I found my mistake, matter closed.
Am Mo., 7. März 2022 um 13:22 Uhr schrieb Peter Stahlecker <
peter.stahlec...@gmail.com>:
> I tried on a 'small' example, and N_y.suns({sm.Derivative(q1, t): u1})
> worked just fine !!
> No idea, what is going on.
>
> Am So., 6. März 2022 um 15:18 Uhr schrieb Pe
The sympy.srepr() function can help debug things, as it shows the "true"
form of the expression. Maybe a variable is printing differently than what
it is.
Jason
moorepants.info
+01 530-601-9791
On Mon, Mar 7, 2022 at 1:23 PM Peter Stahlecker
wrote:
> I tried on a 'small' example, and N_y.suns
I tried on a 'small' example, and N_y.suns({sm.Derivative(q1, t): u1})
worked just fine !!
No idea, what is going on.
Am So., 6. März 2022 um 15:18 Uhr schrieb Peter Stahlecker <
peter.stahlec...@gmail.com>:
> I am playing around with an ellipse, which rotates in 3D.
> In its own coordinate syste
I typically use `.xreplace()` if I'm simply swapping one variable for
another. But subs or replace should work. Sympy mechanics uses t =
me.dynamicsymbols._t internally. Are you using your own defined t that
different? If soe the derivative terms could print the same but aren't
actually the same sy
I am playing around with an ellipse, which rotates in 3D.
In its own coordinate system A, its equation of course is
x**2/a**2 + y**2/b**2 + z**2/c**2 = 1
A rotates relative to N, the generalized coordinates are q1, q2, q3,
dq1/dt = u1, etc.
I express the rotated ellipse in N, by using
