On Sat, Mar 28, 2015 at 5:10 AM, Animesh Saxena <animeshsaxena at icloud.com>

wrote:

> I was implementing automatic differentiation in haskell and was able to

> code the calculation part, but I wanted to extend it to show the symbols

> instead of just the final value.

>

> Anyway now I was hoping to print the actual symbols, so I was googling

> around for extending ?Show? typeclass for floating and Num, kinda similar

> pattern. Is this the right approach? Or I need to rethink the problem?

> Basically my aim is to do something like mathematica where if I specify

> D[f[x],x] then I get the answer in symbols.

>

>

The idea would be to write a new type that transport an human readable

representation as well as the actual value, then make it a Num, Floating

and so on instance so that you could just use ADif with this type to get a

representation of your action. You can look at simple-reflect

<

https://hackage.haskell.org/package/simple-reflect> for a simple

implementation of this idea you can directly use with your ADif. If instead

of a String, you transport an operation tree, you may even simplify your

result and get back almost a symbolic differentiation from your automatic

differentiation !

--

Jeda?

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