Suppose I have an expression that I want to symbolically differentiate using the Calculus package, and then create a function in Julia evaluating this expression at a given value of the variable x. For instance, using Calculus expression_F=“x^3” expression_f= differentiate(expression_F,:x) f(x)=…

[image] pdenapo: expression_F=“x^3” Note that this is a string and not an expression. julia> F(x)=eval(:(x->$expression_F)) As with any function, this means that when we execute F(x) we get the result of computing the function body. The function body is eval(:(x->$expression_F)) which is …

Try f = eval(:(x->$expression_f)). That creates a function expression containing the expression to evaluate, so that x is bound within the expression. Then the function expression is evaluated, producing a function object you can call.

Many thanks! However, I’m not really understanding how this works. For if, I just define my expression by hand as in the following example, it doesn`t work! julia> expression_F=“x^3” “x^3” julia> F(x)=eval(:(x->$expression_F)) F (generic function with 1 method) julia> F(2) #11 (generic functio…

How shoudl I evaluate a symbolic expression for a given value of a local variable?

New to Julia

kristoffer.carlsson October 10, 2018, 6:49pm 5

Also, please see PSA: how to quote code with backticks.

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How shoudl I evaluate a symbolic expression for a given value of a local variable?

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