# Matt J

Professional Interests: medical image processing, optimization algorithms

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**Content Feed**

Expressing polynomial including a indefinite parameter

One way. p = @(x,a) polyval([a,-4,2-a],x); Usage: x=1; a=2; p(x,a)

circa 2 ore ago | 1

Combining 3 2D graphs into a 3D figure

Something like the following, perhaps? x=linspace(0,5); z1=x.*exp(-x); z2=3*x.*exp(-4*x); Hax=axes; area(x,z1,'Parent',up...

circa 2 ore ago | 0

How can I minimize absolue value in a power optimprob?

The objective is to minimize the integral of Pgrid abs value... while the control variables are Pbatt and Pev; Ppv and Pload If...

circa 5 ore ago | 0

| accepted

Finding out what initial guesses the curve fitting toolbox made for curve fit

I don't think there's anyway to dig out the initial guess generated inside fit(), but why not just specify your own random start...

circa 20 ore ago | 0

| accepted

I have two arrays that I want to divide a specific way

C=A./B;

circa 21 ore ago | 0

| accepted

When I export the figure, the x-axis is halved even though I have set the interval in the code.

I usually use export_fig(), https://github.com/altmany/export_fig

circa 23 ore ago | 0

How to fill a hollow donut-shaped object so that it looks like a circle?

load Image montage( {BW, imfill(BW,'holes')}, [],'Back','w','Bor',5)

circa 23 ore ago | 0

| accepted

Is there a way to set MaxSQPIter for active-set algorithm under fmincon?

Probably because you didn't pass options to fmincon. Otherwise, show us your code.

1 giorno ago | 0

histc problem in counting in particular bin

You are assuming that the bin boundaries are calculated with infinite precision, which is impossible. Likewise your data is also...

1 giorno ago | 0

| accepted

Replace value that are associated to a location by nan

spl(0<= elevation & elevation<=100)=nan;

1 giorno ago | 0

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Fit dataset to another dataset

See polyfit(). https://www.mathworks.com/help/matlab/ref/polyfit.html

1 giorno ago | 0

optimization of matrices with random initialization

Make sure your objective function code does not contain any randomization steps. Your initial guess can be random, but the objec...

1 giorno ago | 0

| accepted

HOW TO REVERSE THE BINARY IMAGES

outt33(:,:,i) = ~imbinarize( I)

1 giorno ago | 0

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What dose this function mean and what is the differentes ?

The first is calculating the number of zeros in B and the second is summing all values in B (times -1).

1 giorno ago | 0

Error in lsqcurvefit with 3 unknown parameters involved

If your model has 3 unknown parameters, then your initial guess P40 must be a vector of length 3.

1 giorno ago | 0

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sum only consecutive 1's in matrix

See, Tools for Processing Consecutive Repetitions in Vectors https://www.mathworks.com/matlabcentral/fileexchange/78008-tools...

1 giorno ago | 0

what is the fastest appproach to solve a system of non linear equations ?

Seems like it would make sense to regard this as a system of 100K simultaneous equations and solve for the PDE parameter with ls...

2 giorni ago | 0

How do we allocate equidistant points on a sinusoidal curve?

You should also have a look at interparc() https://www.mathworks.com/matlabcentral/fileexchange/34874-interparc?s_tid=srchtitle...

2 giorni ago | 0

How do we allocate equidistant points on a sinusoidal curve?

You can use fzero, x_p=0; y=@(x) -25*sin((2*pi/50)*x); fun=@(d) d.^4+( y(x_p+d^2)-y(x_p)).^2 - 0.004^2; x=x_p+fzero(fu...

2 giorni ago | 1

| accepted

drawrectangle draws rectangle even though the mouse is clicked outside the parent UIAxes

You can fall back to imrect, if necessary fcn = makeConstrainToRectFcn('imrect',get(gca,'XLim'),get(gca,'YLim')); h=imrect('Po...

2 giorni ago | 0

create nononteger random matrix in certain range

200*rand(5)-100

2 giorni ago | 1

| accepted

Array processing using Taylor Series and FOR Loops to approximate sin value for each element in that array.

The array can be of any type and dimensions. If so, why does your code assume it will be 2D? Can't it be 3D or 4D? In any case...

3 giorni ago | 0

| accepted

How to store iterative information to a matrix?

The following is pretty typical. result=nan(big_number,1); while abs(y)>=small_number &iteration<big_number [x,y] = some...

3 giorni ago | 0

how to generate points inside a rectangle not parallel to axis in Matlab

You mean you want to generate N random points? If so, then, xy=Q*([length;width].*(rand(2,N)-0.5)) + center(:)

3 giorni ago | 0

| accepted

How do I add zero padding to this convolution?

Not sure what the question is, but you can easily compare your result to direct convolution to see if it's correct. x1x2_conv =...

4 giorni ago | 1

How to tell an multi-output anonymous function to vectorize its output components which are constant

One way, f=@(x,y) completeRows({x+y;2;x*y;x.^2-1;3}); f([1 2],3) function out=completeRows(C) n=max(cellfun('length',...

5 giorni ago | 0

| accepted

Area between three curves

A=Einspeiseanteil; B=GabelstaplerP; C=max(A,B); area=trapz(X,(C-Y).*(C>=Y))

5 giorni ago | 0

How to plot vectors exactly on the edge of another graph?

t=linspace(0,360,91); t(end)=0; u=cosd(t); v=sind(t); fimplicit(@(a,b) a.^2+b.^2-1);hold on quiver(u,v,u,v,'Color','r...

6 giorni ago | 1

| accepted

How can I assign values to min/max of a column within each value of another column?

Let's call your table T, then, T=table(randi(2,10,1), randi(100,10,1), rand(10,1),'V',{'Device','Time','current'}) str=[""...

6 giorni ago | 0

| accepted