MaplePrimes Questions

Note: I would -prefer an answer for Maple 2015, but I can accommodate an answer for a more recent version.

I have a function Gpdf from IR2 to IR+ of class C1 (this comes from the way this function is built).
Although its level curves are continuous, their display show discontinuities for some level values. 

The reason is that  Gpdf contains a term whose denominator vanishes and so, even if the left and right limits of Gpdf are the same at the vanishing point, the resulting plot is dicontinuous.

More details are given in the attached file Discontinuous_contours.mw.

I have tried to adjust the plotting grid, or even to superimpose contours drawn in domains containing no singularities, but I wasn't capable to get continuous drawings (see the attached file).

Do you have any idea to achieve this?

TIA

Hi!

I have M number of linear differential equations. I have solved this system using the 1,2,3,4 stag RK method in the attached file but did not find a significant difference in the accuracy. Kindly see what's wrong there. 

Thank you!

s-stage.mw

When printing a Maple Worksheet  often I go in the PrintPrewiev of the Mac and then select some sides to print.

This is not working anymore since I have updated from Maple 2021 to Maple 2023.

Is this known ?

Any help for his ?

I was trying to assign a Vector to a Vector inside a procedure. However, when the Vector has a size of 5, I was able to do that. But not when the Vector has a size of 7.

I have the following example. I can't assign the Vector over when the Vector has a size of 7 as shown in oneStep_egcd2.  But I can do that when the size is 5 in oneStep_egcd. Copying the contents over using a for loop works as expected. 

 

a:= 17; b:= 5;

17

 

5

(1)

 

# <s, a, t, b, g>
prev := <1, a, 0, b, a>;

Vector(5, {(1) = 1, (2) = 17, (3) = 0, (4) = 5, (5) = 17})

(2)

curr := <0, a, 1, b, b>;

Vector(5, {(1) = 0, (2) = 17, (3) = 1, (4) = 5, (5) = 5})

(3)

oneStep_egcd := proc(prev::Vector, curr::Vector)
    local q, t1, t2, t3;
    if (curr[5] <> 0) then
        q := iquo(prev[5], curr[5]);
        t1, t2, t3 := prev[1] - curr[1] * q, prev[3] - curr[3] * q, prev[5] - curr[5] * q;
        prev = curr;
        curr[1], curr[3], curr[5] := t1, t2, t3;
    end if:
end proc:

oneStep_egcd(prev, curr)

1, -3, 2

(4)

NULL

NULL

# <s, expr_s, a, t, expr_t, b, g>
prev := <1, 1, a, 0, 0, b, a>;

Vector(7, {(1) = 1, (2) = 1, (3) = 17, (4) = 0, (5) = 0, (6) = 5, (7) = 17})

(5)

curr := <0, 0, a, 1, 1, b, b>;

Vector(7, {(1) = 0, (2) = 0, (3) = 17, (4) = 1, (5) = 1, (6) = 5, (7) = 5})

(6)

oneStep_egcd2 := proc(prev::Vector, curr::Vector)
    local q, sb_q, t1, t2, t4, t5, t7;
    if (curr[7] <> 0) then
        q := iquo(prev[7], curr[7]);
        sb_q := (q);
        t1 := prev[1] - curr[1] * q;
        t2 := prev[2] - curr[2] * q;
        t4 := prev[4] - curr[4] * q;
        t5 := prev[5] - curr[5] * q;
        t7 := prev[7] - curr[7] * q;
        prev := curr;
        curr[1], curr[2], curr[4], curr[5], curr[7] := t1, t2, t4, t5, t7;
    end if:
end proc:

oneStep_egcd2(prev, curr)

Error, (in oneStep_egcd2) invalid left hand side in assignment

 

NULL

oneStep_egcd3 := proc(prev::Vector, curr::Vector)
    local q, sb_q, t1, t2, t4, t5, t7, i;
    if (curr[7] <> 0) then
        q := iquo(prev[7], curr[7]);
        sb_q := (q);
        t1 := prev[1] - curr[1] * q;
        t2 := prev[2] - curr[2] * q;
        t4 := prev[4] - curr[4] * q;
        t5 := prev[5] - curr[5] * q;
        t7 := prev[7] - curr[7] * q;
        for i to 7 do
            prev[i] := curr[i];
        end do;
        curr[1], curr[2], curr[4], curr[5], curr[7] := t1, t2, t4, t5, t7;
    end if:
end proc:

oneStep_egcd3(prev, curr)

1, 1, -3, -3, 2

(7)

NULL

Download ErrorExample.mw

Hello

I want to write a program to get unknown coefficients of multiple polynomials. I have a problem with this program. The code sometimes doesn't work. Can anyone help me? It's very important to me.

restart

with(student)

``

EQ[0] := tanh(d)*b[1]*(b[1]+1)

tanh(d)*b[1]*(b[1]+1)

(1)

