[sage-support] Re: Trouble getting *collect* to work with derivatives.

Sage has recently acquired a large set of tools relative to manifolds . A look at these tools and related tutorials/references may be in order… HTH, Le samedi 23 janvier 2021 à 23:17:26 UTC+1, cseb...@gmail.com a écrit : > What you intend to do isn’t really cl

[sage-support] Sage Crash Report

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Re: [sage-support] Re: Trouble getting *collect* to work with derivatives.

Emmanuel But my question is more simple than that. I just want to know why the collect method was not able to collect all the terms with the given second derivative. On Sun, Jan 24, 2021, 2:15 AM Emmanuel Charpentier < emanuel.charpent...@gmail.com> wrote: > Sage has recently acquired a large se

Re: [sage-support] Re: Trouble getting *collect* to work with derivatives.

Probably because “the given second derivative” has a “computed operator”… BTW : var("x,y,z,t,v,c") f=function("f") xp=(t-v*x)/sqrt(1-v^2/c^2) yp=y zp=z tp=(t-v*x/c^2)/sqrt(1-v^2/c^2) foo=(sum(map(lambda u:derivative(f(xp,yp,zp,tp),u,2), (x, y, z)))-derivative(f(xp,yp,zp,tp),t,2)/c^2).factor()

Re: [sage-support] Re: Trouble getting *collect* to work with derivatives.

Dear Christian, Given the specifications, I suspect that the function collect only works for variables. And indeed sage: expr = (x+y)*(z+t) + (x+y)*(1+z^2) + 2 sage: expr (z^2 + 1)*(x + y) + (t + z)*(x + y) + 2 sage: expr.collect(x+y) (z^2 + 1)*(x + y) + (t + z)*(x + y) + 2 Instead

Re: [sage-support] Sage Crash Report

at the bottom of the log you see ImportError: /home/mathieu/opt/SageMath/local/lib/python3.8/site-packages/sage/matrix/matrix_modn_sparse.cpython-38-x86_64-linux-gnu.so: undefined symbol: _ZNK6Givaro7IntegercvNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEB5cxx11Ev which is an indication t

[sage-support] Re: Trouble getting *collect* to work with derivatives.

I suspect you want to collect wrt. the second partial derivatives of f(x,y,z,t) with respect to x,y,z,t ; evaluated at xp,yp,zp,tp. Those are not the same as the partial second derivatives of f(xp,yp,zp,tp) with respect to (x,y,z,t). If you inspect what derivative(f(xp, yp, zp, tp), x, 2) gives

Re: [sage-support] Calling Words in a function gives an error

On Thursday, January 21, 2021 at 7:21:52 AM UTC-8 Nikos Apostolakis wrote: > Dear Vincent, > > Thank you very much, that fixes it. > > IMHO this is a bug though, or at least an inconsistent behavior. Most of > the time Sage silently coerces things to the appropriate type so commands > just wor

Re: [sage-support] Re: Trouble getting *collect* to work with derivatives.

What are computed operators? Are those the D[0, 0] things? How avoid those? Is that same as second derivative of 1st variable? On Sun, Jan 24, 2021, 11:33 AM Emmanuel Charpentier < emanuel.charpent...@gmail.com> wrote: > Probably because “the given second derivative” has a “computed operator”… >