You have to adjust the indices (if you'll look at my original response, you'll note that there was a comment about that).  That is, you don't want to stop at the lowest index (r) if you are attempting to access L[r-1].  Instead, you have to stop at r+1.  Similarly when looping in the other direction.

That was why I had suggested

rng := rtable_dims(A);
start := lhs(rng);
finish := rhs(rng);

That assigns start/finish the initial and final indices of the rtable.  You could also use ?rtable_num_elems, however, that doesn't provide enough information if the rtable doesn't start at a known index.

That was why I had suggested

rng := rtable_dims(A);
start := lhs(rng);
finish := rhs(rng);

That assigns start/finish the initial and final indices of the rtable.  You could also use ?rtable_num_elems, however, that doesn't provide enough information if the rtable doesn't start at a known index.

Try this,

with(DynamicSystems):
sys := TransferFunction(1/(1+s)):
plts := BodePlot(sys, output=[magnitudeplot,phaseplot]):
plots:-display(Vector(plts));

You can create your own bodeplot procedure to do that automatically:

bodeplot := proc()
   plots:-display(Vector(DynamicSystems:-BodePlot(args, 'output=[magnitudeplot,phaseplot]')));
end proc:

I'm sorry, but I don't know how to interpret "in force".  Maybe you could attempt to rephrase that. 

Using mu(x,theta) for the axial-coordinate won't generate a cylinder, mu is periodic in theta. 

I'm sorry, but I don't know how to interpret "in force".  Maybe you could attempt to rephrase that. 

Using mu(x,theta) for the axial-coordinate won't generate a cylinder, mu is periodic in theta. 

Actually, would you rather have both graphs in one plot, say with the magnitude using the left-axis and the phase the right-axis?  Dual-axis plots weren't possible when ?DynamicSystems was released, but are now and that should be added as an option.  To do that now, do

with(DynamicSystems):
sys := TransferFunction(1/(1+s)):
plts := BodePlot(sys, output=[magnitudeplot,phaseplot]):
plotsetup(maplet); # only needed if not in Standard
plots:-dualaxisplot(plts[]);

Arrgggh.  Don't convert L to a list.  Leave it as an rtable.

The problem with your loop is that they are, essentially,

for j from 6 to 1 do ... end do;

That does nothing because the default step size is +1; you need to use the ?by keyword to set a negative step:

for f from 6 to 1 by -1 do ... end do;

Arrgggh.  Don't convert L to a list.  Leave it as an rtable.

The problem with your loop is that they are, essentially,

for j from 6 to 1 do ... end do;

That does nothing because the default step size is +1; you need to use the ?by keyword to set a negative step:

for f from 6 to 1 by -1 do ... end do;

To go backwards, use the by keyword in a for-loop, for example,

for i from 5 to 1 by -1 do
    ...
end do;

Rather than code a procedure for you, I'll give you a few suggestions.

Write a procedure that operates on an Array in-place:

cocktailsort := proc(A) ... end proc:

Use ?rtable_dims to extract a range that corresponds to the dims of A.  Then use ?lhs and ?rhs to extract the min and max values:

rng := rtable_dims(A);
start := lhs(rng);  # you may have to adjust these values depending on how you code the loops.
finish := rhs(rng);

To swap two elements, do

(A[i], A[i+1] ) := (A[i+1], A[i]);

To go backwards, use the by keyword in a for-loop, for example,

for i from 5 to 1 by -1 do
    ...
end do;

Rather than code a procedure for you, I'll give you a few suggestions.

Write a procedure that operates on an Array in-place:

cocktailsort := proc(A) ... end proc:

Use ?rtable_dims to extract a range that corresponds to the dims of A.  Then use ?lhs and ?rhs to extract the min and max values:

rng := rtable_dims(A);
start := lhs(rng);  # you may have to adjust these values depending on how you code the loops.
finish := rhs(rng);

To swap two elements, do

(A[i], A[i+1] ) := (A[i+1], A[i]);

I frequently run tasks in the background, so additional CPU usage will just slow them down.  However, I don't write books in the worksheet interface...

I tried it with Maple 13.02 on 64 bit linux, with an I5  and could get brief periods of usage near 44% (on one core).  On a P4 with 32 bit linux I could get get similar percentages. This is just typing text, with no returns.

A similar hack is to use the empty function to group the terms:

X3 := -((N1*X1*e2 + N2*X2*e1)*e3) / (e1*e2*N3):
algsubs(e3/e1/e2=``(e3/e1/e2), X3); 
                                              e3
                                            (-----) (N1 X1 e2 + N2 X2 e1)
                                             e1 e2
                                         - ------------------------------
                                                         N3

A call to expand evaluates the empty function call to its argument.

Something I frequently wish for is a built-in identity function.  Then one could do

algsubs((Id=``)(e3/e1/e2), X);

which seems nicer. Id := ()-> args works, but I'd prefer a builtin.

A similar hack is to use the empty function to group the terms:

X3 := -((N1*X1*e2 + N2*X2*e1)*e3) / (e1*e2*N3):
algsubs(e3/e1/e2=``(e3/e1/e2), X3); 
                                              e3
                                            (-----) (N1 X1 e2 + N2 X2 e1)
                                             e1 e2
                                         - ------------------------------
                                                         N3

A call to expand evaluates the empty function call to its argument.

Something I frequently wish for is a built-in identity function.  Then one could do

algsubs((Id=``)(e3/e1/e2), X);

which seems nicer. Id := ()-> args works, but I'd prefer a builtin.