Firedrake meeting 2020 10 12

Date and time 2020-10-05 15:00UTC (16:00BST)

Action Items

Pick Chair and Minuter.
ALL: (ongoing) triage the open issues and confirm if they are indeed still open (and perhaps provide labels)
??: Build master on centos to catch errors
RK: Report back on quadrature estimation
KS: Complex merge

Minutes

Present: David Ham, Connor Ward, Koki Sagiyama, Paul Kelly, Sophia Vorderwuelbecke, Colin Cotter, Lawrence Mitchell, Jack Betteridge, Tom Gregory, Rob Kirby

Apologies: Reuben Nixon-Hill (note new surname!)

DH: Complex has landed

RK: Report back on quadrature moved to "the future"

DH: Move meeting to Weds from next week (still at 1600 GMT+1)

Also note that there is an hour's disparity the following week due to Daylight savings differences between different countries.

JB: Numpy bug

Finally successfully installed on MacOS, we have working install script now.

Can also import Firedrake, but we need a hack:

export DYLD_INSERT_LIBRARIES=/usr/local/opt/openblas/lib/libblas.dylib:/usr/local/opt/openblas/lib/liblapack.dylib

We should discuss whether we are happy with such a hack.

Conclusion, this is a bodge. Can be fixed by adding correct rpath to offending modules that are loading the incorrect shared libraries. Action JB fix this.

KS: Subspace

Refactor tsfc/driver.py

gem construction
impero_c construction
kernel construction

etc.

firedrake/tsfc_interface.py

Ex: Jacobian assembly:

all_gem_expr = []
split form according to indices (i, j) -> subform
    split subform according to test/trial subspaces (test_sub, trial_sub) -> subsubform
       gem_expr = compile_ufl(subsubform, ...)
  ->   gem_expr = transform(gem_expr, test_sub, trial_sub) (test_sub and trial_sub know right transformation rule, such as rotation)
       all_gem_expr.append(gem_expr)
    kernel = construct_kernel(all_gem_expr)

Question:

Masked is still a ufl class (now defined in Firedrake), but disappear before calling compile_ufl. This is convenient when we take action and derivative, but not sure if this is a good practice.

KS: Masked is "UFL", but defined in Firedrake.

DH: This is an issue if transforms are called on UFL expressions.

LM: Can we just merge TSFC driver refactroring standalone?

DH: This will allow us to have a hiatus on this work.