## 145 Reputation

7 years, 258 days

## Christoffel symbols and Ricci tensor and...

Maple 2017

I am a little bit clueless here, about how to use maple to calculate Christoffel symbol and Ricci tensor and scalar?

I read the help, but it got me confused; I have the metric ds^2 = du*dv+F(y,z)du^2+dy^2+dz^2

It's not Minkowski nor Cartesian, so how to use maple to calculate these symbols?

I am sure it's easy, but I didn't quite follow maple's instructions.

## Computing the supremum of a function wit...

Maple 2017

I want to compute the following supremum of the function.

I'll write in Latex code.

I have the following term which I want to estimate:

\delta_1(\epsilon):= \sup_{|x|<100}\sup_{ 0<= t<1/\epsilon} \epsilon \cdot |\int_0^t [ f(x,\cos s , \sin s , p_0(t)+q_0(s))-g(x,t)]ds|

where p_0(t) is an unknown function that depends on t alone.

f(x,y_1,y_2,z):=x+(y_1^2)*z

g(x,t):= \lim_{T\to \infty} 1/T \int_0^T f(x,\cos s , \sin s , p_0(t)+q_0(s))ds

q_0(s):= \exp(-s)(q_0(0)+\int_0^s (h(x_0(0),\cos(r), \sin(r))-p_0(0))dr)

where h(x,y_1,y_2):=y_1^2.

Can someone lend me a hand?

Thanks!

## Taylor series perurbation expansion...

Maple 2017

I have the following pertubation problem I want to use maple to expand for me.

We have epsilon := eps;

x(t,eps):= x_{-1}(t)/eps+x_0(t)+x_1(t)*eps

z(t,eps):=z_{-1}(t)/eps+z_0(t)+z_1(t)*eps

I want to expand a Taylor series of the following function upto some arbitray order of eps, i.e O(eps^3) or higher (depending on my mood :-)), around t=0, f(x(t,eps),z(t,eps),cos(t/eps),sin(t/eps)).

Anyone has any suggestion how to use maple 2017.3 to do this?

Thanks!

## Configurating matlab2018a with maple2017...

Maple 2017

I have installed in my UBUNTU 16.04 system matlab 2018a already, I have recently acquired maple 2017.3 (through my university).

Now while trying to install maple in my computer I am at the matlab configuration option, I picked the directory where the matlab installation is situated at, and I get the following error: The directory /home/alon/MATLAB/R2018a/bin/matlab is not writable by the current user

I searched google for this occurrence of error, and found the following suggestion: https://askubuntu.com/questions/265381/how-to-make-a-directory-permanently-writable

the first answer suggests to write in the terminal the following line: sudo chmod 775 /home/alon/MATLAB/R2018a/bin/matlab

which I did but I still get after executing this line in the terminal the above error; what else can I do to fix this problem?

Thanks.

## Monte Carlo simulation of one dimensiona...

Maple 2015

I want to use maple2015 to perform a Monte-Carlo simulation of a one dimensional Harmonic Oscillator.

Consider a particle having displacements, x=na where n is an integer, i.e 0 plus minus one, etc.

The potential energy of the particle is given by U(x)= 1/2 kx^2 = 1/2 ka^2 n^2.

For this simulation will choose ka^2 = 0.01 k_B T where k_B is Boltzmann's constant, and T is the temprature in Kelvin.

So we should perform a Monte-Carlo simulation starting from x(0)=20a, and perfroming individual steps by selecting an attmept to move x=+-a ,with equal probability, and choose whether to make the actual step according to energy change expected in that step.

I need to draw particle's position and x(t), and particle's energy E(t).

After that I need to calculate and draw the autocorrelation functions \phi_x(t) and \phi_E(t).

I found some code that might help me, but I am nor sure how to implement the above two lines on maple; your help is appreciated.

http://pubs.acs.org/doi/suppl/10.1021/ed100414p/suppl_file/ed100414p_si_001.pdf

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