algorithmic modeling for Rhino

hi all,

I have written a simple script (in VB) that solves a formula for its zero points. it works ok, but I want to feed the formula into the component like into the "function evaluate"-component.

is there any chance to do this?

perhaps its easier to make this in python, but I don't get the python code working.

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Replies to This Discussion

Hi Laurenz,

You can use the eval function to evaluate the string (that's the equation you have) as if it was regular python expression.

So why don't you create a string input and feed in the expression?


David Rutten

Hi Djordje,

thank You very much for introducing me into the magic of eval(). It was exactly what I was looking for! Now it works for my needs.

One drawback: the eval()-function seems to slow down the whole thing significantly (hard-coded the component took 78ms, with eval() it took 3.5s !)


Yes, looks like eval function can be slow.

Still, I tried using the equation string directly (assigning it to a variable inside of ghpython component), not importing it from outside. And it lowered the computation time to 100ms.

You can speed up eval() by using lambdas

f = eval('lambda x: ' + expressionString)

and call the function like


thank You both, now it works at reasonable speed. I think what causes the delay was the position of the "eval"-command, so every time the function was called, the "eval" translated the input one more time.






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