EQ[1] := -(-1+(a[1]-b[1]-1)*tanh(d)^2+(a[0]+1)*tanh(d))*b[1]

-(-1+(a[1]-b[1]-1)*tanh(d)^2+(a[0]+1)*tanh(d))*b[1]

(2)

EQ[2] := tanh(d)*((a[1]-b[1])*(a[0]+1)*tanh(d)-b[1]^2-a[1])

tanh(d)*((a[1]-b[1])*(a[0]+1)*tanh(d)-b[1]^2-a[1])

(3)

EQ[3] := (-a[1]^2+(2*b[1]-1)*a[1]-b[1]^2-b[1])*tanh(d)^2+(a[1]+b[1])*(a[0]+1)*tanh(d)-a[1]-b[1]

(-a[1]^2+(2*b[1]-1)*a[1]-b[1]^2-b[1])*tanh(d)^2+(a[1]+b[1])*(a[0]+1)*tanh(d)-a[1]-b[1]

(4)

EQ[4] := -tanh(d)*((a[1]-b[1])*(a[0]+1)*tanh(d)+a[1]^2+b[1])

-tanh(d)*((a[1]-b[1])*(a[0]+1)*tanh(d)+a[1]^2+b[1])

(5)

EQ[5] := -a[1]*(-1+(-a[1]+b[1]-1)*tanh(d)^2+(a[0]+1)*tanh(d))

-a[1]*(-1+(-a[1]+b[1]-1)*tanh(d)^2+(a[0]+1)*tanh(d))

(6)

EQ[6] := (a[1]+1)*a[1]*tanh(d)

(a[1]+1)*a[1]*tanh(d)

(7)

Eqs := {seq(EQ[i], i = 0 .. 6)}

Sol := solve(Eqs, {a[0], a[1], b[1]})NULL

{a[0] = a[0], a[1] = 0, b[1] = 0}, {a[0] = (tanh(d)^2-tanh(d)+1)/tanh(d), a[1] = -1, b[1] = -1}, {a[0] = -(tanh(d)-1)/tanh(d), a[1] = -1, b[1] = 0}, {a[0] = -(tanh(d)-1)/tanh(d), a[1] = 0, b[1] = -1}

(8)

for i from 2 to 4 do Case[i] := allvalues(Sol[i]) end do

{a[0] = -(tanh(d)-1)/tanh(d), a[1] = 0, b[1] = -1}

(9)

``

T1.mw

T2.mw

My Maple-Program is creating svg-files (or PNG) in a squared format.
There are a lot of these files in a local folder.
I would like to add a white surrounding frame (10% of the Imagesize) to it and afterwards store it as a TIFF file.

Studying ImageTools I have not found a way to solve this with ImageTools.

Until now I am using a graphic software to add a frame and store as TIFF in a desired resolution.

Now I plan to do this process automatically with maple.

Thanks for support :)

I found this option mentioned in help(MapleSim,Multibody,Dynamic_Exports).

For the example of the help page I tried

SliderCrank:-GetDynEQs(AugType = Reaction);
SliderCrank:-GetDynEQs(AugType = Lagrange);

but the output is the same (which I would expect since GetDynEQs is not defined with parameters).

In the help system I only find deprecated commands that use this option

How can this option be set in newer versions of MapleSim without using deprecated commands?

For the following Equation:

Equation := int(diff(u(x), x)*v(x), x) = int(u(x)^(1/2)*v(x), x)^(-2/3);
Maplesoft finds the following solution:

Solution1:=3/4*u(x)^(4/3) + 2/3*u(x)^(5/6)*Intat(1/(sqrt(u(x))*Int(v(_b), _b))^(5/3), _b = x) + _C1 = 0

or , which I believe as an alternative, can be written as

Solution2:=3/4*u(x)^(4/3) + 2/3*u(x)^(5/6)*Int(1/(sqrt(u(x))*Int(v(x),x))^(5/3) +_C1=0

My question is how did Maple arrive at 'Solution1' from 'Equation'? In other words, can someone fill

in the steps between 'Equation'  and 'Solution1'? Or even, prove that Solution 1 is a valid solution to Equation.

Plugging the Solution1 into Equation, did not clearly demonstate the validity of the solution (to me at least)

Unfortunately, I am still unable to post the corresponding Maplesoft worksheet onto this post.

Invoked by the OEIS superseeker, Maple "gfun" package "listtoalgeq" identified possible lgdegf for https://oeis.org/A035001

1, 2, 4, 5, 8, 12, 14, 16, 28, 32, 37, 64, 94, 106, 128, 144, 232, 256, 289, 320, 512, 560, 704, 760, 838, 1024, 1328, 1536, 1944, 2048, 2329, 3104, 3328, 4096, 4864, 6266, 6802, 7168, 8192, 11952, 15360, 16384, 16428, 19149, 28928, 32768, 37120, 42168 

as follows:

1024-5120*a(n)+11520*a(n)^2-15360*a(n)^3+13440*a(n)^4-8064*a(n)^5+3360*a(n)^6-960*a(n)^7+180*a(n)^8-20*a(n)^9+a(n)^{10}

The coefficients of above polynomial are:

{1, -20, 180, -960, 3360, -8064,13440, -15360, 11520, -5120, 1024,...}

It is interesting that the absolute values of above polynomial coefficients satisfy a(n) of

https://oeis.org/A013609

for n=55...65,

which is the 11th row in the triangle presentation of A013609, so in other words the absolute values of above polynomial coefficients are T={11, k} for k=1...11

Dear Users!

