Replacement problem
- To: mathgroup at smc.vnet.net
- Subject: [mg36906] Replacement problem
- From: carlos at colorado.edu (Carlos Felippa)
- Date: Tue, 1 Oct 2002 04:46:03 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
These expressions are condensation of larger ones (about 700 lines or so each) but they illustrate random substitution failures in 4.2. Question: how can the substitution Sqrt[...]->Q always be made to work? The help file under ReplaceAll, ReplaceRepeated, etc, does not address this problem. Thanks f=B*(A+Sqrt[X+Y+Z])+C/(Sqrt[X+Y+Z]/4*F^2); Print[(f/.Sqrt[X+Y+Z]->Q)//InputForm]; B*(A + Q) + (4*C)/(F^2*Sqrt[X + Y + Z]) (* fails *) g=B*(A+Sqrt[X+Y+Z])+C/(Sqrt[X+Y+Z]*4*F^2); Print[(g/.Sqrt[X+Y+Z]->Q)//InputForm]; B*(A + Q) + C/(4*F^2*Sqrt[X + Y + Z]) (* fails *) h=B*(A+Sqrt[X+Y+Z])+C/(Sqrt[X+Y+Z]+4*F^2); Print[(h/.Sqrt[X+Y+Z]->Q)//InputForm]; B*(A + Q) + C/(4*F^2 + Q) (* works *)