I have a 3D matrix with 8x8x8 (x,y,z).so i got 56 points n 16 points for boundary.At first i use a formula of finite difference approximation to the 4th order operator given by
[ 1 ;
1 -4 1 ;
1 -8 20 -8 1 ;
1 -4 1 ;
1 ].
And the boundary when u=0, 0.5cos(v). u=1,0.2cos(v) which v=0:2*pi/8:2*pi. And tangency condition is x(-1,j)=x(1,j)-2hg(j).
h=1/8; X(0,v)=(-0.5cos v,-0.5sin v,-0.5);X(1,v)=(-1cos v,-1sin v,0)

After i form al the matrix,still cannot get the 3D smooth vase shape which is with many colors.i dont know what wrong with my programming in Matlab.

If there is a possibility how its done, that would help me a lot.Thanks for the idea and comments..I have a 3D matrix with 8x8x8 (x,y,z).so i got 56 points n 16 points for boundary.At first i use a formula of finite difference approximation to the 4th order operator given by
[ 1 ;
1 -4 1 ;
1 -8 20 -8 1 ;
1 -4 1 ;
1 ].
And the boundary when u=0, 0.5cos(v). u=1,0.2cos(v) which v=0:2*pi/8:2*pi. And tangency condition is x(-1,j)=x(1,j)-2hg(j).
h=1/8; X(0,v)=(-0.5cos v,-0.5sin v,-0.5);X(1,v)=(-1cos v,-1sin v,0)

After i form al the matrix,still cannot get the 3D smooth vase shape which is with many colors.i dont know what wrong with my programming in Matlab.

If there is a possibility how its done, that would help me a lot.Thanks for the idea and comments.. I have a 3D matrix with 8x8x8 (x,y,z).so i got 56 points n 16 points for boundary.At first i use a formula of finite difference approximation to the 4th order operator given by
[ 1 ;
1 -4 1 ;
1 -8 20 -8 1 ;
1 -4 1 ;
1 ].
And the boundary when u=0, 0.5cos(v). u=1,0.2cos(v) which v=0:2*pi/8:2*pi. And tangency condition is x(-1,j)=x(1,j)-2hg(j).
h=1/8; X(0,v)=(-0.5cos v,-0.5sin v,-0.5);X(1,v)=(-1cos v,-1sin v,0)

After i form al the matrix,still cannot get the 3D smooth vase shape which is with many colors.i dont know what wrong with my programming in Matlab.

If there is a possibility how its done, that would help me a lot.Thanks for the idea and comments.. 4th order partial differentiation equation, 3d matrix, 3d plots MATLAB Answers — New Questions

​

I have a system of equations:

This system satisfies a relation
where is an initial condition.
For I plotted the relation y in two ways:
First way by solving the system numerically using ode45 with RelTol 1e-12 and AbsTol 1e-15 and by having the solution for x I plotted y.
Second way by solving the equation again with ode45 with Reltol 1e-9 and Abstol 1e-12 and then defining y=… and plotting it.
However, the plots are very different and I don’t understand the reason why:
Here is the plot by first method:

Here is the plot by second method:

Help is appreciated!I have a system of equations:

This system satisfies a relation
where is an initial condition.
For I plotted the relation y in two ways:
First way by solving the system numerically using ode45 with RelTol 1e-12 and AbsTol 1e-15 and by having the solution for x I plotted y.
Second way by solving the equation again with ode45 with Reltol 1e-9 and Abstol 1e-12 and then defining y=… and plotting it.
However, the plots are very different and I don’t understand the reason why:
Here is the plot by first method:

Here is the plot by second method:

Help is appreciated! I have a system of equations:

This system satisfies a relation
where is an initial condition.
For I plotted the relation y in two ways:
First way by solving the system numerically using ode45 with RelTol 1e-12 and AbsTol 1e-15 and by having the solution for x I plotted y.
Second way by solving the equation again with ode45 with Reltol 1e-9 and Abstol 1e-12 and then defining y=… and plotting it.
However, the plots are very different and I don’t understand the reason why:
Here is the plot by first method:

Here is the plot by second method:

Help is appreciated! plot, figure, ode45, differential equations, matlab MATLAB Answers — New Questions

​

Hi, so I desired to create HRSG model for simulation purposes (one of the objectives for Final Year Project (FYP), unfortunately since I have a novice background in the mechanical field ( I’m in electrical engineering field), I have no idea where /how to start. Could anyone give me some pointers what info should I look for/ or suggest any open sources / materials of HRSG simulink models to kickstart my project?Hi, so I desired to create HRSG model for simulation purposes (one of the objectives for Final Year Project (FYP), unfortunately since I have a novice background in the mechanical field ( I’m in electrical engineering field), I have no idea where /how to start. Could anyone give me some pointers what info should I look for/ or suggest any open sources / materials of HRSG simulink models to kickstart my project? Hi, so I desired to create HRSG model for simulation purposes (one of the objectives for Final Year Project (FYP), unfortunately since I have a novice background in the mechanical field ( I’m in electrical engineering field), I have no idea where /how to start. Could anyone give me some pointers what info should I look for/ or suggest any open sources / materials of HRSG simulink models to kickstart my project? hrsg, whrb, ccgt, energy recovery heat exchanger, heat exchanger, simulink, mechanical MATLAB Answers — New Questions

