I have the following code which downloads a CSV file from a link and then saves it as a formatted file:
urlwrite('http://xweb.geos.ed.ac.uk/~weather/jcmb_ws/JCMB_2013_Sep.csv','Weather Data.csv');
data= readtext('Weather Data.csv');
I want to download download this file every 5 minutes. The updated data from the file is used in other parts of my script so I also want those calculations and other parts of my program to be automated every 5 minutes with the change in new file information.
The timer feature in matlab calls a function and i'd rather do it as a loop format because my calculations aren't already saved as specific functions.
How can I achieve this as some sort of loop or timer?
The simplest way might be to put in a pause command, pause(t) pauses the script for t seconds, so you could have
while(1)
tic
urlwrite('http://xweb.geos.ed.ac.uk/~weather/jcmb_ws/JCMB_2013_Sep.csv','Weather Data.csv');
data= readtext('Weather Data.csv');
% run the rest of the code that you need to run on the data you have downloaded
T=toc;
pause(300-T)
end
You can terminate the loop by pressing ctrl+c, which will stop the code.
Hope that helps
Related
I want at the end of my program to get the values stored at certain variables and append them to a file let's say "result". I am going to run it several times (for different parameters) at night and then check results in the morning.
Basically, I am looking for something similar to redirection in linux (>>) for matlab.
I am using the diary function to store the whole messages from my program and i want to keep those for verifying later.
But here what I want is just some specific values. So how to do it?
It does not necessary have to be in the same file. If I can get each result in a separate file, that is ok too.
You can use a combination of diary and any function which can append data to a text file, but you have to turn off diary before writing. A short example using save
f='example.txt'
diary(f);
for ix=1:10
disp(ix);
diary off %diary off to flush
save(f,'ix','-append','-ascii')
diary(f);
end
Instead of save you can also use fprntf or dlmwrite
I'm using MATLAB and calling an .exe via the system command.
[status,cmdout] = system(command_s);
where command_s is a command string that is formatted earlier in my script to pass all the desired options to the .exe. The .exe would normally write to a .csv file via the > redirection operator in Windows/DOS. Instead, this output is going to cmdout where I use it later in the MATLAB script. It is working correctly and as expected. I'm doing it this way so that the process just uses memory and does not write a very large file to the disk, which would then have to be read from the disk and then deleted after I'm done with it. In the end, it saves a .mat file that's usually in hundreds of KB instead of 10s/100s of MBs as the .csv file would be (some unneeded data is thrown out in the end).
The issue I'm having is since I'm dealing with large files, the executable can take a significant amount of time. I typically have to wait about 2 minutes after executing this command. In the meantime, I have no feedback to know it is progressing and that my system hasn't froze. I know I could add the & symbol to the end of my string, command_s, and run MATLAB code while this is running in the background (or asynchronously as some would say), but that brings up an external window AND makes cmdout empty - so I cannot use the output - forcing me to sit there for 2 minutes wondering each time it executes.
Is there any way to run in the background AND get the stdout from the command?
Maybe you could try system(command_s,'-echo')?
I am working on CATScript in optimization of a part.
When I run the script everytime it shoud provide numbers in ascending order.
For example if I run the program for the first time it should provide the output as " 1 "
and if I run the program again it shoud provide the output as " 2 " and so on.
I am stuck with this and I could not figure out th logic that we have to use here.
Looking forward for your help.
Thank you!!
An option (matlab based) could be to save a counter variable to a .mat-file at the end of the script, which is then loaded again at the beginning of the script.
That would allow you to keep track of how many times the script have been run.
In CATIA if it is being run multiple times on the same part/product, you could add a hidden, integer parameter to the specification tree and increment it each time the macro is run.
Another, more generic way would be to create a text file on the user's local and update the number in the text file.
Is there any easy way to set a Matlab callback to execute a function whenever a specific file is modified? (I have a C++ program logging data and I want to run a Matlab script over that data everytime I execute the C++ program).
All I saw is that with FileInfo = dir('data.txt') I can get the date and create a script which is testing all the time if the last modification time has changed, but I do not like that solution.
I have a .csv file which is appended with 3 new values in the row below the previous set:
dlmwrite('MyFile.csv', [MyValue,MyValue2,MyValue3], '-append');
This happens every minute. It happens indefinitely because of a timer i.e it accumulates data over time:
How can I continually copy over the 60 most recent sets of values from the file and store them in a new csv file, say MyFile2.The row number of the .csv file is increasing by 1 with every minute. i.e 60 values stored in 60 minutes but I may have 100 values and want to extract the latest 60 for another file.
Image of the CSV file - 2nd column is time in HOURS:MINUTES without the : separator (ignore the lapse in time between rows 38 and 39 or any lapses elsewhere):
Note: MyValue is added to the file every minute because the script is run every 60 seconds from another script. I.e there is no internal timer in the main script:
Period = 60; % Update period in seconds
tim = timer('Period', Period, 'ExecutionMode', 'fixedRate',...
'TimerFcn', 'TESTINGFINAL');
start(tim)
stop(tim)
runtmp = fullfile('MyScriptLocation','MyScript');
run(runtmp);
If you want to do this continuously while running I'd suggest some sort of circular buffer arrangement so you always have the last 60 values in memory. This will be easier than trying to work out the current length of your continuously logging file. Basic idea (minus the actual timing code):
% initialising buffer
MyValue1 = zeros(60,1);
while true % for certain values of true
% these go once a minute
mv1 = myfunc1(inputs);
MyValue1 = [MyValue1(2:end); mv1];
dlmwrite('MyFile.csv', [mv1], '-append');
% this goes less frequently, I presume
filename = [datestr(now,30),'.csv']; % dynamic filename
dlmwrite(filename, MyValue1);
end
This way you have both your continuously logging file (updated every minute), and a series of smaller files containing what were the last 60 values at the time they were written (updated hourly, or on some other trigger, as required).
With your timer, one way of doing this would appear to be to keep a simple counter of how many times the acquisition script has run and then use the mod function to check for when this hits a multiple of 60.
This is not a full answer, but I do have an idea if I understand you correctly. This means you probably want to run Matlab 24/7? Or at least non-stop for a certain amount of time? If so, you could try out the command clock, it shows and stores the system time. In your case
time=clock;
where
time(4) holds the hour. So as soon as this parameter changes, you should open your .csv file and save the last 60 values.
However, doing it this way I think is highly energy-consuming. And sadly Matlab does not have a sleep command like for example Unix does, so maybe it would be interesting to look into running this program in another programming language?
Please provide me with comments and feedback since I see that this is not a complete answer (yet)!