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FEniCS
Default degree 3 quadrature on triangle inefficient?
Original report by Miklós Homolya (Bitbucket: miklos1, GitHub: miklos1).
FIAT has generic rules for generating arbitrary order collapsed quadrature on triangles and tetrahedra ("canonical"). It also has a few hand-written rules for low-order quadrature on triangles and tetrahedra ("default"), which are presumably more efficient. The default rules indeed have fewer quadrature points than the canonical ones in all cases except one: degree 3 quadrature on the triangle.
The default scheme uses 6-point quadrature in this case, while the canonical scheme only uses 2 x 2 = 4 points.
Original comment by Jan Blechta (Bitbucket: blechta, GitHub: blechta).
Fix in branch jan/fix-issue-27 and next.