you will need some obscure and ugly hacks involving subsexpr() and subsasgn() and multiple helper anonymous functions.)
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