On May 26, 1:50 pm, Friedrich Hagedorn <[EMAIL PROTECTED]> wrote:
>
> The problem is that
>
> In [26]: type(dvec)
> Out[26]: <type 'list'>
>
> so you have to convert your 'vector' to a sympy
>
> In [27]: mdvec=Matrix(dvec).T
great this works perfectly! I redid my definitions of the vectors and
I simply defined dvec=diff(vec,t) and dvecM=Matrix(dvec).T
> In [31]: mdvec*(1/x**2)
> Out[31]:
> ⎡ d d d ⎤
> ⎢-sin(φ(t))*──(φ(t)) ──(x(t)) ──(z(t))⎥
> ⎢ dt dt dt ⎥
> ⎢─────────────────── ──────── ────────⎥
> ⎢ 2 2 2 ⎥
> ⎣ x x x ⎦
>
> (subs the x**2 by your sqrt(...))
>
> The In[31] must be so unconvenient because otherwise the '/' fails.
> It seems to be a bug.
I didn't have this problem though:
I simply defined the unit vector along 'dvec' by:
evec=dvecM/sqrt(s.dot(dvec,dvec))
Note that I had to use the 'Matrix' and divide my the norm of the
'list'. Kinda weird...
Thanks Friedrich!
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