Subject: [Viper-dev] Arrow scaling

From: Anders Logg <[email-masked]>
Date: Fri, 18 May 2007 22:14:29 +0200

Can something be done about choosing a reasonable scaling for arrows
in vector plots? How about setting the maximum length to something
like

    D / num_vertices^(1/d)

where D is the diameter of the domain, and d is the space dimension?

Take a look as the DOLFIN demo in src/demo/pde/mixed-poisson and you
will see what I mean... :-)

/Anders

---

From: Ola Skavhaug <[email-masked]>
Date: Mon, 21 May 2007 14:47:45 +0200

> will see what I mean... :-)

The test doesn't run:
  Using direct solver.
  *** Warning: UMFPACK must be installed to peform a LU solve for uBlas
matrices. A Krylov iterative solver will be used instead.
  Solving linear system of size 2112 x 2112 (uBlas Krylov solver).
terminate called after throwing an instance of 'std::runtime_error'
  what():  *** Error: Zero pivot detected in uBlas ILU preconditioner in row
1600.
Aborted (core dumped)

I have libufsparse (and dev package) installed, and I need these because of
octave2.9. libumfpack conflicts with libufsparse. What is the solution?

Ola
 
> /Anders
> _______________________________________________
> Viper-dev mailing list
> [email-masked]
> http://fenics.org/mailman/listinfo/viper-dev

---

From: Anders Logg <[email-masked]>
Date: Mon, 21 May 2007 14:56:08 +0200

> octave2.9. libumfpack conflicts with libufsparse. What is the solution?

I don't have a good solution to the libufsparse/libumfpack problem.
Anyone else?

I've attached the solution (sigma.xml.gz). Let's see if it goes
through or it's too large for the mailing list (21K).

/Anders

---

From: "Garth N. Wells" <[email-masked]>
Date: Tue, 22 May 2007 12:37:01 +0200

> I don't have a good solution to the libufsparse/libumfpack problem.

There is a bug in the Debian/Ubuntu libufsparse package 
(http://bugs.debian.org/cgi-bin/pkgreport.cgi?pkg=libufsparse;dist=unstable). 
Use libumfpack instead.

The problem is that libufsparse is not linked correctly to BLAS. You 
need to supply -lblas, etc when compiling DOLFIN. Since this is a 
libufsparse problem, I didn't want to add a test for BLAS to the DOLFIN 
configure process.

Garth

> DOLFIN-dev mailing list
> [email-masked]
> http://www.fenics.org/mailman/listinfo/dolfin-dev
>