I've got the following:

Integral_over_region.mw

M_Iwaniuk

I should be able to use F3 to break into a multline nested loop and insert a new line of code, and then F4 to close it up again before execution.  The F4 works for closing things up.  But the F3 does NOT work.  Is this a known problem?  Is there another way to do it short of a lot of cutting and pasting?

I created a regular 2D without specifying the number of points. I tried to change its style from "line" to "point", but i cannot see the symbols because there are too many points and so all i see is a thick black line. Is replotting with less points the only way, or can I interactively reduce the number of points? 

I just bought 2016 Maple. For a few days, everything was fine.

The increase of the speed calculations is very significant.

Then copy and paste gave unexpected results: impossible to keep the symbols, systematic conversion in text,in mode MathML,, appearance of ASCII characters in the texts, etc ..

all attempts to change the settings have failed

I spend more time correcting the changes that occur in the copy and paste that to take care of my equations.

Do you have an explanation ?

Hello everyone!

Is this a bug that the following two commands work differently?:

densityplot(sin(x*y), x = -5 .. 5, y = -5 .. 5, colorscheme = ["zgradient", ["blue", "green", "yellow", "red"], zrange = -5 .. 5], style = surface)

plot3d(sin(x*y), x = -5 .. 5, y = -5 .. 5, view = -10 .. 10, colorscheme = ["zgradient", ["blue", "green", "yellow", "red"], zrange = -5 .. 5], style = surface)

The second one works fine in that if you increase the magnitude of sin(x*y) (e.g. 3sin(x*y)) the coloring changes accordingly. But the first one plots sin(x*y) or 5sin(x*y), etc. just the same!

Many thanks for you comments in advance!

Dear Maple researchers

I have a problem in solving a system of odes that resulted from discretizing, in space variable, method of lines (MOL).

The basic idea of this code is constructed from the following paper:

http://www.sciencedirect.com/science/article/pii/S0096300313008060

If kindly is possible, please tell me whas the solution of this problem.

With kin dregards,

Emran Tohidi.

My codes is here:

> restart;
> with(orthopoly);
print(`output redirected...`); # input placeholder
> N := 4; Digits := 20;
print(`output redirected...`); # input placeholder

> A := -1; B := 1; rho := 3/4;
> g1 := proc (t) options operator, arrow; 1/2+(1/2)*tanh((1/2)*(A-(2*rho-1)*t/sqrt(2))/sqrt(2)) end proc; g2 := proc (t) options operator, arrow; 1/2+(1/2)*tanh((1/2)*(B-(2*rho-1)*t/sqrt(2))/sqrt(2)) end proc;
print(`output redirected...`); # input placeholder
> f := proc (x) options operator, arrow; 1/2+(1/2)*tanh((1/2)*x/sqrt(2)) end proc;
print(`output redirected...`); # input placeholder
> uexact := proc (x, t) options operator, arrow; 1/2+(1/2)*tanh((1/2)*(x-(2*rho-1)*t/sqrt(2))/sqrt(2)) end proc;
print(`output redirected...`); # input placeholder
> basiceq := simplify(diff(uexact(x, t), `$`(t, 1))-(diff(uexact(x, t), `$`(x, 2)))+uexact(x, t)*(1-uexact(x, t))*(rho-uexact(x, t)));
print(`output redirected...`); # input placeholder
                                      0
> alpha := 0; beta := 0; pol := P(N-1, alpha+1, beta+1, x); pol := unapply(pol, x); dpol := simplify(diff(pol(x), x)); dpol := unapply(dpol, x);
print(`output redirected...`); # input placeholder
> nodes := fsolve(P(N-1, alpha+1, beta+1, x));
%;
> xx[0] := -1;
> for i to N-1 do xx[i] := nodes[i] end do;
print(`output redirected...`); # input placeholder
> xx[N] := 1;
> for k from 0 to N do h[k] := 2^(alpha+beta+1)*GAMMA(k+alpha+1)*GAMMA(k+beta+1)/((2*k+alpha+beta+1)*GAMMA(k+1)*GAMMA(k+alpha+beta+1)) end do;
print(`output redirected...`); # input placeholder
> w[0] := 2^(alpha+beta+1)*(beta+1)*GAMMA(beta+1)^2*GAMMA(N)*GAMMA(N+alpha+1)/(GAMMA(N+beta+1)*GAMMA(N+alpha+beta+2));
print(`output redirected...`); # input placeholder
> for jj to N-1 do w[jj] := 2^(alpha+beta+3)*GAMMA(N+alpha+1)*GAMMA(N+beta+1)/((1-xx[jj]^2)^2*dpol(xx[jj])^2*factorial(N-1)*GAMMA(N+alpha+beta+2)) end do;
print(`output redirected...`); # input placeholder
> w[N] := 2^(alpha+beta+1)*(alpha+1)*GAMMA(alpha+1)^2*GAMMA(N)*GAMMA(N+beta+1)/(GAMMA(N+alpha+1)*GAMMA(N+alpha+beta+2));
print(`output redirected...`); # input placeholder
> for j from 0 to N do dpoly1[j] := simplify(diff(P(j, alpha, beta, x), `$`(x, 1))); dpoly1[j] := unapply(dpoly1[j], x); dpoly2[j] := simplify(diff(P(j, alpha, beta, x), `$`(x, 2))); dpoly2[j] := unapply(dpoly2[j], x) end do;
print(`output redirected...`); # input placeholder
print(??); # input placeholder
> for n to N-1 do for i from 0 to N do BB[n, i] := sum(P(jjj, alpha, beta, xx[jjj])*dpoly2[jjj](xx[n])*w[i]/h[jjj], jjj = 0 .. N) end do end do;
> for n to N-1 do d[n] := BB[n, 0]*g1(t)+BB[n, N]*g2(t); d[n] := unapply(d[n], t) end do;
print(`output redirected...`); # input placeholder
> for nn to N-1 do F[nn] := simplify(sum(BB[nn, ii]*u[ii](t), ii = 1 .. N-1)+u[nn](t)*(1-u[nn](t))*(rho-u[nn](t))+d[nn](t)); F[nn] := unapply(F[nn], t) end do;
print(`output redirected...`); # input placeholder
> sys1 := [seq(d*u[q](t)/dt = F[q](t), q = 1 .. N-1)];
print(`output redirected...`); # input placeholder
[d u[1](t)                                                                
[--------- = 40.708333333333333334 u[1](t) + 52.190476190476190476 u[2](t)
[   dt                                                                    

