Find a loop do define these matrices, even for large values of n. Record the Matrix Mn 

all i,j=1,2,13,..,n for example 

N := `<|>`(`<,>`(1, 2), `<,>`(2, 2))

P := `<|>`(`<,>`(1, 2, 3), `<,>`(2, 2, 3), `<,>`(3, 3, 3))

Q := `<|>`(`<,>`(1, 2, 3, 4), `<,>`(2, 2, 3, 4), `<,>`(3, 3, 3, 4), `<,>`(4, 4, 4, 4))

Please help!!!

Hello,

       I have a huge sparse matrix (1.5e6 x 1.5e6) of both symbolic or non-symbolic form. When I export matrix using ExportMatrix command, it is not writing the matrix in order of rows and columns. To further explain the problem,

          Let A be that huge sparse matrix. I am using

                    ExportMatrix("matrix.mtx",A,format=MatrixMarket)

We expect the output to be,

 1 1 0.1

 1 10 0.65

.

.

.

But it is writing the output as

 

100 1 0.25

100 25 0.65

Hence it is not writing in order. What is the way we can force it to write in order? I do understand using for loop will consume more time.

I have two equations:

and I need to extract the coefficients of x0 and xp0 (to build a matrix; but that is not the issue). So I use coeffs:

coeffs(op(2,X),x0);

coeffs(op(2,XP),x0);

xp0

While I can live with the first result (for X) (not that I like it), the fact that the 2nd one (for XP) has a completely different structure prevents any kind of algorithmic extraction of the coefficients (and the second one of course is 0) for further use. I tried the form of coeffs with a third argument (a name which gets the result assigned) but the same result. This example is a real case, obviously a trivial one and others will be much more involved so I really would like this to work. And yes, I did "collect" before using coeffs (not that it was needed here).

Any ideas out there?

Mac Dude.

I am trying to plot a function f(x).  Within the definition of f(x) I have some parameters, e.g., a, b, c tha have been defined.  Then these three parameter define a new parameter R.

The function is f(x)=R x.

a := 1;              Define a
1

b := 2;              Define b
2

c := 3;               Define c
3

R = a+2*b+3*c; Define R from a, b, c

R = 10 + 2 b~ (it should had given me 14)

F(x):=R*x;  Define the function
x -> R x

plot(R*x, x = -5 .. 5);   RECEIVE ERROR
Warning, expecting only range variable x in expression R*x to be plotted but found name R

I also tried to define R as R(a,b,c) and then F as F(R,x)...

but still it doesnot work.

Can anyone direct me to the right solution?

Thanks in advance.

NM

Hello All,

I have had a few questions that have come up while working on a Maple Assignment for my Calculus III class. I was wondering if anybody could help me with these questions, as well as show me how to enter them in Maple. Here are the questions I have been struggling with.

1. In the xy-plane, graph the ellipse ((x-4)^2)/(4))+(y-4)^2=1 and two level curves of F(x,y)=x^3+y^3-3xy that just touch the ellipse.

                  a. What do we know about the gradients of F and the ellipse at those points?

                  b. Use your graph to approximate the minimum and maximum values of F subject to the constraint ((x-4)^2)/(4))+  (y-4)^2=1.

      2. A company manufactures a product using inputs x,y,z according to the production function Q(x,y,z)=20x^(1/2)y^(1/4)z^(2/5). The prices per unit are $7 for x, $12 for y, and $18 for z.

                 a. Create the cost function

                 b. The company wants to produce 2500 products. Estimate the minimum cost by using the graph of the level surfaces of the cost function (from part a) together with the production constraint.

Any help you could give me would be much appreciated. Thanks!!

In some tutorials for certain "Maple-words" a name "command" is used, while others use "function".

What is the difference between "function" and "command" in Maple?

I have list for a:=[11110, 10101,100,10101], but, this list i want assume that all number is base 2..
so, how i want to convert to base 10?

Is it possible to use Unicode characters in  textplot  command? In the application that I'm developing, the signs of the chess pieces should be used.

I am trying to figure out how to enter tensors using the new Physics package in 17.02. For my first, presumably simple example, I am trying to reproduce the Lorentz transformation in Special Relativity:

X^μ' = Λ_ν^μ X^ν

where

Λ_ν^μ = [{γ, -γβ, 0, 0}, {-γβ, γ, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}]

X^ν = [x0, x1, x2, x3]^T

My Λ tensor Defines just fine; I do

(which, upon <Enter> is labeled (1)), and then

Define((1))

and this suceeds. However, when I do the X vector:

which is labeled (2), then the Define((2)) function returns the following error:

Error, (in Physics:-Define) expected right-hand-side of tensor definition as an algebraic tensorial expression, or a Matrix or an Array, representing the evaluation rule for the tensor X[`~nu`]; received: Vector(4, {(1) = x0, (2) = x1, (3) = x2, (4) = x3})

So my question is, what is the correct syntax for Defining or declaring a vector to be a tensor?

