Comment 6 for bug 997739
Revision history for this message
| Johan Hake (johan-hake) wrote Re: [Bug 997739] Re: Rank analysis is wrong | #6 |
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0e1f616
(Get the code!)
On 05/10/2012 08:54 PM, Marie Rognes wrote:
> There is a difference between tensor rank and form rank. You are printing
> the tensor ranks. The form rank would be number of Arguments.
> So, in your example:
>
> (grad(u) + Delta) * grad(v) = grad(u)*grad(v) + Delta*grad(v)
>
> The first term on the right-hand side has form rank 2 (there is a TestFunction
> and a TrialFunction involved) while the other has form rank 1 (just a TestFunction).
Tensors, smensors!!
> DOLFIN can only assemble (and FFC only generate code for) forms
> in which all terms have the same (form) rank.
> In short, you can't add a matrix and vector together.
Will target this as a bug for sfc :)