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# Joseph Cheng

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609 total contributions since 2014

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Radiation Heat Transfer — View Factors (1)
View factors (aka configuration factors) are utilized in some radiation heat transfer models to estimate heat transfer rates bet...

3 maanden ago

i got index exceeds matrix dimensions.??
You should put a breakpoint at that line and then check the dimensions of the curs variable. without running your code and with...

ongeveer een jaar ago | 0

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Replotting Data vs. Storing Plots/Images
I think the answer would be dependent on how many points are in each line and the size of the images you're going to be pulling ...

meer dan 2 jaar ago | 0

How to create a checkerboard matrix without inbuilt function.
There are much easier ways to do this than nested for loops, reshape is readily available. if you *must* do it with for loops y...

meer dan 2 jaar ago | 0

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does someone know if it's possible to have popupmenu in inputdlg?
Absolutely you can, however its not as straight forward as inputdlg() or questdlg(). you'll want to look at the example here: ...

meer dan 2 jaar ago | 0

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How can I change the LSBs of consecutive elements of an array?
you could use bitand() a = [23, 255, 67, 89, 45, 90, 34, 12]'; n=3; b = bitand(a ,255-n,'uint8') disp(dec2bin(a)) di...

meer dan 2 jaar ago | 0

import multiple spreadsheats at once (.xlsx files)
well first you'll want to get away from generating variables in that fashion as you'll basically have A400 or more which is hard...

meer dan 2 jaar ago | 0

Looking for a word in a 2D array
I would take a look at the function strfind(), and lower() or upper(). strfind() will return the starting index value of the ...

meer dan 2 jaar ago | 0

Project 3D points to a surface
you could try something like this. my curve and fit method is probably different however what you can do is use find() to deter...

meer dan 2 jaar ago | 1

Can I match data from several find functions?
what you should do is get rid of the find() for each parameter filter. keep it as a logical and then you can directly use the l...

meer dan 2 jaar ago | 0

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How to average plots that differ in x and y data?
you can do something like x1 = 0:.01:4; x2 = 0:.03:5; x3 = 0:.02:6; y1 = sin(3*pi*x1); y2 = sin(3*pi*x...

meer dan 2 jaar ago | 0

How to get the central data of a matrix?
you'd use the parameter 'same' in the convolution function x = [0 1 2 3 4 5 4 3 2 1 0] conv(x,[0 1 0],'same') otherwise ...

meer dan 2 jaar ago | 0

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Change axes limits interactively
you can try something like this, which really depends on how you want the user to input the different limits function uiexa...

meer dan 2 jaar ago | 1

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error using randi: size inputs must be scalar
you actually want to do for n=1:4 a{n}= randi(10,n)-1; b{n}= randi(10,n)-1; fprintf('n = %d:\n', n)...

meer dan 2 jaar ago | 0

How can I plot mean +/- 1 standard deviation for every data point in my dataset ?
have you looked up the function errorbar()? it should get you what you'll need

meer dan 2 jaar ago | 0

searching through RNA sequence for a string of characters
so, do you store the full compliment data in an array such that you can %gen dummy data comp = 'AGCT'; list = comp(ran...

meer dan 2 jaar ago | 0

Outputting gyroscope data to array
you're overwriting it with the p(n) as n only goes from 1 to 10 again and again. you'll have to increment p(#) beyond n or mult...

bijna 3 jaar ago | 0

how to plot normalized column vs another colomn
must be missing something as you have it right there plot("your other column",i./max(i),'.') then you'd fit a line and e...

bijna 3 jaar ago | 0

How do I create an animation with a coloured sphere changing in time? (for climate modelling)
you can do something like this [x,y,z] = sphere(30); [sx sy]=meshgrid(-1:.01:1,-1:.01:1); I=3*sin(2*pi*2*sx)+cos(2*pi...

bijna 3 jaar ago | 0

How to upload an image to a GUI frame?
so i take it you have an axes frame that you've tagged as imagedisplay. i'm curious why with said function you don't get warnin...

bijna 3 jaar ago | 0

Repeating If statement after variable change
not sure what you mean by repeat first with SS(1)==# as it wouldn't do the first if statement but the lower elseif statement. i...

bijna 3 jaar ago | 0

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How do I piece together a 2-dim image using 3 given images, each representing R, G, B?
you should be using cat(3,red,green,blue) because you want to stack in the 3rd dimension. x = randi(3,3,3) x = ...

bijna 3 jaar ago | 0

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Legend for a graph displaying multiple runs
you can look into specifying which points/lines are plotted in the legend() help documentation. I made a quick example that y...

bijna 3 jaar ago | 1

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I need to create a 3 by 3 window and calculate mean within the window. This window is to move through the image. How can I do it?
I would take a look at the conv() and conv2() function. you would use something like [1 1 1;1 1 1;1 1 1]/9 to get mean. and the...

bijna 3 jaar ago | 0

How to make a 2D graph from text file
I can point out a few things. # if you look at M isn't that what you're trying to plot with A? as it should include both c...

bijna 3 jaar ago | 0

how to replace values of a matrix, if another matrix meet certain conditions?
i may be over simplifying it but doesn't the greater than (>) inequality just do it? A=magic(5) B=A>18

bijna 3 jaar ago | 1

Pulse train with duty cycle variable.
why not try something like this: t=0:per/1000:per-per/1000; %define period normal = zeros(1,numel(t)); normal(t<per*dut...

bijna 3 jaar ago | 0

Is there a way to remove the nested for loops from this segment of code? I'm trying to make the code generic so it can take in n-number of moment arrays.
to make it more generic you could do something like momentind = [1 1 1 1 1 1] cind = 1; while momentind(end)~=3;...

bijna 3 jaar ago | 0