I hope you are doing well. I have the following discretized form

for n>=1 and j=0..M. We obtained the following matrix equation for any "n" and j=0..M as:

I want matrix proc of any useful way to define A^n, u^n, and b^n. I am waiting for your positive response. Thanks in advancs

I would like to do some point and line calculations, and the geom3d package seems a good one.

But how do I define a generic point such that I can use it in a function to generate genric points and lines?

eg

    P:=(a,b,c)->point(P, a,b,c) 

or equivalent?

I would then want to define generic lines between generic points.

Consider the following. 

We have a matrix A with five parameters in it.

If we tell Maple to solve Ax=0, it gives us the trivial solution.

Then, if I make a matrix B where I choose specific values for those five parameters and I tell Maple to solve Bx=0 I get a non-trivial solution.

Why doesn't Maple give me a more informative result in the Ax=0 case? 

A := Matrix(5, 5, {(1, 1) = 1, (1, 2) = 0, (1, 3) = 0, (1, 4) = 0, (1, 5) = a__1, (2, 1) = 0, (2, 2) = 1, (2, 3) = 0, (2, 4) = 0, (2, 5) = b__1, (3, 1) = -216, (3, 2) = -18, (3, 3) = 0, (3, 4) = 0, (3, 5) = c__1, (4, 1) = 0, (4, 2) = 0, (4, 3) = 1, (4, 4) = 0, (4, 5) = d__1, (5, 1) = 0, (5, 2) = 0, (5, 3) = 0, (5, 4) = 1, (5, 5) = e__1}) = Matrix(%id = 36893488151959194068)NULL

with(LinearAlgebra)

GaussianElimination(A)

Matrix(%id = 36893488151959184316)

(1)

LinearSolve(A, `<,>`(0, 0, 0, 0, 0))

Vector[column](%id = 36893488151959183100)

(2)

B := Matrix(5, 5, {(1, 1) = 1, (1, 2) = 0, (1, 3) = 0, (1, 4) = 0, (1, 5) = 0, (2, 1) = 0, (2, 2) = 1, (2, 3) = 0, (2, 4) = 0, (2, 5) = 0, (3, 1) = -216, (3, 2) = -18, (3, 3) = 0, (3, 4) = 0, (3, 5) = 0, (4, 1) = 0, (4, 2) = 0, (4, 3) = 1, (4, 4) = 0, (4, 5) = 1, (5, 1) = 0, (5, 2) = 0, (5, 3) = 0, (5, 4) = 1, (5, 5) = 4}) = Matrix([[1, 0, 0, 0, 0], [0, 1, 0, 0, 0], [-216, -18, 0, 0, 0], [0, 0, 1, 0, 1], [0, 0, 0, 1, 4]])NULL

GaussianElimination(B) = Matrix(%id = 36893488151959174788)NULL

LinearSolve(B, `<,>`(0, 0, 0, 0, 0))

Vector[column](%id = 36893488151959164916)

(3)

``

NULL

An even easier way to show a non-trivial solution is to just make the entire last column zero.

Download polyn_matrix.mw

Dear all 

I have a function defined on many sub-intervals, how can I simplify this the funciton obtained at each iteration. I hope obatin B_{i,1}, B_{i,2}, and B_{i,3} 

B_Spline.mw

Thank you 

Dear Users!

I hope everyone is fine here. I have three vectors say V[1], V[2] and V[3] as:

restart; with(LinearAlgebra); with(linalg);
V[1] := Vector([3, 2, -4]);
V[2] := Vector([1, 2/3, 7]);
V[3] := Vector([-9, 0, 1/2]);

I can define a Vector V have V[1], V[2] and V[3] using blockmatrix command as:

C := blockmatrix(3, 1, [V[1], V[2], V[3]]);

My question is that how I can extract vectors V[1], V[2] and V[3] from C? Thanks in advance

Is there a simple 4-vector package available for Maple? Yes, I know about using Tensors, but don't want to fool with metrics and raising and lowering operators.

I have written my  own, but it seems buggy. I generate some vectors in in CM that should add up to a massless neutrino, but some times when I boost them to the 'lab' and do the addition there the neutrion acquires a substantial mass. It's not a merely numerical issue. It's weird because most of the time the neutrion mass is 0 or close to it.

My homemade boost proc 'boostTo' is attached.

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