Tag broadcast and reduce
Reported by Jed Brown | September 19th, 2008 @ 04:38 PM
The broadcast is needed for getting a global numbering of entities. The reduction is needed to ensure consistent element order when regions are constrained against shared faces.
Comments and changes to this ticket
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Jed Brown November 21st, 2008 @ 08:09 PM
(from [5ea812358c091a21ff35f15f5f89adf9c0c956c8]) Replace explicit passing of work arrays with VLA.
Start with plumbing for element mappings. The first implementation will just use nodal coordinates.
Also, replace some hairy indexing with VLA pointer types. External tests show that GCC produces better inner-loop code for
double (A)[N]; / A[i][j] in inner loop */
than
double A; / A[i*N+j] in inner loop */
In fact, the assembly produced at -O3 with the VLA-pointer seems roughly equivalent to hoisting
double restrict a = &A[i*N]; / a[j] in inner loop */
out of the innermost loop. GCC -Wcast-qual produces a warning for
const double a; const double (b)[2] = (const double (*)[2])a;
claiming that
cast discards qualifiers from pointer target type' but it is not clear to me that this is actually the case.Signed-off-by: Jed Brown jed@59A2.org http://github.com/jedbrown/dohp/...
-
Jed Brown November 21st, 2008 @ 08:09 PM
(from [5ea812358c091a21ff35f15f5f89adf9c0c956c8]) Replace explicit passing of work arrays with VLA.
Start with plumbing for element mappings. The first implementation will just use nodal coordinates.
Also, replace some hairy indexing with VLA pointer types. External tests show that GCC produces better inner-loop code for
double (A)[N]; / A[i][j] in inner loop */
than
double A; / A[i*N+j] in inner loop */
In fact, the assembly produced at -O3 with the VLA-pointer seems roughly equivalent to hoisting
double restrict a = &A[i*N]; / a[j] in inner loop */
out of the innermost loop. GCC -Wcast-qual produces a warning for
const double a; const double (b)[2] = (const double (*)[2])a;
claiming that
cast discards qualifiers from pointer target type' but it is not clear to me that this is actually the case.Signed-off-by: Jed Brown jed@59A2.org http://github.com/jedbrown/dohp/...
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An implementation of the ``dual order hp'' version of the finite element method. This project targets parallel domain-decomposition methods for strongly coupled nonlinear problems with PDE constraints.
Jed Brown