                                                                  2          3
   + 39.958333333333333334 u[3](t) - 1.7500000000000000000 u[1](t)  + u[1](t)

   + 7.3392857142857142858

   - 3.6696428571428571429 tanh(0.35355339059327376220

   + 0.12500000000000000000 t) - 3.6696428571428571429 tanh(
                                                     d u[2](t)   
-0.35355339059327376220 + 0.12500000000000000000 t), --------- =
                                                        dt       
-20.416666666666666667 u[1](t) - 25.916666666666666667 u[2](t)

                                                                  2          3
   - 20.416666666666666667 u[3](t) - 1.7500000000000000000 u[2](t)  + u[2](t)

   - 3.7500000000000000000

   + 1.8750000000000000000 tanh(0.35355339059327376220

   + 0.12500000000000000000 t) + 1.8750000000000000000 tanh(
                                                     d u[3](t)                
-0.35355339059327376220 + 0.12500000000000000000 t), --------- = 29.458333333\
                                                        dt                    

  333333333 u[1](t) + 38.476190476190476190 u[2](t)

                                                                  2          3
   + 30.208333333333333333 u[3](t) - 1.7500000000000000000 u[3](t)  + u[3](t)

   + 5.4107142857142857144

   - 2.7053571428571428572 tanh(0.35355339059327376220

   + 0.12500000000000000000 t) - 2.7053571428571428572 tanh(
                                                   ]
-0.35355339059327376220 + 0.12500000000000000000 t)]
                                                   ]
> ics := seq(u[qq](0) = evalf(f(xx[qq])), qq = 1 .. N-1);
print(`output redirected...`); # input placeholder
    u[1](0) = 0.38629570659055483825, u[2](0) = 0.50000000000000000000,

      u[3](0) = 0.61370429340944516175
> dsolve([sys1, ics], numeic);
%;
Error, (in dsolve) invalid input: `PDEtools/sdsolve` expects its 1st argument, SYS, to be of type {set({`<>`, `=`, algebraic}), list({`<>`, `=`, algebraic})}, but received [[d*u[1](t)/dt = (20354166666666666667/500000000000000000)*u[1](t)+(13047619047619047619/250000000000000000)*u[2](t)+(19979166666666666667/500000000000000000)*u[3](t)-(7/4)*u[1](t)^2+u[1](t)^3+36696428571428571429/5000000000000000000-(36696428571428571429/10000000000000000000)*tanh(1767766952966368811/5000000000000000000+(1/8)*t)-(36696428571428571429/10000000000000000000)*tanh(-1767766952966368811/5000000000000000000+(1/8)*t), d*u[2](t)/dt = -(20416666666666666667/1000000...

