Re: [deal.II] Gradient of the shape function wrt natural coordinate system?
Exactly what I was looking for! Thank you so much Professor Bangerth. Have a great one, Shawn On Sun, Oct 14, 2018 at 1:47 PM Wolfgang Bangerth wrote: > On 10/14/2018 11:57 AM, Yuxiang Wang wrote: > > > > While I can use the shape_grad function to get the gradient of the shape > > function with respect to the real cell coordinates, would there be a way > to > > get the shape_grad with respect to the reference natural coordinates? > For > > example, for shell element (that I'm working on), I have the global > > coordinates (x, y, z) for a point and also a natural coordinate system > (r, s, t). > > > > One possibility is that I can use the chain rule and the jacobian matrix > to > > get that value, but it'll be very computationally inefficient. Could > anyone > > please help? > > I think you are asking for the *unmapped* shape functions as they are > defined > on the reference cell. That's something you can get from the finite > element > itself via the >FiniteElement::shape_grad() > function or its implementation in derived classes. > > The gradient of the shape functions mapped to a particular cell in a mesh > can > be obtained via FEValues::shape_grad(), which I think is what you are > referring to above. > > Best > W. > > -- > > Wolfgang Bangerth email: bange...@colostate.edu > www: http://www.math.colostate.edu/~bangerth/ > > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to a topic in the > Google Groups "deal.II User Group" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/dealii/-s1Dc9sbPE4/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > dealii+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Yuxiang "Shawn" Wang, PhD yw...@virginia.edu +1 (434) 284-0836 -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [deal.II] Gradient of the shape function wrt natural coordinate system?
On 10/14/2018 11:57 AM, Yuxiang Wang wrote: > > While I can use the shape_grad function to get the gradient of the shape > function with respect to the real cell coordinates, would there be a way to > get the shape_grad with respect to the reference natural coordinates? For > example, for shell element (that I'm working on), I have the global > coordinates (x, y, z) for a point and also a natural coordinate system (r, s, > t). > > One possibility is that I can use the chain rule and the jacobian matrix to > get that value, but it'll be very computationally inefficient. Could anyone > please help? I think you are asking for the *unmapped* shape functions as they are defined on the reference cell. That's something you can get from the finite element itself via the FiniteElement::shape_grad() function or its implementation in derived classes. The gradient of the shape functions mapped to a particular cell in a mesh can be obtained via FEValues::shape_grad(), which I think is what you are referring to above. Best W. -- Wolfgang Bangerth email: bange...@colostate.edu www: http://www.math.colostate.edu/~bangerth/ -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[deal.II] Gradient of the shape function wrt natural coordinate system?
Dear all, While I can use the shape_grad function to get the gradient of the shape function with respect to the real cell coordinates, would there be a way to get the shape_grad with respect to the reference natural coordinates? For example, for shell element (that I'm working on), I have the global coordinates (x, y, z) for a point and also a natural coordinate system (r, s, t). One possibility is that I can use the chain rule and the jacobian matrix to get that value, but it'll be very computationally inefficient. Could anyone please help? Best, Shawn -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
