Hi, I am learning GR and new to maple. I played with maple's DifferentialGeometry package.

While duplicated the maple GR example, in DGsetup([t, r, theta, phi], M1, verbose),

I got the error,

DGsetup([t, r, theta, phi], M1, verbose)

The following coordinates have been protected:
[t, r, theta, phi]

The following vector fields have been defined and protected:

Error, (in Typeset:-Tdisplay[true]) `alias` does not evaluate to a module

 I don't know how to fix it. Can anyone kindly help?

Thanks

I'm trying to build a Maple procedure that will generate vector fields on a metric with certain properties. Working with metric g over the coordinates {u,v,w}, call the field X = (a(u,v,w), b(u,v,w), c(u,v,w)). The field should satisfy <X, X> = 0 and have the directional covariant derivative of X in the direction of each coordinate vector field = 0 (with resepct to the Levi-Civita conenction).

Basically, these conditions yield a system of 3 PDEs and an algebraic expressionin terms of a,b,c. I've been trying to solve them using pdsolve, but I'm getting the error message:

>Error, (in pdsolve/sys) the input system cannot contain equations in the arbitrary parameters alone; found equation depending only on _F1(u,v,w): _F1(u,v,w)

I've attached my worksheet. Can anyone help me out?

Thanks! ppwaves.mw

Here we develop the factoring in common factor, simple and complete square blade, plus simple equation systems with graphic and design, and graphic solution of the quadratic equation using components in maple 2015.

Factorizacion.mw

(in spanish)

L.AraujoC.

Hello,

i am trying to get a latex output which equals the displayed maple equations, where i am using alias/surpress or declare to shorten the dependencies of my derivatives. Whereas in Maple this looks how i want it to look like, i can not get the latex() command to apply the aliases. Instead it replaces the short forms with the long terms before creating the latex code. Is there anyway to get a latex output directly from the displayed math WITH alias?

2 small examples:

Both yield  $ X \left( a,b,c \right)$ whereas i would like to get X. Simply substituing changes the partial differential symbol to "d" in the latex output and makes the equations unuseable, so this is no option i guess..

Thanks a lot for any suggestions!

I have three cylinders as follows.

with(plots);
with(plottools);
p1 := cylinder([1, 1, 1], 1, 1);
p2 := cylinder([1, 1, 1], 2, 3);
p3 := cylinder([1, 1, 1], 1, 4);

I want to display in order where p1 is at the bottom, then p2, and then p3 on the top of p2. Thank you for your assistance.

I have the following PDE system to solve numerically and I am not sure how to use maple to solve it.

v_t = v_{xx} for 0<x<1 , t>0

v(x,0)=1

v_x(1,t)=-hv^4(1,t) (where h is some numerical number);

v_x(0,t)=0

To solve this pde numerically I need to use the following condition on v(1,t):

v(1,t) = 1-h*\int_{0}^t \theta_3(\tau)v(1,t-\tau)^4d\tau

this is the numerical boundary condition, where \theta_3 is Jacobi theta3 function.

I don't see how can I use maple for this numerical pde problem.

Here's my attempt at solution:

[code]

 PDE := diff(v(x, t), t) = diff(v(x, t), x, x);

JACOBIINTEGRAL := int(JacobiTheta3(0, exp(-Pi^2*s))*v(1, t-s)^4, s = 0 .. t);

IBC := {`&PartialD;`(v(0, t))/`&PartialD;`(x) = 0, `&PartialD;`(v(1, t))/`&PartialD;`(x) = -0.65e-4*v(1, t)^4, v(x, 0) = 1};

pds := pdsolve(PDE, IBC, numeric, time = t, range = 0 .. 1, spacestep = 0.1e-2, timestep = 0.1e-2, numericalbcs = {v(1, t) = 1-0.65e-4*JACOBIINTEGRAL}, method = ForwardTimeCenteredSpace)

[/code]

But I get the next error message:

Error, (in pdsolve/numeric/process_IBCs) improper op or subscript selector

How to fix this or suggest me a better way to solve this pde numerically?

Hi EveryOne!

Let matrix M over GF(2ⁿ)/f(x). How to compute:

1. Rank of M.

2. Sum of the elements and Square of this Sum in any row of M (i.e: Sum=m_i0 + m_i1 + ... + m_in, and Sum² ).

3. New matrix M, where in row i  m_i0 = m_i0/Sum², m_i1 = m_i1/Sum², ..., m_in = m_in/Sum².

Please help me. Thank you very much.