I have the following problem : plotting with the squareroot function somehow stops showing the whole graph as soon as the range of the input allows values less than -10, I have attached two pictures that show the transition:

This is still fine:

But here is an example where the graph is cropped:

How can I change this to get the whole graph ? Thanks a lot for your help !!

Is there a Maple function that given a set of substitutions in form object=set of substitute objects produces a sequence of sets, each a product of substitution from the next, remove repetitions. An example:

Hi I'm not really sure how to phrase this but I'm doing projectile motion and I'm try to graph the solutions for v_0 by theta_0.

According to Sphere Packing Solved in Higher Dimensions, the best way, i.e., most compact way, to pack spheres in dimensions 8 and 24 are done with the E8 lattice and Leech lattice, respectively. According to the Wikipedia article Leech lattice, the number of spheres that can be packed around any one sphere is 240 and 196,560 (!), respectively, the latter number of spheres counter-intuitively large. It inspired me to try to check that there is indeed room in these lattices for (at least) this number of spheres.

Starting with the E8 lattice: It is generated by the sum (over the integers) of all the 240 roots of E8. Following the prescription given in the subsection 'Construction' in the Wikipedia article E₈ (mathematics), these roots may be constructed as follows:

ROOTS := map(x -> Vector(x),[
   # Coordinates all integers: 112 roots
   combinat[permute]([+1,+1,0,0,0,0,0,0])[],
   combinat[permute]([+1,-1,0,0,0,0,0,0])[],
   combinat[permute]([-1,-1,0,0,0,0,0,0])[],
   # Coordinates all half-integers: 128 roots
   seq(combinat[permute]([
      (+1/2)$(  2*n),   # Even number of +1/2
      (-1/2)$(8-2*n)    # Even number of -1/2
   ])[],n = 0..4)
]):

This Maple code gives a list of 240 eight-dimensional vectors. All these roots have the same length (the lattice thus being simply laced):

convert(map(x -> Norm(x,2),ROOTS),set)[];

If the distance between any pair of different roots is at least this length, then there will be room for 240 spheres of radius equal to this length around any one single sphere. And that is indeed the case:

DIST_ROOTS := Matrix(nops(ROOTS)$2,(i,j) ->
   Norm(ROOTS[i] - ROOTS[j],2)
,shape = symmetric):
min(convert(DIST_ROOTS,set) minus {0});

Using the above method for the Leech lattice will fail on grounds of hopeless performance, not the least because DIST_ROOTS will take ages to calculate, if at all possible. So any reader is welcome to weigh in with ideas on how to check the Leech lattice case.

PS: By the way, I was surprised to find that the three exceptional Lie algebras E6, E7, and E8 are seemingly not accessible through the Maple command SimpleLieAlgebraData, see its help page. Only the four infinite families A,B,C,D, as well as the two exceptional Lie algebras G2 and F4 are. Using Maple 17, I would like to know if that has been changed in Maple 17+, and if not, why not.

hi .why matrix a dont create?

bot.mw

Download bot.mw

I want to solve system of non linear odes numerically.

I encounter following error

Error, (in dsolve/numeric/bvp) cannot determine a suitable initial profile, please specify an approximate initial solution

how to correct it

regards

In workbook mode I use the Insert>>Paragaph>>Before Cursor to create a text block. I just want to type text into this block by way of comments on what preceded/follows. However, when I type parentheses or <> of (I expect) other stuff that Maple recognises as being parts of mathematical expressions Maple switches to italic and bold and starts generally interefering with my text. In the case of my title I get the result in the picture below. Is there any way to stop Maple doing this so I can type text?

How I can solve it ? If I want a solution dependent of a. With fsolve? But how?

-x³+ax²-lnx=0
 

Hello,

I'm working in a project where I use the Java Open Maple library. I need to evaluate a procedure but with a very large number. In the function engine.newNumeric() the only large option is a long which is not enough for me. I use Java BigInteger class to represent my very large numbers. Any suggestions that might help is very welcomed!

Thank you