@asa12 The essential part of the computation is the B.B^*; the simplify, fnormal~, and zero are only there to remove the spurious infintesimal imaginary parts caused by round-off error.

I don't know in which version of Maple the notation B^* for the conjugate transpose (aka Hermitian transpose) was introduced. If your Maple 15 objects to this, then B^%H will certainly work (the H standing for Hermitian).

Regarding the "definition" of orthonormality that you claim that your book uses: I think that you're misreading it, and certainly it's wrong. The correct definition is

@John Fredsted Here are two facts that can help you to produce session-independent results:

1. Code that uses randomly generated data will execute using the same random numbers in different sessions as long as you start from restart and don't use the randomize() command.

2. The order that items are listed in Maple sets is session independent. This was not always the case, but it's been true for several years now.

@Markiyan Hirnyk Why replace plottools with plots? Neither is necessary. Nor is the presence of plottools the source of any trouble. The command plot is top-level, not in any package.

@zia9206314 Executing your worksheet, and then executing the command

p1;

I get this plot

It only takes about one second.

@Just_Some_Guy Yes, I saw the attached file. It contains what you've done so far. I want to see an example of what you want as the final product: a plot with error bars.

@tazatel I think that your main problem is that decimal numbers need to be entered with a decimal point rather than a comma. In other words, what you have entered as 0,0215 must be entered as 0.0215 or .0215 or 2.15e-2, etc.

I need a clarification of the problem statement. What does "exactly two points lie astride every [one] of these lines" mean? Using the colors in your example, does it mean "exactly two [blue] points lie astride every [one] of these [red] lines"? Still, I don't know what "astride" means. My first guess is that it means that if we form the six line segments determined by the blue points, then each of the red lines is intersected by exactly one of these line segments. However, that isn't true for the example diagram. A second guess is that each of the eight red rays and eight red line segments is intersected by exactly one of the line segments determined by the blue points. In that case, we need to deal with the complication that there are some triple intersections.

@Markiyan Hirnyk I base my comments just on careful observation of MaplePrimes over the past three years. Jon Mcloone has made no post in the past three years. If he had, I certainly would've upvoted it. I read everything on MaplePrimes, so I certainly would've seen it. I've seen Comments by Mcloone, but not Posts.

Some Comments by Mcloone can be found in the thread http://www.mapleprimes.com/posts/201237-Comparisons

His Users' page is http://www.mapleprimes.com/users/JonMcloone

@Markiyan Hirnyk I inverted the relationship between n and N from the original formulation. Thus I treat n rather than N as the symbolic variable, and I solve for it. This is handled by the lines

SolN:= [solve(b/c=n, N)]:
N:= SolN[1]:

I do this because it's easier to solve for an integer variable.

Your application depends on a code file, knot.txt, which hasn't been supplied.

@want to be a permanent vegan As we discussed earlier, that if-then-else clause needs to replaced by piecewise!

Can you find on the Web an example of the type of plot that you are talking about?

@Muhammad Usman You were very eager (to the point of being repetitive) to get an Answer, and now you've been silent for two days. So, does my most recently posted code work for you?

@want to be a permanent vegan I read your updated code, and I don't understand why odeplot is not satisfactory for you. Yes, you can use the output= Array(L) option to dsolve to pass in a list L of any number of independent-variable values. You'll receive as dsolve's return value an Array with the corresponding dependent-variables values (and some other stuff). Yes, you can make the spacing of the independent-variable values as fine as you want (for some extremely fine spacings you may need to adjust dsolve's error-control options). And yes, you can use these values to make a plot. But all these things can be handled better by odeplot, especially if you use its numpoints option.

@want to be a permanent vegan 

Please don't mix the MaplePrimes threads. That thread is about your if/piecewise problem. Please repost your latest Reply from that thread here, in this thread.