Reputation
2,256
Top tag
Next privilege 2,500 Rep.
Create tag synonyms
Badges
3 12
Newest
 Nice Answer
Impact
~26k people reached

Feb
3
answered Combinations of multiple matching patterns
Feb
1
reviewed Approve Solving a quasi- or nonlinear PDE
Feb
1
comment NonlinearStateSpaceModel/OutputResponse gives doubled outputs
The example is a bit ways down in the documentation. wolfram.com/xid/0g7kxbwzgfy-nrn3sk
Jan
29
reviewed Approve A pointer to the array in p1=Table in Table =p0 Eror
Jan
29
revised NonlinearStateSpaceModel/OutputResponse gives doubled outputs
Corrected spelling
Jan
29
answered NonlinearStateSpaceModel/OutputResponse gives doubled outputs
Jan
18
comment Working Precision in nonlinear control systems
Does this work: Method -> {"NDSolve", WorkingPrecision -> ...}
Jan
13
comment Finding coefficient in expression
Turns out to also have the fewest characters (so far). But not the fastest!
Jan
12
answered Finding coefficient in expression
Jan
7
answered Matrix of Columns, I want just a regular matrix!
Nov
19
answered Building Butterworth Bandpass Filters
Nov
13
answered Extract left-upper triangular data from a square matrix-form list
Nov
13
answered Non-algebraic equation in the set of complex numbers
Nov
13
comment How do I put matrices next to each other?
ArrayFlatten is what you need.
Nov
12
comment Simple code to write differential equations in a matrix formulation
It is basically this: q2 = D[q, {t, 2}]; [Lambda] = {Subscript[F, x], Subscript[F, y]}; e = Join[q2, [Lambda]]; c = Thread[e -> 0]. You used Equal and I used Rule for 'function' in Thread[function[list1, list2]]. If list1 or list2 is not a list it is expanded to a list of identical elements.
Nov
12
comment Simple code to write differential equations in a matrix formulation
Fair enough. It all makes sense now.
Nov
12
revised Simple code to write differential equations in a matrix formulation
Updated answer after question was clarified
Nov
12
comment Simple code to write differential equations in a matrix formulation
Phew, I think I have finally understood your question. You just need to compute M and $\phi_q$. I will shortly update my answer. Why on earth did you use notation for force to denote Lagrange multipliers? That really threw me off.
Nov
12
comment Simple code to write differential equations in a matrix formulation
No! You left out the $Q_v$ in the wiki (which I have above as $Cv$). And again, to repeat myself, your $\phi_q$ (what is $C_q$ in the wiki) and $\lambda$ are completely irrelevant here. You haven't said what the constraints here. How can anyone here compute its Jacobian??
Nov
12
comment Simple code to write differential equations in a matrix formulation
This is how the equations are en.wikipedia.org/wiki/Multibody_system#Equations_of_motion. You don't have constraint equations in the question (so λ is irrelevant as of now) and I will update my answer shortly.