Re: [Maxima-discuss] Stop simplifying a subexpression

[Stavros M. <mac...@gm...>]

One trick is to wrap the expression in a lambda, which blocks
simplification:

lambda([],2+2) => lambda([],2+2)

But lambda([],2+2)+lambda([],2+2) =>
     2*lambda([],2+2)

To block that, you can construct unique lambdas:
    lambda([z23],2+2) + lambda([z24],2+2)
doesn't simplify.

Then you can write a simple function to remove these lambdas.

If this isn't clear, please ask for more info.

      -s

On Thu, Aug 7, 2025, 16:42 Michael Gough <inn...@gm...>
wrote:

> i need simplification to work on most expressions. I need a way to wrap a
> subexpression so it doesn't simplify. I'm thinking of changing the operator
> so instead of x+x I would use mikeplus(x,x). I won't define mikeplus, so it
> won't simplify, but the tree will still contain the subexpression in some
> form. I think that's what I need.
>
>
> On Thu, Aug 7, 2025 at 1:27 PM Barton Willis <wi...@un...> wrote:
>
>> Setting the option variable 'simp' to false disables simplification; for
>> example,
>>
>> (%i101) simp : false$
>>
>> (%i102) xxx : x+x;
>> (%o102)                                        x + x
>>
>> (%i103) xxx - 2*x;
>> (%o103)                                    (x + x) - 2 x
>>
>> (%i104) simp : true$
>>
>> (%i105) xxx - 2*x;
>> (%o105)                                          0
>>
>> But when simp is false, few things are guaranteed to work.  One of the
>> few (only?) uses of setting simp to false is to define a simplification
>> rule, such as 0^0 = 1. Maybe another legitimate use is an educational or
>> math tutorial use.
>>
>> Users often want to set simp to false, but I think it rarely turns out
>> well, and it usually invokes the question: Why do you need to set simp to
>> false? Can you explain what you are trying to do? There might be a better
>> option than turning off simplification.
>>
>> ------------------------------
>> *From:* Michael Gough <inn...@gm...>
>> *Sent:* Thursday, August 7, 2025 3:05 PM
>> *To:* <max...@li...> <
>> max...@li...>
>> *Subject:* [Maxima-discuss] Stop simplifying a subexpression
>>
>> Caution: Non-NU Email
>>
>> I need to prevent maxima from maxima from simplifying a subexpression.
>> Let’s say I have x+x.
>>
>> Try as I might, I can not keep it from becoming 2x.
>>
>> Pkease note that x+x is just an example of a subexpression.
>>
>> Thanks in advance!
>> Mike
>>
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