(Also, incidentally, why is the covariant (superscript) index ~nu being displayed as a subscript when Maple echoes my entry?)

Thank you,

Kevin

So, newb question here. I've done my best to debug this line of code, but to no avail. For some reason this function is NOT getting solved correcting for the zeros:

cos(L*x) - x*sin(L*x)

This is not an extremely complex equation either, so I'm at a loss for why my while loop continues to sit there forever. I've got it set to find N number of zeros, but it'll just keep going forever never finding any zeros. I've tried mixing up the start point, and even changed the range which it's searching for them, but nothing seems to get me any closer. Please help!

> restart; with(plots);
> a := 0; b := 1/2; N := 5; w := 1; L := b-a;

Eigenvalue equation
> w := cos(L*x)-sin(L*x)*x;
> plot(w, x = 0 .. 50);

> lam := array(0 .. N+1);

> nn := 0; kk := 5; while nn < N do zz := fsolve(w(x) = 0, x = kk .. kk+1); if type(zz, float) then printf("lam(%d)=%f\n", nn, zz); lam[nn] := zz; nn := nn+1 end if; kk := kk+1 end do

I have an expression of the following structure (the real case is much more complicate but this will illustrate):

expr:=(a+q)*A+b*q*B;

I am looking for a way to change only the first occurrence of q. In my specific case, q << a so I can approximate that instance of q with 0. This I cannot do for the second occurrence of q. Note that the trivial subs(a+q=a) does not work for my real case as a is too complicated (meaning that while in principle I can do it, it looks extremely messy and in any case would not be general).

I can probably concoct something using op(#,expr) and has, but I am wondering whether there is an easier and faster way.

TIA,

Mac Dude

How would I write a function that produces true if a vector/ line satisfies 3 linear inequalities and false if it does not satisfy all 3 linear inequalities? Ie
If the vector <m,n> satisfies ax+by+c>0, dx+ey+f>0 and gx+hy+i>0 then the function returns true, and if it does not satisfy one or more then it returns false? Thanks very much for your time.

I'm trying to use the CriticalPoints command from the Student[Calculus1] package to determine the critical points of f(x) = x^2 * ln(x).

My issue is this. A critical point is defined as a value of x in the domain of f(x) where either f'(x)=0 or f'(x) does not exist. Clearly x=0 is not in the domain of f(x) = x^2*ln(x). How may I "trick" Maple into returning only the value exp(-1/2)?  As seen above, my attempt to use the assuming command proved futile.

More troubling, however, is whether or not the CriticalPoints command is using the correct definition to compute critical points. Can anyone shed some light on this?

Download critpts.mw

Can someone explain to me, if you can, how the Euler angles on the plot interface work?

It looks like Phi is the rotation around z, Theta is the rotation around x, and Psi is around y. I'm trying to use matrices to compute the vector that is pointing towards your face as you're looking at the plot with the given Euler angles.

X := Matrix(3, 3, {(1, 1) = 1, (1, 2) = 0, (1, 3) = 0, (2, 1) = 0, (2, 2) = cos(phi), (2, 3) = sin(phi), (3, 1) = 0, (3, 2) = -sin(phi), (3, 3) = cos(phi)});

Y := Matrix(3, 3, {(1, 1) = cos(theta), (1, 2) = 0, (1, 3) = sin(theta), (2, 1) = 0, (2, 2) = 1, (2, 3) = 0, (3, 1) = -sin(theta), (3, 2) = 0, (3, 3) = cos(theta)});

Z := Matrix(3, 3, {(1, 1) = cos(psi), (1, 2) = sin(psi), (1, 3) = 0, (2, 1) = -sin(psi), (2, 2) = cos(psi), (2, 3) = 0, (3, 1) = 0, (3, 2) = 0, (3, 3) = 1});

and computing X*Y*Z*e3

TIA!

How do I define a function from a graph in a plot? 

Or how do I find the intersection between two lines? I have to find the intersection of 2 lines in a graph, while one of these lines consists of 2 different equations dependent from the same variable. 

Thanks in advance.