How to get E**(-x), not 1/E**(x) ?
- To: mathgroup at smc.vnet.net
- Subject: [mg9717] How to get E**(-x), not 1/E**(x) ?
- From: ma zhanwen <mazw at mail.phy.ornl.gov>
- Date: Tue, 25 Nov 1997 00:06:13 -0500
- Sender: owner-wri-mathgroup at wolfram.com
Hello,
When I input an expression which containing natural logarithm exp(-x),
where x is a symbol, and I want to get the fortran form output. For
example, If the input is :
FortranForm[ y*Exp[-x] ] where y is an arbitrary expression.
the output will be :
y/E**(x)
Of course it is not wrong. But if I copy the output into a Fortran
program, when x is assigned a enough large positive value , the Fortran
program will overflow. But if it is y*E**(-x) , there will be no
problem. You may say that why not change y/E**(x) to be y*E**(-x)
yourself , It is because I have a great number of this kind of
expressions. It is a hard work to change them one by one and it is very
easy to make mistakes.
So can you tell me how to force Mathematica to give me y*E**(-x), not
y/E**(x) ??
Many thanks for your help
Zhanwen Ma
Oak Ridge National Lab.
Physics Division
Oak Ridge ,TN 37831-6354