ASKSAGE: Sage Q&A Forum - Latest question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Thu, 21 Nov 2013 01:25:00 -0600Matrix/Tensor derivative for Stress Tensorhttp://ask.sagemath.org/question/8119/matrixtensor-derivative-for-stress-tensor/I need to do define/calculate the following stress tensor in an elegant way:
$T_{i,j} := -p \delta_{i,j} + \eta (\partial_i v_j + \partial_j v_i)$
where i,j can be x,y,z and
$\partial_i v_j := \frac{\partial v_j}{\partial i}$
I've found the sage-function kronecker_delta for the first term, but I am having problems with the two partial derivatives.
Thanks in advance!packomanWed, 18 May 2011 10:20:46 -0500http://ask.sagemath.org/question/8119/Matrix equations and derivativeshttp://ask.sagemath.org/question/10759/matrix-equations-and-derivatives/Hello!
I am completely new to Sage and Python.
In order to get knowledge about Sage I'd like to find a way to express an equations like these
http://stats.stackexchange.com/questions/14827/how-to-calculate-derivative-of-the-contractive-auto-encoder-regularization-term
User with nickname fabee had posted derivatives of contractive autoencoder regularizer, and I want to reproduce these results in Sage. It's a big challenge for Sage newbies like me.
A few first attempts do not succeed so can you show me the way to do this task?
newbieThu, 21 Nov 2013 01:25:00 -0600http://ask.sagemath.org/question/10759/partial fraction decomposition function for multivariate rational expressionshttp://ask.sagemath.org/question/8429/partial-fraction-decomposition-function-for-multivariate-rational-expressions/Hi all:
I'd like to extend Sage's partial fraction decomposition function in the QuotientField class to a function that works on quotients of *multivariate* polynomials. To this end, i've found it convenient to store a rational expression $F = P/(Q_1^{e_1} \cdots Q_m^{e_m})$ as a Python list of the form [P,[Q_1,e_1],...,[Q_m,e_m]], where $Q_1,\ldots,Q_m$ are the irreducible factors of $F$'s denominator. Let's call these special kinds of lists 'widgets'. I have several auxiliary functions that manipulate widgets.
Code design questions for you. Should i make a new class for widgets, and if so, where in the Sage tree of modules should i put this class? If not, where do i put the auxiliary functions that manipulate widgets?
Thanks for your attention.
Alex araichevWed, 02 Nov 2011 13:11:23 -0500http://ask.sagemath.org/question/8429/