@Axel Vogt wrote:

So users say "please set 'by time' as default" and Maple's answer is "do it yourself".

Note that the option to "do it yourself", i.e., to set the order, applies only to Answers. There is no way to set the order for the Replies (aka Comments) to the Answers. That order may even change between reloads of the same page.

Describe the algorithm, and I'll implement it in Maple.

@Kitonum Which goes to show that you'll need some variation in your X values if you want to get a meaningful answer. Otherwise, the answer is going to be a = X[1], b=0, c=0, regardless of the Y or Z values.

@Kitonum Can you explain why you used the divisor 7 rather than 8 in procedure P?

@Christopher2222 I think that Maple should detect the case where the weights are all positive integers and, in that case, use the standard formula.

@pepegna90 Replace RowDimension with LinearAlgebra:-RowDimension and likewise for ColumnDimension.

If you have further questions, please upload a worksheet, not a screenshot. If the worksheet depends on a data file for the Matrix, then upload the datafile also.

@Carl Love Here's an easier way: Fix the positions Alan=1 and Amy=8. Since there are eight seats, that makes Alan and Amy next to each other. All the other other constraints are about a direct next-to relationship; they never deal with a gap of two or more spaces. We've accounted for the circularity by saying that 1 is next to 8. The rest of the constraints can be specified with the ordinary NextTo and Separated. I know it all sounds flaky, but it is easy to verify that the solutions thus generated satisfy all the constraints (under my interpretation of the constraints). So the whole problem can be done without any custom constraint procedures.

I have some difficulty figuring out what the problem's author means by "either" when it is in boldface and combined with "not" (as in "Alan does not sit next to either Debbie or Emily.")

I did the problem, and I got multiple solutions. Do you have a source that claims a unique solution? (Most problems billed as puzzles have a unique solution.) I'll post my solution in a separate Answer, later.

@smith_alpha You could use c:= rand(0..1)() every time you want to generate a random number (a random bit in this case). But if you want to generate multiple random bits, it is more efficient to do c:= rand(0..1) once, and then call c() every time you want a new one. The c:= rand(a..b) generates a procedure which generates a random number; it not itself generate the random number.

@noor-al-bahrain The real root is not a rational number. You cannot find the fraction because the fraction doesn't exist.

There is a difference between convert(x, rational) and convert(x, rational, exact). Consider

x:= evalf(1/3);
                       0.333333333333333
convert(x, rational);
                               1/3
convert(x, rational, exact);
                        333333333333333/1000000000000000

@henrylyl When you pass a Vector (or other rtable) as a procedure argument, it only passes a pointer to the object rather than making a copy of the object. The same is true when you assign one Vector (or other rtable) to another with :=. So, if A is Vector, after the assignment

B:= A;

any changes made to B will be made to A also, and vice versa. To avoid this, you need to use the copy command:

B:= copy(A);

Now A and B are completely separate objects. In your case, you can make your procedure call with copy like this:

SLRrepeatedsample(copy(X), copy(Y), 2, .95);

Or you can use the copy command with the assignment inside the procedure.

You have only one loop, not a nested loop.

@henrylyl Two problems I see immediately. The first is that LinearFit is spelled with a capital F. You have a lowercase f in several places. The second is Why is x a Vector? It only has a single value. In the line beginning ySE:=, you try to use x as if it were a scalar.

What kind of data are in the Arrays cosArr2, k1, and alpha? If it is not floating point, could you make it so?

I think that the problem can be done. Instead of NextTo, we need a custom relational constraint CircNextTo (and its negation). See the long comment ahead of procedure `Know/Rel`. These procedures are much easier to write than the general procedural constraints that I wrote about yesterday. See the seven examples that I put in the code, starting with SameBlock.

Then to make the rotational symmetry unique, we arbitrarily make Alan = 1. Since left and right are not used in the problem, we also have flip symmetry. We know Amy is next to Alan, so we make Amy = 2.

To express a disjunction of constraints, use OR([constraints]). There can be any number of constraints more than one. Example: OR([NextTo(Amy, Alan, PN), NextTo(Brad, Beth, PN)]). Note that both letters of OR are uppercase.

I was wrong about the negation of the NextTo constraint, and I've changed my previous answer regarding that. Please reread it. The negation of NextTo(A, B, V) is Rel(Separated, A, B, V, [1]). Since Separated is an export of the dynamic module, a constraint using it must appear after the with is executed.

The circular arrangement does indeed complicate matters. I don't know if this problem can be solved by the package. I'll be thinking about it as I fall asleep tonight.