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RE: Question from a biologist

  • To: mathgroup at
  • Subject: [mg70457] RE: [mg70410] Question from a biologist
  • From: "David Park" <djmp at>
  • Date: Tue, 17 Oct 2006 02:58:15 -0400 (EDT)

The trouble with your posting is that you don't tell us anything about how
you generate your differential equations, or how many variables and
parameters you have. There are certainly ways to generate differential
equations and distinguish the parameters from the variables.

You might be able to use a statement like

SetAttributes[{p1, p2, p3}, Constant]

before you generate the ODEs.

Or, if you already have the equations you could use a rule.

deqns2 = deqns1 /. {p1'[_] -> 0, p2'[_] -> 0, ...}

David Park
djmp at

From: tnad [mailto:terry_najdi at]
To: mathgroup at

I'm trying to simulate some chemical reactions in mathematica using ODEs. I
want to keep some of the variables (the parameters in the differential
equations) constant during the simulation. Right now, I have to look for the
first derivative of every variable in a sea of differential equations and
set it to zero. Is there a more "elegant" way to do this in mathematica?

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