# Andrew Newell

A geophysicist who uses MATLAB for most of his modeling.

Professional Interests: geophysics

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**Content Feed**

How do I generate a random number with beta distribution?

You can use the function betarnd, but you'll need to do some normalizing to get it in the standard form used by MATLAB (see Beta...

6 months ago | 0

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Newton Raphson - saving all values and using last iteration value as initial for next

Sorry, I just realized that you wanted to save the iterations. Here's how: x = -0.001*ones(6,length(A1)); for i=1:5 x(i+1...

6 months ago | 0

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Newton Raphson - saving all values and using last iteration value as initial for next

O.k. So here is how you do it: x = -0.001*ones(size(A1)); for i=1:5 x = x - f(x)./fd(x); end

6 months ago | 0

Finding tangent plane with the max range value and z value being equal

Notice that is empty, then try this: X = -1.41:0.01:1.41; [~,idx] = min(abs(X-1)); disp(X(idx)-1) This being floating point...

6 months ago | 0

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MatCont for Homotopy Method

The primary purpose of MatCont (which is a GUI front end for Cl_MatCont) is to analyze solution curves of the form . These may b...

1 year ago | 0

Coupled Differential Equations - derivatives on both sides of equations

Let's simplify things a little bit so we can better see what is going on. Let Y = [x; y]; G1(t,Y) = 0.000053+g1(Y(1),t...

4 years ago | 0

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Why doessn't my code work for compsite simpson one third rule?

You weren't defining the function properly. Try this: func=@(x) 1+exp(-x); See <https://www.mathworks.com/help/matlab/ma...

4 years ago | 0

how to continue code in next line with comment between them

You can have the comments beside each part instead: a=b+c+f... % line 1 +t+h+k; % line 2 However, it is possib...

4 years ago | 0

Class Property: Array of Objects

You need to define a get method (see <https://www.mathworks.com/help/matlab/matlab_oop/access-methods-for-dependent-properties.h...

4 years ago | 0

Series Summation With Function Handles

In principle, you can use |matlabFunction| to get around this difficulty. However, I noticed a couple of issues. First, the summ...

4 years ago | 1

How to overlay a curve over histogram?

If you already have the curve, then just type |hold on| and plot it. An example: ydata = randn(1000,1); hist(ydata) hold ...

4 years ago | 0

How to create a new variable for each iteration of a while loop?

Structures are great for this kind of task (see <https://www.mathworks.com/help/matlab/ref/struct.html struct>). Here is an exam...

4 years ago | 1

How to store multiple serial objects

You certainly can store them in an array, e.g.: n = 8; s = cell(8,1); for ii=1:8 s{ii} = serial(sprintf('COM1%d',ii-...

4 years ago | 1

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How can I fix my error with the passing a function to another fuction?

The first line should be f = @(x) exp(x);

4 years ago | 0

Integration of norminv function

The problem is that |norminv(x,0,1)| goes to |-Inf| as |x| goes to zero and |Inf| as |x| goes to 1 (and ditto for |y| and |z|), ...

4 years ago | 1

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How to plot a matrix in polar coordinates with color?

I think most approaches will involve converting the coordinates to Cartesian. Here is one approach: v0=10; A=4.*v0./pi;k=1;...

4 years ago | 1

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Nonlinear Tangent (trigonemetric) equation

Before trying to find zeros for a function, it's a good idea to plot it so you understand the nature of the problem. If you do t...

4 years ago | 0

How to calculate the integral of a function with a spline in it

For evenly or unevenly spaced data, you could use the trapezoidal rule (MATLAB function <https://www.mathworks.com/help/matlab/r...

4 years ago | 0

Offseting the y axis to make data more clear

After yyaxis right; use a command like ylim([-0.1 1.5]) to move the axes.

4 years ago | 0

Logical Test on Matrix Failing

The variable |little_endian_message| is a char representation of binary numbers. Try this: if( little_endian_message(a) =...

4 years ago | 0

Plots with stairs and inclines?

I'm not sure how you intend to generate the points, but for the example plot you gave, |plot| works just fine with an appropriat...

4 years ago | 1

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Quiver Plot Arrows too Wide

Have you tried looking at <https://www.mathworks.com/help/matlab/ref/quiver.html the documentation for quiver>? There is an opti...

4 years ago | 0

Collection many vectors in one matrix

The answer is G = [I1; I2; I3]; See <https://www.mathworks.com/help/matlab/math/creating-and-co%E2%80%A6 Creating and Co...

4 years ago | 1

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How can I speed my function?

One source of delays can be |repmat|. This can be replaced by a suitable choice of index, as in the following: r = R(i,:); ...

4 years ago | 1

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Overwriting While-loop conditional with +Inf

MATLAB evaluates a logical expression like your |while| condition from left to right. If |a==1|, it knows the expression is fals...

4 years ago | 0

How to Simplify an symbolic expression

If I define a= 2*atan((-2+sqrt(4-gama^2 *l^2* M^2-4* gama *l* M^2 *tan(gama/2)+4* tan(gama/2)^2-4 *M^2 *tan(gama/2)^2))/(ga...

4 years ago | 0

How to load *.mat file from each directories in new script?

Here is a solution that assumes there is one of these |.mat| files in every subdirectory of each of the 15 directories. Let's al...

4 years ago | 0

Old form of legend('string 1','string 2',2) ??

Actually, it's NW (see the <http://www.mathworks.com/help/releases/R13sp2/techdoc/ref/legend.html?s_tid=srchtitle documentation ...

4 years ago | 1

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Finding normals to contours on contour plot

You want curves to follow the gradients. It's easy enough to <https://www.mathworks.com/help/matlab/creating_plots/display-quive...

4 years ago | 0

How do I set the limits on the secondary y axis?

Use <https://www.mathworks.com/help/matlab/ref/ylim.html ylim> right after |yyaxis right|.

4 years ago | 1

| accepted