Given a polynomial in several variables is it possible to split it so that all the coefficients of the monomials are +1 or -1.

Example:

p:=-z+2*x+4*y-3*x*y.

I would lie to obtain

f:=-z +x+x +y+y+y+y -x*y-x*y-x*y.

Given a polynomial expression I would like to obtain a list whose entries are the positive entries of the polynomial with multiplicity given by the coefficients:

Example:

Given the polynomial expression: p:=x^2*y-2*y*z+3*x^2+2*y-z

The positive terms are: x^2*y, 3*x^2, 2*y

Thus I would like to obtain the list L:=[x^2*y , x^2 , x^2 , x^2, y , y].

Notice x^2*y appears once since the coefficient is 1.

x^2 appears three times since the coefficient is 3.

y appears two times since the coefficient is 2.

Is there a way to divide two lists entry by entry. I mean the following:

L:=[2,4,6,3];

T:=[2,2,3,1];

L/T=[1,2,2,3]

Given a list I would like to find the position of the positive numbers. Ex: Given L:=[3,8,-5,1,-3,-7], I would like to have as a result P:=[1,2,4].

I want to avoid using a loop for this. Any suggestion?

Hello,

I need to solve the next ode:

diff(u(x, y), x) = -(2/3)*(3*h^3*nu+9*h^2*nu*y-12*nu*y^3+36*x^2*y+56*y^3)/h^3

diff(v(x, y), y) = (2/3)*(36*nu*x^2*y+56*nu*y^3+3*h^3+9*h^2*y-12*y^3)/h^3

diff(u(x, y), y)+diff(v(x, y), x) = -(6*(1+nu))*x*(h^2-4*y^2)/h^3

The inicial conditions are:

u(L, 0) = 0
v(L, 0) = 0
D[1]*u(L, 0) = 0

When I write on Maple this code, he give me a error:

with(PDEtools, casesplit, declare); declare((u, v)(x, y))

sys2 := [diff(u(x, y), x) = -(2/3)*(3*h^3*nu+9*h^2*nu*y-12*nu*y^3+36*x^2*y+56*y^3)/h^3, diff(v(x, y), y) = (2/3)*(36*nu*x^2*y+56*nu*y^3+3*h^3+9*h^2*y-12*y^3)/h^3, diff(u(x, y), y)+diff(v(x, y), x) = -(6*(1+nu))*x*(h^2-4*y^2)/h^3]

sol := pdsolve(sys2)

ics := u(L, 0) = 0, v(L, 0) = 0, D[1]*u(L, 0) = 0

pdsolve([sys2, ics]);

Why Maple can't solve this PDE?

I think that the problem is on sys2. But I don't know how to explain to Maple the function: diff(u(x, y), y)+diff(v(x, y), x) = -(6*(1+nu))*x*(h^2-4*y^2)/h^3; on the system of equations. I think the problem is there.

I'm so sorry by my bad english.

I need to solve this, anyone help me please.

Thanks.

please i need assistance on how to go about contructing a 3d plot of the fuction below:

((Pi*BesselJ(1, x)*HermiteH(0, x)+2*BesselJ(0, x)-Pi*BesselJ(0, x)*BesselJ(1, x)*HermiteH(0, x))*exp(-x^2*D*t/`&alpha;k`)*BesselJ(0, x/chi)/BesselJ(1, x)^2)-M[0]*T[2]*`&gamma;gr`*exp(-T[g/T[0]]*(t-delta))

please i will appreciate a code or sort of syntax or guidline on how to do it,pls i want to plot the value of the function on the y axis, chai on the x axis and t[2] on the z axis.

M[0]=8,g=9.8,T[2]=300,500,700,900,gamma=1.17,r=1.15,T[g]=1.11111,T[0]=3.666667,t=5e-9,delta=0.002,x=3.478505,alpha=5.36,k=1.2,chi=0.22,0.23,0.24,0.25,r=1.15,D=7.46

In my calculations, I encounter with too small numbers, e.g. 0.4e-10. My question is that how can I make the maple to ignore these small numbers and considers them as zero and not to incorporate them into subsequent calculations???

