I have a batch program written in Matlab, which will be deployed to a production system by packaging it using the Compiler Toolbox.
When starting the program, multiple config and data files will be loaded, where the first config file contains paths and filenames for the other files to be loaded. I have a logger in the form of a hidden global object, and its static functions allow to add to the log. Every line will be immediately written to file (Performance does not matter, but reliable logging does!).
I want to dynamically specify the location of the logfile in a text file, but I don't know where I should put that file. In the classic interpreter mode, the wd of the constructor within the loggers' classdef seems to be directory where the file is saved, but I don't really understand why.
What is a reliable way of finding a textfile in the same directory as my classdef in a Compiler-packaged program using relative paths?
Thanks!
Related
For this project we have been given code, and will be changing some inputs and assumptions. Thus, I already possess the original codes, but just changing all the creator's file paths to match my own computer is yielding me a lot of trouble. The following, and many variations of, continually yield errors.
load \Users\myname\Library\Documents\...
The error is
Error using load
'Unable to read file
\Users\myname\Library\Documents...'.
No such file or directory.
My files are stored in my Documents. Another person in my group on windows has used
load C:\Users\hisname\Desktop\...
Is there something I'm missing in my line, similar to the C drive but on Mac? Is my code just completely wrong, I'm able to load files in R quite easily, but Matlab is posing a huge hurdle. I have no experience with Matlab and have been asked simply to run this code.
On the Mac, path components are separated by /, not \. Thus, you should type
load /Users/myname/Documents/filename.mat
You can use the location bar at the top of the command window to change to the directory where your file is located, and then you can type
load filename
to load filename.mat.
Also, are you sure you have a Documents directory under Library? Why?
To run code from a file called "my_file.m", than just open your Matlab and type run my_file.m. This will run your script in the Command Window.
The load function is used, if you want to load a .mat file. These are normally files, where variables from your workspace are stored.
For example, in my main.scm file I have (load "util.scm"). util.scm is a file in the same folder as main.scm. Both files are located in ~/documents/myproject/.
Now when I'm in this directory, and I run $ chez-scheme main.scm everything works fine. However, if I'm in my home directory and run $chez-scheme documents/myproject/main.scm it complains, not being able to find the file util.scm. I suppose this is the case because the current directory was my relevant home directory, and as such util.scm is indeed not there, it is actually in documents/myproject/. That being said, I'm used (in other languages) to the functionality of looking these paths up relative to the file containing the instruction to import, and I'd like to have that here as well. I've tried prefixing it by ./ or defining the file as a libary and doing (import (util)) but none of it works outside of documents/myproject/. Is there any way to get this to work as I intend it to?
I assume this is Chez-Scheme-specific. If not I'd prefer an answer that is implementation-neutral.
load is kind of awkward in R5RS since the report states that system interfaces are off topic in the report, but they include load which is a half hearted solution. The report does not say if the load is relative to the current directory or the file the load form originates from so in order to be portable I guess you are required to run your script from the current directory and have your loaded file relative to both.
Since Chez Scheme implements R6RS load is not really the right form to use. R6RS removed load in favor of libraries. You should make your file a library and consult how to install it. In some systems that is just placing the files in the right path, adding library location in configuration or running install script. How one uses the library is the same in all implementations, by using import.
According to Chez documentation you can pass --libdirs to it to give it one or more paths to consider for loading libraries. You can see the paths it scans by evaluating (library-directories)
There are several different ways to accomplish what (I think) you are trying to do, but eventually they all boil down to letting Chez know where to look for things. When given relative paths, include and load use the source-directories parameter to search for the requested file. Libraries have their path automatically prepended to source-directories while they are being loaded or compiled, so if your main.scm were a library definition then it would find util.scm as you expect.
However, it sounds like main.scm isn't a library, it's a top-level program. Unfortunately, Chez doesn't have a command line option to set the source-directories like it does for library directories. That leaves you with a bit less flexibility. Any of the following will work:
Make util.scm a library and invoke Chez with the --libdirs option to let it know where to look for libraries.
Set source-directories and load main.scm from inside the REPL rather than from the command line.
Write a wrapper shell script that does the above by echoing the commands into scheme so you don't have to type it yourself. (Only suitable if you don't also need to then type into the scheme session).
Write a wrapper shell script that cds into your project directory before running scheme (and presumably cds back to the original directory when it's done).
Suppose two different Matlab users share a computer and they each want to be able to save and load their own Matlab paths. (Or, a single user wants to use different paths at different times.) What's the easiest way to handle this?
Should there be multiple pathdef files? Alternatively, should they each have a script that calls restoredefaultpath and then uses addpath to add new paths?
You can use the startup.m file for that.
When starting up, Matlab executes the file matlabrc.m, which is the master startup file, and is common for all users. Among other things, this file
Sets the first entry of the path as the user-folder of the current user, that is, the user that started Matlab. (This is done by calling pathdef, which in turn calls userpath); and then
Looks for a startup.m file in the path, end executes if it exists.