​

Hello everyone,
I am working on Electric vehicle charging station location and plannimng problem. The idea is, that given any city map, we should be able to plan and size the Electric vehicle charging stations locations on a map. For the same, I want to be able to input the city map via google, OpenStreet etc, and my code should be able to read the road network details, like nodes, distance, width, unidirectional or bidirectional road etc.
To be honest, I have made zero progress in that. Using geoplot function, I can read the location, and I can also see the road layout, but Im not able to get anything more out of it.
I already read the document on roadprops,but it isnt useful. I figured its something to do with image processing.
Any help or an example or links would be appreciatedHello everyone,
I am working on Electric vehicle charging station location and plannimng problem. The idea is, that given any city map, we should be able to plan and size the Electric vehicle charging stations locations on a map. For the same, I want to be able to input the city map via google, OpenStreet etc, and my code should be able to read the road network details, like nodes, distance, width, unidirectional or bidirectional road etc.
To be honest, I have made zero progress in that. Using geoplot function, I can read the location, and I can also see the road layout, but Im not able to get anything more out of it.
I already read the document on roadprops,but it isnt useful. I figured its something to do with image processing.
Any help or an example or links would be appreciated Hello everyone,
I am working on Electric vehicle charging station location and plannimng problem. The idea is, that given any city map, we should be able to plan and size the Electric vehicle charging stations locations on a map. For the same, I want to be able to input the city map via google, OpenStreet etc, and my code should be able to read the road network details, like nodes, distance, width, unidirectional or bidirectional road etc.
To be honest, I have made zero progress in that. Using geoplot function, I can read the location, and I can also see the road layout, but Im not able to get anything more out of it.
I already read the document on roadprops,but it isnt useful. I figured its something to do with image processing.
Any help or an example or links would be appreciated image processing, maps, road MATLAB Answers — New Questions

​

I test the efficiency of using a good StartVector in eigs.
The code is quite simple.
First, I use eigs to figure out the eigenvector v1,
then I use this eigenvector v1 as the StartVector to run eigs again.
I expect that much less time might be needed now.

Nevertheless,
the time cost shows no improvement at all.

My code is as follows
———————————————————————-

format long

n = 3000;
A = rand(n,n);
A = A + A’;

tic
[v1,eta1]=eigs(@(vec)test_eigs(vec,A),n,1,’lm’,’Display’,0,’IsFunctionSymmetric’,0,’MaxIterations’,300);
toc

StartVector = v1;
tic
[v2,eta2]=eigs(@(vec)test_eigs(vec,A),n,1,’lm’,’Display’,0,’IsFunctionSymmetric’,0,’MaxIterations’,300,’StartVector’,StartVector);
toc

eta1
eta2

function vec1 = test_eigs(vec0,A)
vec1 = A * vec0;
end
————————————————————————————

The output is as follows
~~~~~~~~~~~~~~~~~~~~~~

Elapsed time is 0.069811 seconds.
Elapsed time is 0.066047 seconds.

eta1 =

3.000980119229400e+03

eta2 =

3.000980119229400e+03
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So my question is,
is there anything wrong in my understanding about StartVector in eigs?

Any suggestion or comment would be greatly appreciated.I test the efficiency of using a good StartVector in eigs.
The code is quite simple.
First, I use eigs to figure out the eigenvector v1,
then I use this eigenvector v1 as the StartVector to run eigs again.
I expect that much less time might be needed now.

Nevertheless,
the time cost shows no improvement at all.

My code is as follows
———————————————————————-

format long

n = 3000;
A = rand(n,n);
A = A + A’;

tic
[v1,eta1]=eigs(@(vec)test_eigs(vec,A),n,1,’lm’,’Display’,0,’IsFunctionSymmetric’,0,’MaxIterations’,300);
toc

StartVector = v1;
tic
[v2,eta2]=eigs(@(vec)test_eigs(vec,A),n,1,’lm’,’Display’,0,’IsFunctionSymmetric’,0,’MaxIterations’,300,’StartVector’,StartVector);
toc

eta1
eta2

function vec1 = test_eigs(vec0,A)
vec1 = A * vec0;
end
————————————————————————————

The output is as follows
~~~~~~~~~~~~~~~~~~~~~~

Elapsed time is 0.069811 seconds.
Elapsed time is 0.066047 seconds.

eta1 =

3.000980119229400e+03

eta2 =

3.000980119229400e+03
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So my question is,
is there anything wrong in my understanding about StartVector in eigs?

Any suggestion or comment would be greatly appreciated. I test the efficiency of using a good StartVector in eigs.
The code is quite simple.
First, I use eigs to figure out the eigenvector v1,
then I use this eigenvector v1 as the StartVector to run eigs again.
I expect that much less time might be needed now.

Nevertheless,
the time cost shows no improvement at all.

My code is as follows
———————————————————————-

format long

n = 3000;
A = rand(n,n);
A = A + A’;

tic
[v1,eta1]=eigs(@(vec)test_eigs(vec,A),n,1,’lm’,’Display’,0,’IsFunctionSymmetric’,0,’MaxIterations’,300);
toc

StartVector = v1;
tic
[v2,eta2]=eigs(@(vec)test_eigs(vec,A),n,1,’lm’,’Display’,0,’IsFunctionSymmetric’,0,’MaxIterations’,300,’StartVector’,StartVector);
toc

eta1
eta2

function vec1 = test_eigs(vec0,A)
vec1 = A * vec0;
end
————————————————————————————

The output is as follows
~~~~~~~~~~~~~~~~~~~~~~

Elapsed time is 0.069811 seconds.
Elapsed time is 0.066047 seconds.

eta1 =

3.000980119229400e+03

eta2 =

3.000980119229400e+03
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So my question is,
is there anything wrong in my understanding about StartVector in eigs?

Any suggestion or comment would be greatly appreciated. eigs MATLAB Answers — New Questions

​