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ODEs strange behaviour
Hello, people, I am desperate. I have a system of ODE.
In simple case it is just an oscillator, in harder case it is oscillator with attenuation.
The hardest case is the force that must bring opposite effect to attenuation.
So, my system is in file parallelDegreesW4
function xDot = parallelDegreesW4(t,x,~,w_af,g_af,gcurr)

xDot = [x(2); ... %//= theta'
    
    sin(x(1)) * cos(x(1)) * ((x(4))^2) + ...
    (w_af^2) * ((sin(x(1)))^3 * cos(x(1)) * (cos(x(3)))^4 + (sin(x(1)))^3 * cos(x(1)) * (sin(x(3)))^4 - (cos(x(1)))^3 * sin(x(1)) ) + ...
    2 * g_af * x(2) + ...
    - 2 * gcurr * sin(x(1)) * cos(x(1)) * sin(x(3)) * cos(x(3)); ...
    
    x(4); ... %//= phi'
    
    - x(2) * x(4) * cot(x(1)) + ...
    (w_af^2) * (sin(x(1)))^2 * cos(x(3)) * sin(x(3)) *(-(cos(x(3)))^2 + (sin(x(3)))^2) + ...
    2 * g_af * x(4) + ...
    - gcurr * ((cos(x(3)))^2 - (sin(x(3)))^2)];
 
end
   
So, w_af - frequency, g_af - attenuation parametr, gcurr - reverse to attenuation.
MY question is:
While I call my callDegrees(0.1,0.01,0) function nothing happens that is needed.
function f = callDegrees(w_af, g_af, gcurr)
    x0=[pi/2; 0; 0.01; 0];
    tspan = 0:0.1:500;
     options = odeset('RelTol',1e-2,'AbsTol',[1e-3 1e-3 1e-3 1e-3]);

    [t,x] = ode45('parallelDegreesW4',tspan,x0, options, w_af, g_af, gcurr );
Any remarks would be helpful.
Can I optimise somehow my system?
Why my computer is doing this so slowly?
Whe ode15s gives terrible results when ode45 gives fine with the same Tolerances
Mammogram image enhancement

Enhancement of mammogran images for clear view of pictorial muscles and cancer affected region

Re: Comparing Financial time series from two sources in MATLAB
Any updates on this query, please? Thanks.

On Wednesday, March 25, 2015 at 8:00:53 AM UTC+5:30, Amar M wrote:
> Any comments on this question? I would assume this would be an easy one for Statistics enthusiasts using MATLAB.
>
>
> On Monday, March 23, 2015 at 1:17:27 PM UTC+5:30, Amar M wrote:
> > Any comments on the problem?
> > Appreciate your help.
> >
> >
> > On Saturday, March 21, 2015 at 8:58:43 AM UTC+5:30, Amar M wrote:
> > > Hello,
> > >
> > > I need help performing analysis in MATLAB which compares financial time series (like PRICE_CLOSE, PRICE_RETURN and SECURITY_MARKET_CAP) originating from 2 different sources (vendors) (say A [testing source] and B [benchmark source - more reliable source]).
> > >
> > > Other aspects of analysis which needs to be considered:
> > >
> > > 1. Time series ranges for more than 20 years of data (business days) for more than 10,000 securities having daily data coming from both sources for all 3 data points mentioned above.
> > > 2. Comparison analysis needs to be done for each of the 3 data points individually
> > > 3. Basic idea is to understand at what time point, testing source data point value is how much different from corresponding benchmark source data point.
> > > 4. There would be instances where testing source provides data but corresponding benchmark source reports NaN value, and vice-versa.
> > >
> > > I need suggestions with respect to comparing both data sources in terms of statistics and which MATLAB tools/functions I could use for achieving the same.
> > >
> > > Relevant Tests I could think of (please correct if not applicable) -
> > > Correlation analysis across time across securities, Graph plots on coverage across time for each data point in terms of security count, etc.
> > >
> > > Please advise. I'd appreciate quick response, if possible.
> > >
> > > Also, do let me know if I may provide more information.
DavidMercier/PopIn

