[Getdp] Q: Lanczos error
スズキ
ohyeahq at yahoo.co.jp
Mon Jun 28 02:29:11 CEST 2004
Hi,
I'm new to getdp (on Windows). I tried to solve a
simple eigenvalue problem using lanczos, and got an
error: "Lanczos algorithm not available with the GSL".
Questions:
(1) I took a look at the source code and found that
lanczos routines are intentionally disabled when
HAVE_GSL is defined. Why is that?
(2) Is there a way to solve eigenvalue problems,
either by enabling lanczos, or by using another
algorithm?
(3) I found a simple wave equation example in the
mailing-list archive, in which the formulation is
in time domain and resolution contains lanczos. Does
it mean that specifying lanczos automatically convert
time-FEM into frequency domain, so I don't have to
rewrite FEM manually for lanczos? The example goes
like this:
Formulation {
{ Name Wave; Type FemEquation;
Quantity {
{ Name u; Type Local; NameOfSpace Hgrad; }
}
Equation {
Galerkin { DtDt [ 1/c[] * Dof{u} , {u} ];
In Omega; Integration I1; Jacobian JVol;
}
Galerkin { [ c[] * Dof{d u} , {d u} ];
In Omega; Integration I1; Jacobian JVol;
}
Galerkin { [ - dfdt[] , {u} ];
In Gamma_f; Integration I1; Jacobian
JSur; }
}
}
}
Resolution {
...
{ Name Wave_pvp;
System {
{ Name A; NameOfFormulation Wave; }
}
Operation {
GenerateSeparate[A];
Lanczos[A, 19, {1:5}, 0];
SaveSolutions[A] ;
}
}
}
Thank you for your help.
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