ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 20 Apr 2022 06:20:22 +0200Non-dimensionalization of a Partial Differential Equationhttps://ask.sagemath.org/question/62056/non-dimensionalization-of-a-partial-differential-equation/Hello all, I am interested in replacing the variables of a Partial Differential Equation (PDE) for their non-dimensional counterparts and then group together the dimensionless numbers. I think I would only need to be able to replace the variables and also the derivative operators (as in a change of variables $\hat{x}=x/L$), grouping the dimensionless numbers can be done by hand.
It is a similar procedure to what is being done here: (en.wikipedia.org/wiki/Non-dimensionalization_and_scaling_of_the_Navier%E2%80%93Stokes_equations) . I was wondering if this can be done with SAGE.salazardetroyaWed, 20 Apr 2022 06:20:22 +0200https://ask.sagemath.org/question/62056/Divergence of inverse squarehttps://ask.sagemath.org/question/55608/divergence-of-inverse-square/ Hello,
I tried to calculate the divergence of 1/r^2*e_r, but I got zero, where it should have been 4*pi*dirac_delta(r*e_r)
E.<r,th,ph>=EuclideanSpace(coordinates="spherical")
v=E.vector_field([1/r^2,0,0])
v.div().display()
Results is
E^3 --> R
(r, th, ph) |--> 0
Can this be considered as a bug?
curios_mindSun, 07 Feb 2021 00:15:43 +0100https://ask.sagemath.org/question/55608/Gradient, Divergence, Curl and vector productshttps://ask.sagemath.org/question/10104/gradient-divergence-curl-and-vector-products/Are there implementations of vector product and the nabla operator yet? I can't find anything.KiMon, 21 Oct 2013 12:40:22 +0200https://ask.sagemath.org/question/10104/Detecting series divergence automaticallyhttps://ask.sagemath.org/question/8481/detecting-series-divergence-automatically/I'm writing an interact to let my students see graphs of sequences and of sequences of partial sums. But, I also want the interact to print the sum of the infinite series, if it converges.
Is there a way I can detect whether the sum converges within the interact? I need some automation here. I don't see that the "sum" command returns any sort of error value that flags whether the series converges or not. It just produces lots of errors.
Thanks!
calc314Wed, 16 Nov 2011 15:27:41 +0100https://ask.sagemath.org/question/8481/