"Pop-in" Analysis From Indentation Tests

Re: Plot a 3D object
Sergey Gordienko" <gordienko@radis.ru> wrote in message <meh80e$nb$1@newscl01ah.mathworks.com>...
>It seems there is no general approach for such tasks. Here is one example (thanks to tech support):
x=-5:0.05:5;
y=-5:0.05:5;
[xx,yy]=meshgrid(x,y);
[xxx,yyy]=meshgrid(x,y);

zz=-2*xx.*xx-2*yy.*yy;
surf(xx,yy,zz);
hold on

zzz=-50+2*(xxx).^2+2*(yyy).^2;
surf(xxx,yyy,zzz);

ind = (zzz - zz)<0;

z = NaN (size(zz));
z(ind) = zz(ind);
figure
surf(xx,yy,z);
hold on
z = NaN (size(zzz));
z(ind) = zzz(ind);
mesh(xxx,yyy,z);

We plot a 3d object constituted by two paraboloids
Re: Isosurface data
Luigi" <files@mathworks.com> wrote in message <mf3cvo$28g$1@newscl01ah.mathworks.com>...
> Hi to everybody.
>
> I have an isosurface, generated with isosurface function, so I have a struct in my workspace as follow
>
> surface
>
> tri: [93372x3 int32]
> vert: [47915x3 single]
>
> when I plot it I have the results showed in attacched image.
>
> Now, I want to select a subset of points of isosurface and generate a new isosurface starting from this selected points.
>
> For example, I want to extract from the isosurface only the points included inside the red circle, selecting with datacursor the center of each black dot and creating a new isosurface starting from the coordinates of each black dot.
>
> I hope it's clear and that you can help me.
>
> Thanks in advance
>
> Best regards
>
> Luigi

You should find the image here

http://www.filedropper.com/image_5

thank you so much
Isosurface data
Hi to everybody.

I have an isosurface, generated with isosurface function, so I have a struct in my workspace as follow

surface

 tri: [93372x3 int32]
vert: [47915x3 single]

when I plot it I have the results showed in attacched image.

Now, I want to select a subset of points of isosurface and generate a new isosurface starting from this selected points.

For example, I want to extract from the isosurface only the points included inside the red circle, selecting with datacursor the center of each black dot and creating a new isosurface starting from the coordinates of each black dot.

I hope it's clear and that you can help me.

Thanks in advance

Best regards

Luigi
Polynomial Transformation of Image and Points
Hi,

I warp images with the imwarp function using a tform (PolynomialTransformation2D) object. For every image I have landmarks which have to be transformed accordingly to the image transformation.

I wanted to use transformPointsForward and put the same tform in it like in imwarp, but transformPointsForward can't handle PolynomialTransformation2D transformations. Since transformPointsInverse can handle PolynomialTransformation2D, this doens't make sense to me.

So is their a possibility to transform points according to a imwarp image warping?

Regards,
Franziskus
How to capture output of disp
I would like to capture the output of disp in order to capture a short descriptive text string of an cell array with arbitrary contents.


>> q={'test' zeros(1000,1) @(a,b)a+b 6};
>> disp(q)
    'test' [1000x1 double] @(a,b)a+b [6]

I would essentially like to be able to do something like:

s=disp(q);

but that does not work. Does anybody know some kind of trick that allows me to capture the output of function calls like this?
Uniform Colorbar for non-linear contour levels

The contour function in MATLAB plots contour data on a linear color scale. This means that non-linear contour levels appear unevenly spaced on the colorbar. Contour levels spaced very close to each other relative to the range of the data can be difficult to distinguish on the colorbar.
generalCbar.m can help!
Plug in the 2-d data, the x
and y grids and the contour levels at any desired values. Optionally, you can also enter the rgb colormap of your choice and the number of colors you want to see on the colorbar. The output will be a contour plot with contour levels placed at uniform intervals on the colorbar regardless of the spacing between the contour levels. The function also returns the handles to the axes, the contour plot and the colorbar.

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