Hi Dears,

I'm have a code like this:

sum(-GAMMA(k+1, x), k = 0 .. -2) and Maple give me : Ei(1, x).

How to check that answer is correct?

Thank you in advance.

I am looking forward to hearing from you.

Hi, i try resolve this equations numerical for the boundary between the spinglass and ferromagnetic phases:

how?

Regards.

Sudoku is a well known Latin square type game, see https://en.wikipedia.org/wiki/Sudoku

Here is a Sudoku game and its (unique) solution:

A,Sol:=  # A = Sudoku matrix, 0 for each empty cell
Matrix(9, [
[0,0,3,0,9,0,1,0,0],
[0,5,0,3,0,0,7,0,0],
[1,0,2,0,0,5,0,6,4],
[0,1,0,0,2,0,9,0,0],
[2,0,0,6,0,3,0,0,1],
[0,0,7,0,8,0,0,3,0],
[7,6,0,9,0,0,8,0,5],
[0,0,8,0,0,7,0,9,0],
[0,0,4,0,6,0,2,0,0]]),
Matrix(9, [
[4,7,3,2,9,6,1,5,8],
[8,5,6,3,4,1,7,2,9],
[1,9,2,8,7,5,3,6,4],
[3,1,5,7,2,4,9,8,6],
[2,8,9,6,5,3,4,7,1],
[6,4,7,1,8,9,5,3,2],
[7,6,1,9,3,2,8,4,5],
[5,2,8,4,1,7,6,9,3],
[9,3,4,5,6,8,2,1,7]]);

The procedure which follows is a very compact Sudoku solver. It uses Groebner bases. I hope that you will like it.
The input is the Sudoku matrix and the solution matrix is returned.
Note that the Sudoku matrix must be valid and must have a unique solution.
(Otherwise, theoretically, the error "Invalid Sudoku matrix" should appear.)
Note also that the procedure may be very slow for some games or Maple may crash. This happened to me once with a very "hard" matrix.

I was impressed that Maple's implementation for Groebner bases works now so well for this problem!

A few years ago on this site: http://www.mapleprimes.com/questions/131939-Calculating-Groebner-Basis-For-Sudoku
it was an attempt to solve the problem with this method but it failed (due to wrong number of polynomials).

sudoku:=proc(A::'Matrix'(9,integer))
local x_A,x,Q,R,r, i,j,u,v,G;
Q:=proc(X,Y) normal((mul(X-i,i=1..9)-mul(Y-i,i=1..9))/(X-Y)) end;
x_A:=seq(seq( `if`(A[i,j]>0,x[i,j]-A[i,j],NULL),i=1..9),j=1..9);
R:={seq({seq(x[i,j],j=1..9)},i=1..9), seq({seq(x[i,j],i=1..9)},j=1..9),
    seq(seq({seq(seq(x[3*u+i,3*v+j],i=1..3),j=1..3)},u=0..2),v=0..2)};
G:=Groebner:-Basis({seq(seq(seq(Q(u,v),u=r minus {v}),v=r),r=R),x_A},'_vv');
if nops(G)<>81 then error "Invalid Sudoku matrix" fi;
eval(Matrix(9,symbol=x), `union`(map(u->solve({u}), G)[]));
end:

sudoku(A) < A; # Solving the previous game

# Let's solve another one:
A:=Matrix(9,9,[[0,0,0,4,0,0,0,8,0],[0,5,2,7,0,0,4,0,0],[3,0,0,0,0,0,0,0,0],[5,1,0,8,0,0,0,0,0],[0,0,0,5,0,0,6,7,0],[0,9,0,0,7,0,0,0,3],[2,4,0,0,0,5,0,0,0],[9,0,0,0,0,0,0,3,8],[0,0,0,0,0,0,9,4,0]]):
sudoku(A) < A;

Matrix   # A Sudoku matrix which crashes Maple!
(9,[[8,0,0,0,0,0,0,0,0],[0,0,3,6,0,0,0,0,0],[0,7,0,0,9,0,2,0,0],[0,5,0,0,0,7,0,0,0],[0,0,0,0,4,5,7,0,0],[0,0,0,1,0,0,0,3,0],[0,0,1,0,0,0,0,6,8],[0,0,8,5,0,0,0,1,0],[0,9,0,0,0,0,4,0,0]]):

