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RE: Re: how to explain this weird effect? Integrate

  • To: mathgroup at
  • Subject: [mg46431] RE: [mg46411] Re: how to explain this weird effect? Integrate
  • From: "David Park" <djmp at>
  • Date: Wed, 18 Feb 2004 00:36:54 -0500 (EST)
  • Sender: owner-wri-mathgroup at


And it's nice when Mathematica can do things like that. But there is also a
matter of efficiency. Value substitutions are quite common in Mathematica.
They also occur whenever you write a routine with arguments, or a With
statement. If Mathematica has to check if the expression has singular
values, and if the substitution creates one of those singular values, and
then has to try various kinds of limits, it's going to become very
convoluted and slow down EVERYTHING.

Maybe in the future when we get quantum computers and more advanced
algorithms we'll see more of what you hope for. And already Mathematica has
added extra capability with Assuming and the Assumptions options.

David Park
djmp at

From: steve_H [mailto:nma124 at]
To: mathgroup at

But that is exactly my point. I wanted Mathematica to act as if it was a
human. (A very smart human at that).

All what I am saying is that Mathematica should have taken that extra step
without me having to tell.

The way I look at it, is that when I tell a computer algebra program
to solve X, then I expect the program to do what it can and apply
any number of different steps and 'tricks' to solve X.

I do not have to tell it to do step 1 first, then step 2, then if it
can't do step 2, then try this trick first, and then do step 2, etc...

All what iam saying is that taking the limit in this case is NOT an
additional step becuase it would have lead to the solution I wanted.

I guess it is a design issue. Some folks here do not seem to agree
with this, but I think this is how a computer algebra system should
work. So, may be we should drop this subject and leave it at that.
We agree to diagree.


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