Therefore you can place a user-specific startup.m file in each user's folder, and Matlab will run the appropriate file depending on which user started Matlab. In that file you can set the path on a per-user basis, and do other user-related stuff.
Hi im new to programming, how do i import a .txt file? My code cant find the file, is there any specific directory it has to be put into?
My code:
object Zettel01 extends App {
import scala.io.Source
object Suchtest {
val gesch = Source.fromFile("DieUnendlicheGeschichte.txt").getLines()
for (w <- gesch) println(w)
}
}
I have tried different code but the problem is always the same, i cant find the .txt file...
Thanks in advance for any help
Flurry1337
Every Scala program that you run on your computer is ultimately a java process. This process will have a "working directory", just as every process on your computer does. By default, the working directory is the working directory of the process that started it, that is, the current directory of the shell or command-line interpreter at the time when you started your program.
Now, that means it is important to know how exactly you start your program. If you are using a command line and start your program in the fashion of java MyCoolProgram, then the current directory of the shell will become the working directory of the program. If you use an IDE like Eclipse or IntelliJ IDEA, those typically use the project folder of your IDE project as the working directory of the process that they start.
There is a simple way to find it out quickly: You can always print out the result of new java.io.File(".").getAbsolutePath(). This will print the full path to the working directory. For example, you can write a little Scala program like this:
object PrintWorkingDirectory extends App {
println(new java.io.File(".").getAbsolutePath())
}
and start it. On the console, you should find the full path of the program's working directory. If you put a file named "DieUnendlicheGeschichte.txt" in this directory, your program will find that file under exactly that file name.
Of course, you don't have to dump all your files into that one directory. You can make subdirectories in order to organize your files better. For example, you might put your file in a path like "resources/text/DieUnendlicheGeschichte.txt".
Finally, I would like to point out that there is also a different way to associate resource files with your program, and to load them. The idea is that you put the code (class files) as well as resources like texts, images, CSV files, XML files and the like into one big file. This would be a JAR file. You can then use ClassLoader to access resources inside the JAR file by a URL.
Explaining that process in detail is out of scope for this question; this is just dropping a couple of buzzwords that you (or other readers) can search for in case they want to look up a more elaborated process.
System.getProperty("user.dir") also tells you the working directory.
Today I stumbled upon this thread:
http://www.mathworks.com/matlabcentral/newsreader/view_thread/112560
The question is basically how to make Matlab read your startup.m file regardless of where
you start your matlab session.
One of the solutions offered was:
One solution would be to ask the system administrator to add a few lines
to "matlabrc.m" that adds some pre-determined folder in the user's home
directory to the MATLAB path (say, ~/.matlabstart). Then each user can
have their own "startup.m" file inside this folder.
What I ended up doing in my system (OS X) was to add a startup.m file in:
/Applications/MATLAB_R2011a.app/toolbox/local/
In this startup.m file I added:
if exist([getenv('HOME') '/.matlabrc/startup.m'])
run([getenv('HOME') '/.matlabrc/startup.m']);
end
That way users have the option of creating the hidden folder ~/.matlabrc and inside it they can put the file startup.m. In this startup file they can tell matlab what to execute whenever they start Matlab regardless of the directory where they started it. An example of what I added to my own personal startup.m file is
addpath(genpath('/Users/jmlopez/matlabcode/'))
Now I can add as many folders inside that directory and all of them will be added
to the path every time I start Matlab automatically without having to modify the path.
The question is: Did Matlab already provided a special file like the one I created or did I just go through all this trouble to accomplish what I wanted? If the answer is the second option I gave, then, why doesn't Matlab provide this? It is such a pain in the ass to add directories to the Matlab path whenever you do not have admin permissions and I do not want to carry my startup.m file to every directory I go to. Can someone shed some light into this please?
You can save the pathdef file (which stores all the paths you add) to a custom directory. The problem however is that when matlab starts, it doesn't automatically know which custom directory you used in the previous session.
But that's where the MATLABPATH environment variable comes in. Because this allows to set the matlab starting path yourself. In linux this is simply done by setting this environment variable MATLABPATH before starting matlab (from a terminal / in your .bashrc / ...)
export MATLABPATH=$HOME/.matlab
This way you can let all users have their own pathdef file, which solves the problem of having to add them manually at startup.
EDIT
I tested out if adding startup.m to that MATLABPATH directory worked, ie: does matlab run that startup file? ... and it does. I think it doesn't work for you, because there is another startup.m file in some other (higher priority) directory (probably matlabroot), so that gets precedence. My only startup file is in MATLABPATH, so there is only one choice.
EDIT2
Nope, I added startup to matlabroot directory, and still my own startup file in .matlab gets run. Are you sure you set the MATLABPATH correctly before you started matlab?