[Getdp] Newbie question: viewing B on a contour in MagSta_a

[Garret Brady]

Hi all,
In the 2d magnetostatics a example: I'd like to view
B-normal on a 1-d contour in the 2-d Domain.  Viewing
{a} on the contour (called 'Ubound') is easy:

{ Name boundary_a ; Value { Local { [ {a} ]    ;
 In Ubound   ; Jacobian MyJac ; } } }

Works fine, but

{ Name boundary_b ; Value { Local { [ {d a} ]    ;
 In Ubound   ; Jacobian MyJac ; } } }
throws 
Error     : Null determinant in 'ChangeOfCoord_Form2P'

UAny help would be gatefully appreciated.
All the best
Garret Brady
IT Blanchardstown, Dublin 15, Ireland.

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