Thanks in advance.

Hi, the fsolve works perfectly fine when otaining SOL2 below. However, as soon as I change the values of paramters (from 0 values in SOL2 to t_prof = .16, t_r = .16, t_w = .16 in SOL3) fsolve simplmy reproduces the eval results and would not solve! Please your help is highly appreciated. Thanks in advance!

restart;
eq1 := ((1-s)*w)^(1-gamma)*r^gamma-P_v = 0;
eq2 := (1-s)*w*H/M-(1-gamma)*P_v*q/phi = 0;
eq3 := r*(K+K_f)/M-gamma*P_v*q/phi = 0;
eq4 := prof-M*p_d*q+(1-s)*w*H+r*(K+K_f) = 0;
eq5 := -tau*y_x+q-y_d-y_g = 0;
eq6 := p_d-sigma*P_v/((sigma-1)*phi) = 0;
eq7 := y_d-M^(lambda-1)*Y*(p_d/P)^(-sigma) = 0;
eq8 := y_x-F_f*(tau*p_d)^(-sigma_x) = 0;
eq9 := y_f-M_f^(lambda-1)*Y*((1+z)*tau*p_f/P)^(-sigma) = 0;
eq10 := (G*alpha_g+Y)^(-alpha_c)/P-A*H^alpha_h/((1-t_w)*w) = 0;
eq11 := P*Y-(1-t_w)*w*H-(1-t_r)*r*K-(1-t_prof)*prof+T = 0;
eq12 := P*Y-M*p_d*y_d-M_f*(1+z)*tau*p_f*y_f = 0;
eq13 := (1-t_r)*r-r_f = 0;
eq14 := G-y_g*M^((lambda_g-1+sigma_g)/(sigma_g-1)) = 0;
eq15 := s*w*H+M*p_d*y_g-T-t_w*w*H-t_r*r*(K+K_f)-t_prof*prof-z*M_f*tau*p_f*y_f = 0;

SOL2 := fsolve(eval({eq1, eq10, eq11, eq12, eq13, eq14, eq15, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9}, [A = 7.716049383, K = 3.2, K_f = 0, alpha_c = .8, alpha_g = .2, alpha_h = 4, lambda = .5, p_f = 1, phi = .625, s = 0, sigma = 5, sigma_g = 5, sigma_x = 5, t_prof = 0, t_r = 0, t_w = 0, tau = 1.1, y_d = 1, y_f = 1, y_g = .4, y_x = 1, z = 0, lambda_g = .5, gamma = .25, gamma = .25]), {F_f, G, H, M, M_f, P, P_v, T, Y, p_d, prof, q, r, r_f, w}, {F_f = 2 .. 4, G = .1 .. .4, H = .4 .. .8, M = .4 .. .6, M_f = .3 .. .7, P = .8 .. 2, P_v = .4 .. .8, T = -.2 .. .3, Y = .7 .. 3, p_d = .9 .. 1.6, prof = .1 .. .4, q = 1.5 .. 2.7, r = 0.4e-1 .. 0.9e-1, r_f = 0.4e-1 .. 0.9e-1, w = .8 .. 3});

SOL3 := fsolve(eval({eq1, eq10, eq11, eq12, eq13, eq14, eq15, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9}, [A = 7.716049383, K = 3.2, K_f = 0, alpha_c = .8, alpha_g = .2, alpha_h = 4, lambda = .5, p_f = 1, phi = .625, s = 0, sigma = 5, sigma_g = 5, sigma_x = 5, t_prof = .16, t_r = .16, t_w = .16, tau = 1.1, y_d = 1, y_f = 1, y_g = .4, y_x = 1, z = 0, lambda_g = .5, gamma = .25, gamma = .25]), {F_f, G, H, M, M_f, P, P_v, T, Y, p_d, prof, q, r, r_f, w}, {F_f = 2 .. 4, G = .1 .. .4, H = .4 .. .8, M = .4 .. .6, M_f = .3 .. .7, P = .8 .. 2, P_v = .4 .. .8, T = -.2 .. .3, Y = .7 .. 3, p_d = .9 .. 1.6, prof = .1 .. .4, q = 1.5 .. 2.7, r = 0.4e-1 .. 0.9e-1, r_f = 0.4e-1 .. 0.9e-1, w = .8 .. 3});