I recently came across the Trading Toolbox in matlab and I was very excited to find out you can do automated trading with it. I read the documentation, which was pretty clear, a couple of functions to connect to a certain broker, some order functions and a disconnect function. What I couldn't find out though is how you can make sure that your code is run constantly, otherwise automated trading isn't possible since trades can only be made or closed once every time you run your code. That shouldn't be the case, the code should be repeated every second or minute for that matter. Does anyone know how this can be achieved?
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After searching for a veeery long time (more then 3 months) in all the main places where to get info and reading the datasheet of the chip I would like to ask the STM32 specialists inhere if there is a example for using the ADC maybe with DMA from the arduino IDE. I did see some incomplete parts inhere and for other compiler/IDE environments. But maybe i did not strike the good luck of finding the right info (that even i can understand) yet for what i need.
Your help is much appreciated.
I want to sample audio data, one channel 30KHz plus, 12 bits and each time 16 samples are taken an interrupt to handle the data that is in an array.
I have seen the pigOscope code (it uses analogread) and the info about analogread where there is stated this command is not meant for higher sampling speeds So that got me sort of into conflict with myself .... Who can break me out of my endless brainloop .....?;
Greetings ... Eric.
I have seen the pigOscope code (it uses analogread)
I wrote the Pig-o-scope code, with a lot of input from others at stm32duinocom and if you take the time to read the code, which I will grant you is somewhat simplistic, you will discover that analogRead is only used to trigger. The code uses DMA to do the high speed transfer.
I completely agree with the comment that you dont't need the Arduino IDE, you could "borrow" the DMA code and tailor it to your needs. However if you want a quick and dirty coding and prototyping environment, then there is nothing wrong with using the Arduino IDE. Take a trip to the stm32duino.com site, and you will see that I along with a lot of the other developers use the Arduino IDE, and Eclipse, and Atollic, and roll our own batch files, use vi, etc etc.
It all depends on what you are trying to do, and in many cases using the Arduino IDE gets you to working result a lot faster than learning an entire new IDE, just for one task.
But then again, I'm firmly on the side of vi in the vi/emacs wars, so what the heck do I know. Just don't use nano. ;¬)
I have a multiplayer project which has some forever loops with checking code inside of them.
The problem is, multiple computers might process this and change crabx or craby due to lag in the variables dvotes, uvotes, lvotes, or rvotes. Only one machine should change this, though.
This can be easily solved by giving each player an ID like many people do in SQL. I would just check if the ID is 1, and that would be the "operating machine". I would then do all of these checks on that one machine. It would do things a Scratch server would do if you could program it...
The problem with this is that there is no way to detect when a player leaves the game. There is no block that is called "on exit" or "on stop button pressed". How would I go about doing this? I have seen people have a button which people click to exit, but some people will not click it/not even see it.
Thanks in advance!
Option 1
I've never been especially successful with cloud data myself, but I've heard the theory on this before:
Essentially, each player gets a "counter". Their computer then constantly increases that counter. If the counter ever stops increasing (which will be detected by the other computers, who are all looking after one another), the project will know that the user has left and one of the computers will take care of removing their ID and other data.
Obviously, this is much easier said than done. (As I said, I've never gotten complex cloud data to work well for myself, but I've seen it done successfully and explained.)
Option 2
Alternatively, you might be better off taking advantage of this cloud api created by MegaApuTurkUltra. I find that stealing from others tends to be the best way of solving problems when it comes to code. ;)
I have been working at entering and sustaining periods of flow while working, and while researching the concept I came across this site which addressed the idea of sustaining flow in short bursts. The technique specifies that one sets a timer for 48 minutes in which they focus purely on their work, and when the timer runs out they spend 12 minutes doing whatever.
However, in the paragraph directly above that statement is a quote from Peopleware saying that it takes at least 15 uninterrupted minutes to enter a state of flow.
When reading that point, the 48 minute technique seemed counter-intuitive, since every 48 minutes you are "breaking" your flow, and once you start up again you have to spend 15 minutes going back into it, so you really only get (at a maximum) 33 minutes of "flow time". Obviously these quantities aren't necessarily rigid, but you get the idea.
My question is to those who have tried a timing technique similar to the one described. As I see it, the only justification for this technique is that it possibly reduces the amount of time it takes to re-enter that period of flow. Can anyone who has used this technique provide some clarification?
I've tried the Pomodoro Technique for a week or so. I didn't focus too much on the details of maintaining check lists of completed and interrupted sprints, but rather I started the day with the tasks that I wanted to do on that day, and went through them as best as I could using the 25-minute sprints and five-minute breaks.
The Pomodoro Technique suggests to use the breaks to relax, stretch your legs, grab a coffee, etc. I've noticed that activities like those that don't require a total focus shift and can be done on automatic don't break the flow, but rather helped me cleanse my mind and refocus my attention. It's as if you're allowing yourself to step away from the trees to survey the forest for a bit before diving back in.
I dropped Pomodoro after that short trial period because I found that in my case I got the most benefit from simply sitting down in the morning and writing down what I wanted to do on that day. Once the decision is made and the work is started I found that I fall into a natural rhythm of sorts. I work until I'm bored, frustrated, or interrupted, then I take a break and continue. I didn't find that time boxing my sprints added much value.
YMMV, but it's worth at least giving it a try.
A timer would be terrible for me, because it might go off and interrupt my train of thought at a critical moment.
