Re: Solving a symbolic complex linear system of equation.
- To: mathgroup at smc.vnet.net
- Subject: [mg77944] Re: Solving a symbolic complex linear system of equation.
- From: Szabolcs <szhorvat at gmail.com>
- Date: Wed, 20 Jun 2007 05:33:23 -0400 (EDT)
- Organization: University of Bergen
- References: <f58dlb$8lc$1@smc.vnet.net>
Please state the question precisely.
Fo wrote:
> Suppose that I want to solve symbolically a system of lienar equations
> defines as:
> $Ax=B$ , where A is a complex matrix, B is a complex vector and x is
> the vector of the unkown.
You say you want to solve A x = B. If A is invertible, the solution is
x = A^-1 B. Inverse[] can be used to compute A^-1.
> The elements of the A matrix (that is simmetric) are in the form
> $A_{ij}e^{i phi_{ij}}$.
> I tried in several ways but I couldn't define the variables $A_{ij}$
> and $ phi_{ij}$ as real.
Any complex number can be written in the form A Exp[I*phi] (where A and
phi are real), so I do not see the point here.
Or is a '=' sign missing and you mean that all the elements are complex
numbers of magnitude 1? Even if they are, the solution is still A^-1 B.
Do you mean that you would like to specify that some of the variables
are real when simplifying the end result? For this, look up the syntax
for Simplify[], and use something similar to Simplify[Sqrt[a^2], a
\[Element] Reals] to specify that a variable 'a' is real.
> I tried using the package Algebra`ReIm` and to define each variable as
> z/:Im[z]=0.
> But it does not the wanted result and also I've already read the help
> page for ComplexExpand[].
What kind of result do you expect? It would be helpful if you posted
the complete problem, with some more detailed explanation.
> Thank you, every suggestion will be helpful.
> Fortu
>
>