abdulganiy

145 Reputation

6 Badges

9 years, 340 days

MaplePrimes Activity


These are questions asked by abdulganiy

In the following code, I want the base of the logarithm in the label to appear at the conventional position not beside the logarithm. How can I achieve this? Thank you all in anticipation of your educative response and do stay safe.

restart;

B:=<<39,76,151,301,601>|<7.71E-8,5.43E-9,3.55E-10,2.11E-11,1.32E-12>|
	<26,51,101,201,401>|<6.46E-3,1.17E-4,1.88E-6,2.96E-8,4.46E-10>|
	<26,51,101,201,401>|<2.74E-4,6.34E-6,1.16E-7,1.85E-9,2.92E-11>|
	<26,51,101,201,401>|<6.48E-4,4.39E-5,2.99E-6,1.88E-7,1.18E-8>>:

for i from 1 to 5 do
   B[i, 2] := log[10](B[i, 2]):		  			
   B[i, 4] := log[10](B[i, 4]): 		
   B[i, 6] := log[10](B[i, 6]): 		
   B[i, 8] := log[10](B[i, 8]):	
       

   
end do:  # computing the log of the max-error
B: # This is the table of values we'll plot.

T:=plot([B[..,[1, 2]],B[1..1,[1, 2]], B[.., [3, 4]],B[1..1,[3, 4]], 
	 B[..,[5, 6]],B[1..1,[5, 6]],B[.., [7, 8]],B[1..1,[7, 8]]], 
	legend = ["","BFFM","", "BHT","", "BHTRKNM", "", "BNM"],
	#title="Efficiency Curve for Example 1",
	style = ["pointline","point","pointline","point","pointline","point","pointline","point"], 
	symbolsize = 15,axes = framed, 
	symbol = [box,box, circle,circle,diamond,diamond,solidcircle, solidcircle],
	color=[red, red, blue,blue, black, black, green, green], 
	axis = [gridlines = [colour = green, majorlines = 1,linestyle = dot]], 
	labels = ["NFE", "log[10](Max Err)"]);

 

I have written the following attached code to use Euler explicit method to solve the following IVP

diff(y(x), x) = 2*(1+x)-y(x), y(2) = 5
With Exact solution  y(x) = 2*x+exp(-x)/exp(-2)

However, I found out that my exact results are not correct while the numerical results are okay. What have I done wrong in the code? Can someone modify the code?

Thank you and kind regards.

Dear all,

Please I want only 8 points to show on this curve, how do I specify it?

plot(ln(1+sin(Pi*x)), x = 0 .. 1, legend = numerical, style = point, symbol = box, color = blue, symbolsize = 15, numpoints = 8);

Thank you all and kind regards.

Please do keep safe amidst this global pandemic.

Dear All.

I hope we are all staying safe.

Please I want to solve Sine Gordon Equation using a numerical method I constructed (non-classical), I need to compare the result of the method with the exact solution to generate the errors. However, since the exact solution has two variables, x, and t, I really don't know how to accommodate the two in my coding.

Can someone be of help in this regard?

Thank you and kind regards

 


Download Discretization_of_Sine_Gordon_Equation.mw

Download Sine_Gordon_Implementation_Trial.mw

 

Dear All.

Please kindly help to correct the attached code on discretization of fourth order PDE using method of line.
Thank you and kind regards.

restart

``

``

Discretization of parabolic equation with method of line

diff(u(x, t), t) = -2*(diff(diff(u(x, t), x), x))-(diff(diff(diff(diff(u(x, t), x), x), x), x))-u(x, t)*(diff(u(x, t), x))

u(x, t)

u(x, t)

u(x, 0) = 0.3e-1*sin(x)

8

``

``

``

Convert the BC to finite difference

(1/2)*(u[m+1](t)-u[m-1](t))/h

(u[m-1](t)-2*u[m](t)+u[m+1](t))/h^2

(u[m-2](t)-4*u[m-1](t)+6*u[m](t)-4*u[m+1](t)+u[m+2](t))/h^4

````

Convert the governing equation to finite difference form

Error, invalid input: diff received 2*h, which is not valid for its 2nd argument

Error, invalid input: diff received 2*h, which is not valid for its 2nd argument

Error, invalid input: LinearAlgebra:-GenerateMatrix expects its 1st argument, eqns, to be of type ({list, set})({`=`, algebraic}), but received eqs

A

``


 

Download Discretization_of_PDE_Order_4.mw

2 3 4 5 6 7 8 Page 4 of 8