For me, maximizing flow would begin by (1) first preventing forthcoming distractions (ie, making sure phone calls and other interrupts are disabled and that anything scheduled, like a meeting, is sufficiently far off there's no possibility of running into it), then (2) working on the problem at hand as long as I can, but all the while trying to recognize when I'm not making progress.
If I think I'm making progress, no matter how slowly, I just keep going as long as I can. But if I appear to be stuck or going in circles, I stop, and do something else instead, even if that something else is starting on a different problem. I let my subconscious dwell on the original problem, and once I have a feeling I feel fresh or curious enough to restart again, I do.
I was working on something for a client today when I found a way to break some functionality in our program.
(The code is really legacy code, it's been in development for about 10 years and I've only been working here for about a year.)
It didn't cause an error, or cause the program to crash, but if a user was using the program and duplicated the behavior I'm pretty sure they'd be holding up their "WTF?" flag.
In our program we have named fields (textboxes) and static text (labels) that can be linked with the textboxes. When the textbox is not filled in the label(s) that were linked to them disappear.
The functionality that I broke was, when you change the name of a textbox that already has one label or more linked to it, and save the file, without re-associating the one or more labels associated with the textbox, the formerly-associated labels appear when the textbox is blank.
Now my thinking on the matter is that a simple observer pattern could have solved this problem in the first place, but then I didn't write the code.
I was thinking that if I could dig up more situations like this with the guys in my shop, that maybe I could talk them into considering unit testing, decoupling, applying patterns where they are called for and the like.
So for this reason I was wondering if anyone had any tips for finding broken (but not error causing) functionality in any sort of app (web-based, desktop, etc...)
For an app to fail usability, it has to have a defined set of expected behaviors.
"Is this textbox SUPPOSED to do nothing when the enter key is pressed?" Maybe it is, maybe it isn't. I've seen apps where a tester/reviewer reports something that they ASSUME should work another way, when in actuality the client specifically asked that they DON'T want the form submitted on a return key press, but only a submit button click.
So basically you have to define proper behaviour before you can determine incorrect behavior.
Hire some testers.
If it has an interface, then one of my favorite unconventional test is putting 5-10 year old children in front of it. You'd be surprised what they can come up with (especially the younger ones). While this may sound like a joke, it isn't -- it really works, because children don't have the mindset of only going through "mindset" paths.
And yeah, children are the experts in "breaking things" xP.
Code inspections, i.e. reading the source code: if you had taken time to read/inspect the source code, looking for "smells" or even just looking for code whose behaviour you don't immediately understand and agree with, you might have been holding up your "WTF?" flag too.
Test, test, test.
Do unexpected things. Start doing one task and switch another to see if anything goes haywire. Use the back button when you're not supposed to. Open it in two windows. Let it time out.
Test in all browsers, especially IE.
You can find database connections/sessions aren't released by:
working out the minimum number of connections you need to do something
setting resource limits to that minimum number
ensuring one "run" of the scenario that should use exactly that number (and release it afterwards)
then run it again a few times... do you run out of connections?
I used to work in a company where programmers regularly used to forget to de-allocate db connections. The standard answer was to reduce the resource to a minimum to see if there's a leak - and to try to work out where it is by restarting the system and running different scenarios repeatedly.
The first hour of code review, with the first reviewer, will do the most to find quality problems. But here's the thing: You don't need to convince people of quality problems. You need to convince them of the value of fixing bugs, and of rewriting only when the present quality absolutely justifies it.
I've dealt with some seriously bad code in my time. But you can't just rewrite. You need a spec before you can even tell if the rewrite is an improvement.
Sometimes, you have to infer the spec from the code and then check it against some human somewhere. But by the time you've done that, you understand the code as written and are now better prepared to repair than to rewrite -- most of the time.
Repair proceeds by a process of small behavior-preserving modifications that render the spec more clear in the code. Then, when you find something that looks wrong, you don't just change it. You ask around until you find the person responsible for that decision, and you get them to show you where in the spec it says that behavior X is correct. (This conversation can take many forms.) If you're lucky, they'll tell you that behavior X is in fact incorrect, and then you've earned your pay.
assert()
Also unit testing with coverage analysis.
This is particular to the Visual Studio IDE, although it probably also applies to others:
During testing, always at some point run in the debugger with "Break when an exception is thrown" turned on.
This can often help expose exceptions which are incorrectly being silently caught and which represent bugs, but otherwise may not be evident.
Code reviews should always also include reviews of the unit test code.
The problem is that with ad-hoc testing it's impossible to know how much or how well a developer has tested their code. So, you're at the mercy of different developers definition of the word "done".
If you include reviews of the unit test code at the same time you review the production code you should have a good idea of whether the code is really complete; in that "complete" includes "tested". Not just "Hey, I'll throw it over the wall to the testers!".
I'm trying to get data from a server. Right now, I am polling the server every couple of seconds for the current values. I am wondering if it is possible to have Matlab get the data in real-time or if I am stuck with my current implementation. Has anyone done anything like this? If so, maybe you can tell me how you got started with it.
Any help would be greatly appreciated. Thanks!
If you're on Windows, you can listen to ActiveX (COM) events using REGISTEREVENT. You would need to provide an ActiveX control (servers might work too, I'm not sure) that triggers the event, which would invoke your MATLAB function.
Matlab timers work well for periodic events. You'll want to be careful about making sure your function executes in less time than the periodicity of the timer, though settings for the behavior when that doesn't hold do exist.