On 4/9/25 06:52, Léonhard YU wrote:
But the result is very large. Is there any operation that I did wrong?
Results are:
Cycle 0:
Number of active cells: 3712 (by partition:
616+624+616+616+624+616)
Number of degrees of freedom: 17226 (by partition:
3177+2934+2763+2934+2790+2628)
Assembling system... norm of rhs is 1.80592e+10
*l2_norm of error system 22537.2 *
I'd like to point out a perspective I've raised here before: 22537 is
large if you're a snail and it refers to a distance of 22537 kilometers.
It is not large if you're a human and it refers to a duration of 22537
microseconds. The point is: 22537 is neither large nor small by itself
-- whether it is depends on what it is you are measuring, what the units
are, and what you compare it against.
In the current context, you are measuring the residual. You should be
comparing it to the norm of the right hand side, for example. Look at
residual.l2_norm() / right_hand_side.l2_norm()
to see whether the norm of the residual is large or small. In other
words, follow Daniel's suggestion of looking at the *relative* error.
Best
W.
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