# 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...

meer dan een jaar ago | 0

| accepted

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...

meer dan een jaar ago | 0

| accepted

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

meer dan een jaar 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...

meer dan een jaar ago | 0

| accepted

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...

meer dan 2 jaar 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...

ongeveer 5 jaar ago | 0

| accepted

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...

meer dan 5 jaar 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...

meer dan 5 jaar 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...

meer dan 5 jaar 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...

meer dan 5 jaar 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 ...

meer dan 5 jaar 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...

meer dan 5 jaar 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-...

meer dan 5 jaar ago | 1

| accepted

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

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

meer dan 5 jaar 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|), ...

meer dan 5 jaar ago | 1

| accepted

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;...

meer dan 5 jaar ago | 1

| accepted

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...

meer dan 5 jaar 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...

meer dan 5 jaar 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.

meer dan 5 jaar 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) =...

meer dan 5 jaar 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...

meer dan 5 jaar ago | 1

| accepted

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...

meer dan 5 jaar 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...

meer dan 5 jaar ago | 1

| accepted

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,:); ...

meer dan 5 jaar ago | 1

| accepted

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...

meer dan 5 jaar 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...

meer dan 5 jaar 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...

meer dan 5 jaar 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 ...

meer dan 5 jaar ago | 1

| accepted

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...

meer dan 5 jaar 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|.

meer dan 5 jaar ago | 1

| accepted