Hi

I have the ODEs: x'=x

ode:=diff(x(t),t)-x(t);

sketch the phase space and extended phase space of previous ode.

theta := a-(1/2)*beta*a*y^2+(1/24)*beta^2*a*y^4-(1/720)*beta^3*a*y^6+(1/40320)*beta^4*a*y^8-(1/3628800)*beta^5*a*y^10+(1/479001600)*beta^6*a*y^12-(1/87178291200)*beta^7*a*y^14+(1/20922789888000)*beta^8*a*y^16-(1/6402373705728000)*beta^9*a*y^18+(1/2432902008176640000)*beta^10*a*y^20-(1/1124000727777607680000)*beta^11*a*y^22+(1/620448401733239439360000)*beta^12*a*y^24

Pls, anyone with useful informations on how to convert a series just like the one above to trigonometry or hyperbolic form. Need response as soon as possible. Thankin you in anticipation for your favorable response. 

hello,I want to solve a quesstion about heat equation,that the quesstion like this:

I use the code like this

but the results is wrong obviously and what's wrong with this code?

anxious for your help,thanks.

hi

how can i plot a 3d polygonal cylinder for example a hexagonal?

Hi

Any help will be appreciated

I have a continuous time dynamical system

x in R ( set of real number)

t  a positive real time

and the function f_t(x)=x-t

How can we plot or sketch their behaviour in the phase space and in the extended phase space

Many thanks

Hello Guys,

I am having a problem plotting a graph from some sets of point. Please how do I plot a graph having some set of point.

Thanks. 

Dear friends:

I am facing to search the command which zoom a sactor of graph, I know it can be done by using maple tools whose present tool bar but I need a command for zooming please help me to fix this problem (attached) I want to see th sactor eta=0.8 to eta=1.2.

graph_phi_varies.mw

Please see the problem and correct as soon as possible. I am waiting your positive respone.

Muhammad Usman

School of Mathematical Sciences 
Peking University, Beijing, China

The distance from the point to the surface easily calculated using the NLPSolve of Optimization package. If the point is not special, we will find for it a point on the surface, the distance between these two points is the shortest between the selected point and the surface.
Two examples:  the implicit surface and the parametric surface.
To test, we restore the normals from the  calculated  points (red) by using analytical equations.
DISTANCE_TO_SURFACE.mw

A man walks to different points.

I have to find the point that has a minimal length.
Perhaps through the Repetition Statement (for...while...do)

For the space curve in the linked worksheet, RadiusOfCurvature and Binormal give incorrect results. Why?

TNB_anomalies.mw

Please tell me if the above link doesn't work.

I have a function which calculates a number for [x,y] inside a matrix, which depends on the values surrounding said initial cell (from [x-1,y-1] yo [x+1,y+1]). However, for the values on the border, the idea is to go around to the opposite side, creating a Torus of the sort.
The solution I seemed to have found was to create 4 indices: 2 controled with 'for' and 2 which were modified accordingly to be used as imputs for the function:

x:=x0;y:=y0;
for r from x-1 to x+1 do
    print("r",r);
    for t from y-1 to y+1 do
        print("t",t);
        if r=0 then i:=N; else i:=r; fi;
        if t=0 then j:=N; else j:=t; fi;
        if r=N+1 then i:=1; else i:=r; fi;
        if t=N+1 then j:=1; else j:=t; fi;
        print("i",i);print("j",j);
        function(i,j);
od; od;
 

(the print commands are for the tests I have been running so see where the potential error lied).
If you run this script, you can clearly see for x0,y0<>1 that it works perfectly, even for x0,y0=N where it succesfully goes around and changes to 1. However, for x0,y0=1 it isn't able to detect that r&t=0 and so it doesn't change it to N; creating an error where it tries to find the value 0 of an Array.

Thanks in advance,
Enrique

how to read a jpg picture and draw mesh on it?

mesh generator in maple

how to get all points and lines from this mesh on jpeg picture?