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Re: programming in mathematica

• To: mathgroup at smc.vnet.net
• Subject: [mg42412] Re: [mg42389] programming in mathematica
• From: Tomas Garza <tgarza01 at prodigy.net.mx>
• Date: Sat, 5 Jul 2003 03:10:57 -0400 (EDT)
• References: <200307040533.BAA10454@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

First, a point on syntax: multiplication requires inserting a "*" or leaving
an empty space between factors. Second, if I understand correctly, you wish
to substitute the variable z by a - h? In that case, use ReplaceAll (/.),
e.g.

In[2]:=
g*(z^h/(a*z^b + c*z^d + e*z^f)) /. z -> a - h
Out[2]=
(g*(a - h)^h)/(a*(a - h)^b + c*(a - h)^d + e*(a - h)^f)

This may be applied to any expression, in your case the sum of all the
fractions at the same time.

Tomas Garza
Mexico City


 ----- Original Message ----- 
From: "Pickard Laura R" <LRPICKARD at mail.dstl.gov.uk>
To: mathgroup at smc.vnet.net
Subject: [mg42412] [mg42389] programming in mathematica


> Hi all,
>
> I cannot view the newsgroup as I am stuck behind a firewall here, but if
you
> could email me any help with this, it would be much appreciated.
>
> I am new to using mathematica (currently I have version 4.1, should be
> getting a trial copy of version 5 soon, my os is winNT).  I have been
> attempting to do some programming and need to automate a calculation, to
be
> done far too many times to attempt it manually.
>
> A previous calculation outputs a sum of fractions in terms of z, all are
of
> the form gz^h/(az^b+cz^d+ez^f).  I need to do a calculation involving the
> numbers a-h.  I would like to be able to input the fraction, automatically
> assign the correct numbers from it to the variables a-h, then do the
> calculation and output the result.  Ideally, if I could input the sum of
all
> the fractions directly as output from the previous calculation and do this
> for each one, then output an answer which is the sum of the results for
each
> fraction that would be best.  I have found my way around programming in
> basic functions, but am unsure as to how to input a standard form of
> equation and automatically assign the values to the variables for
> calculation.
>
> Any help would be greatly appreciated.
>
> Thanks,
>
> Laura Pickard.
>
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• References:
  • programming in mathematica
    • From: Pickard Laura R <LRPICKARD@mail.dstl.gov.uk>