RE: Re: for higher dimensions?

• To: mathgroup at smc.vnet.net
• Subject: [mg68585] RE: [mg68532] Re: for higher dimensions?
• From: "Tony Harker" <a.harker at ucl.ac.uk>
• Date: Fri, 11 Aug 2006 04:39:47 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```
I don't think there's any alternative to recasting your problem as a
conventional eigenproblem -- but it's not too messy to do so. For example:

mm = Array[a, {2, 3, 4, 5}]
MatrixForm[newm = Flatten[Transpose[Flatten[mm, 1], {3, 1, 2}], 1]]

Then a judicious application of Partition[] to the result will get you your
A matrix.

Tony Harker

Dr A.H. Harker
Department of Physics and Astronomy
University College London
Gower Street
London
WC1E 6BT

]->-----Original Message-----
]->From: AES [mailto:siegman at stanford.edu]
To: mathgroup at smc.vnet.net
]->Subject: [mg68585] [mg68532] Re: for higher dimensions?
]->
]->In article <eb9p00\$srh\$1 at smc.vnet.net>,
]-> "Adriano Pascoletti" <pascolet at dimi.uniud.it> wrote:
]->
]->> Yes. Use Eigensystem.
]->> For instance
]->>
]->> M = {{2, 0, -3}, {3, 5, 6}, {1, 1, -1}};esys = Eigensystem[M];
]->>
]->
]->Thanks -- but this, in my interpretation at least, is a 3 X
]->3 but still
]->*two-dimensional* (rows and columns) matrix.
]->
]->My current task is to find eigensolutions to a problem that
]->might be written most conveniently, with it's indices shown
]->explicitly, as
]->
]->   M_{i,j,m,n} A_{m,n}  = lambda A_{i,j}
]->
]->with M known and the objective being find a set of
]->eigenvalues lambda[k] and "eigenmatrices"  A_{i,j}[k] that
]->satisfy this equation.
]->
]->

```

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