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Mishal Mohanlal
Mishal Mohanlal
Last activity 2023 年 11 月 17 日

Hi Guys
Posting this based on a thought I had, so I don't really ahve any code however I would like to know if the thought process is correct and/or relatively accurate.
Consider a simple spring mass system which only allows compression on the spring however when there is tension the mass should move without the effect of the spring distrupting it, thus the mass is just thrown vertically upwards.
The idea which I came up with for such a system is to have two sets of dfferential equations, one which represents the spring system and another which presents a mass in motion without the effects of the spring.
Please refer to the below basic outline of the code which I am proposing. I believe that this may produce relatively decent results. The code essentially checks if there is tension in the system if there is it then takes the last values from the spring mass differential equation and uses it as initial conditions for the differential equation with the mass moving wothout the effects of the spring, this process works in reverse also. The error which would exist is that the initial conditions applied to the system would include effects of the spring. Would there be a better way to code such behaviour?
function xp = statespace(t,x,f,c,k,m)
if (k*x(1)) positive #implying tension
**Use last time step as initial conditions**
**differential equation of a mass moving""
end
if x(1) negative #implying that the mass in now moving down therefore compression in spring
**Use last time step as initial conditions**
**differential equation for a spring mass system**
end
end
The Flipbook contest is currently in full swing! It's been truly inspiring to see the incredible artwork you've all created using MATLAB! Checkout the gallery page if you haven't already.
We have some exciting news for our contestants today! In order to allow for more complex and unique creations, we've increased the MATLAB Evaluation timeout limit from 55 to 235 seconds!! So, don't hold back! Feel free to throw in those extra intricate lines of code without worrying about timeouts.
To all those already participating, we commend your efforts and encourage you to keep pushing your boundaries. And remember, there's always room for more. So, why not invite your friends and fellow MATLAB enthusiasts to join in the fun?
See the latest addition to the contest from @Cleve Moler, the creator of MATLAB!
We also encourage everyone to engage in the contest discussions channel. Share your experiences, insights, and feedback about this contest. Your contributions enrich our community and help us improve future contests.
Looking forward to seeing more and more entries in coming weeks!
We reached the 100 animations milestone in less than 3 days! We are thrilled to see so many creative entries and talented members learning from each other.
Note that this contest is not just for experts. People with all skill levels can participate, improve their MATLAB skills, and have fun!
We have created new resources and tips for you to get started.
  1. Contest introductory video. The 3-minute video provides you with a quick introduction to how the contest works and how to create a simple animation.
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Check out our 100th animation by Tim. Isn't it amazing?
We look forward to seeing more of you joining us and having more fun!
Seeing a colleague make this mistake (one I've had to fix multiple times in other's work too) makes me want to ask the community: would you like the awgn() function/blocks to give the option for creating a SNR at the bandwidth of the signal? Your typical flow is something like this:
  • Create a signal, usually at some nominal upsampling factor (e.g., 4) such that it's now nicely over sampled, especially if you're using a RRC or similar pulse shaping filter.
  • Potentially add a frequency offset (which might make the sample frequency even higher)
  • Add AWGN channel model for a desired SNR
  • Put this into your detector/receiver model
The problem is, when someone says, "I'm detecting XYZ at foo SNR," it should not magically improve as a function of the oversample. The problem isn't that awgn() generates white noise, that's what it's supposed to do and the typical receiver has noise across the entire band. The problem is that SNR is most properly defined as the signal power over the noise power spectral density times the signal's noise equivalent bandwidth. Now I looked and there's no handy function for computing NEBW for an input signal (there's just a function for assessing analysis windows). In practice it can get a bit tricky. The occupied bandwidth or HPBW are often close enough to the NEBW, we're usually not haggling over hundredths of a dB. So, in my not so humble opinion, the "measured" flag for awgn() should give an option for bandwidth matching or at least document the behavior better in the help page. All too often I'm seeing 3-6 (or worse) dB errors because people aren't taking the signal's bandwidth into account.
Unlike last year's contest, there are some new technologies this year that might offer some advantages. Namely generative AI's like ChatGPT, Bard, etc. Not to be excluded, MathWorks just launched the AI Chat Playground :)
The 2023 community contest - MATLAB Flipbook Mini Hack - starts today on Nov. 6th!
Participants across all skill levels are welcome to join! You can participate by creating a new animation or remixing an existing one with up to 2,000 characters of MATLAB code.
Contest Tips:
  1. Before you start, we highly recommend you check out the two examples - Bouncing and Spinning - to understand how the contest works.
  2. Share your thoughts, ask questions, or connect with others in our contest discussion channel.
Note that the first week (Nov. 6th, 2023, ~ Nov. 12th, 2023) is for creating entries only. Voting does not begin until the second week.
We look forward to seeing your creative work. Let the contest begin!
Image Analyst
Image Analyst
Last activity 2023 年 10 月 31 日

Just in time for Halloween.
Share your fun photos in the comments!
Julian
Julian
Last activity 2024 年 2 月 5 日

I know the latest version of MATLAB R2023b has this feature already, put it should be added to R2023a as well because of its simplicity and convenience.
Basically, I want to make a bar graph that lets me name each column in a basic bar graph:
y=[100 99 100 200 200 300 500 800 1000];
x=["0-4" "5-17" "18-29" "30-39" "40-49" "50-64" "65-74" "75-84" "85+"];
bar(x,y)
However, in R2023a, this isn't a feature. I think it should be added because it helps to present data and ideas more clearly and professionally, which is the purpose of a graph to begin with.
Matt J
Matt J
Last activity 2024 年 3 月 1 日

Would it be a good thing to have implicit expansion enabled for cat(), horzcat(), vertcat()? There are often situations where I would like to be able to do things like this:
x=[10;20;30;40];
y=[11;12;13;14];
z=cat(3, 0,1,2);
C=[x,y,z]
with the result,
C(:,:,1) =
10 11 0
20 12 0
30 13 0
40 14 0
C(:,:,2) =
10 11 1
20 12 1
30 13 1
40 14 1
C(:,:,3) =
10 11 2
20 12 2
30 13 2
40 14 2
Image Analyst
Image Analyst
Last activity 2023 年 11 月 10 日

Wait for Walter, the rest of us are mere users.
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

MATLAB Training
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

MATLAB Training
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

Mathworks tech support
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

Stand Back. I'm going to try MATLAB.
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

Embarassed by Walter Roberson
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

I use MATLAB.
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

MATLAB Reloaded
Image Analyst
Image Analyst
Last activity 2023 年 10 月 16 日

MATLAB Men