How to evaluate parts of an expression, but not other parts?

*To*: mathgroup at smc.vnet.net*Subject*: [mg122659] How to evaluate parts of an expression, but not other parts?*From*: Julian Francis <julian.w.francis at gmail.com>*Date*: Sat, 5 Nov 2011 04:45:28 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Dear all, I'd like to use the TreePlot function to visualise the expression of a dynamic programming problem I am working on. If I have something like: ( (a+b) + (c+d ) Mathematica helpfully simplifies this to: a + b + c + d But I'd prefer it to be in the original form. I can't write Hold[ ( (a+b) + (c+d) )] because I do want a,b,c & d to be evaluated. I want to write something like: Hold[ ( (Evaluate[a]+Evaluate[b]) + (Evaluate[c]+Evaluate[d]) ) ] But this just leaves the Evaluate expressions unevaluated. Any help greatly appreciated. Thanks, Julian.

**Follow-Ups**:**Re: How to evaluate parts of an expression, but not other parts?***From:*Bob Hanlon <hanlonr357@gmail.com>

**Re: How to evaluate parts of an expression, but not other parts?***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>