does anybody know how I can read mps file in miplib website? I downloaded them and opened them by ampl but it’s not clear what is constraints!!! In the top of the problems has been written : encoding-iso-8859-1 i don’t know what this mean??? I attached opened file !
MIPLIB problems are provided in (a low level) MPS format. Typically MPS files are fed directly into a solver. There is no good way to reconstruct a nice, indexed AMPL model from an MPS file (basically lots of the structure is lost). It should be possible to create some scalar AMPL representation of an MPS file, but that is of very limited value.
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How can I, using a function, library, whatever I have to, concatenate two .wav files? The input should be the absolute paths, and the output an audio file created and placed (not just played) somewhere, it doesn't really matter where.
I am writing a Mac command line application in XCode 6.
The .wav file format is a very simple format, consisting of the fixed header that defines the audio file's properties; namely the endian-ness, the number of channels, and the sampling rate. Its documentation is widely defined on the intertubes.
Off the top of my head I don't recall if any common library offers a convenient way to do this (it's worth looking through libsndfile's API documentation, for something that would fit the bill).
In any case, it shouldn't be too tough to read the headers of both WAV files, to check their format, and then create the output file. If both WAV files have the same endian-ness, number of channels, and sampling rate, the procedure is trivial, otherwise you will have to resample/remix at least one of the files.
There is a very simple, lightweight and mature open source C API library for reading-writing several common audio file formats. I haven't worked with it for a while, if I remember well, it has routines for opening a sound file for writing, seeking the end, appending data from another file and updating the header. I hope this can help.
I am working on a project which needs to deal with large seismic data of SEGY format (from several GB to TB). This data represents the 3D underground structure.
Data structure is like:
1st tract, 2,3,5,3,5,....,6
2nd tract, 5,6,5,3,2,....,3
3rd tract, 7,4,5,3,1,....,8
...
What I want to ask is, in order to read and deal with the data fast, do I have to convert the data into another form? Or it's better to read from the original SEGY file? And is there any existing C package to do that?
If you need to access it multiple times and
if you need to access it randomly and
if you need to access it fast
then load it to a database once.
Do not reinvent the wheel.
When dealing of data of that size, you may not want to convert it into another form unless you have to - though some software does do just that. I found a list of free geophysics software on Wikipedia that look promising; many are open source and read/write SEGY files.
Since you are a newbie to programming, you may want to consider if the Python library segpy suits your needs rather than a C/C++ option.
Several GB is rathe medium, if we are toking about poststack.
You may use segy and convert on the fly, you may invent your own format. It depends whot you needed to do. Without changing segy format it's enough to createing indexes to traces. If segy is saved as inlines - it's faster access throug inlines, although crossline access is not very bad.
If it is 3d seismic, the best way to have the same quick access to all inlines/crosslines is to have own format - based od beans, e.g 8x8 traces - loading all beans and selecting tarces access time may be very quick - 2-3 secends. Or you may use SSD disk, or 2,5x RAM as your SEGY.
To quickly access timeslices you have 2 ways - 3D beans or second file stored as timeslices (the quickes way). I did same kind of that 10 years ago - access time to 12 GB SEGY was acceptable - 2-3 seconds in all 3 directions.
SEGY in database? Wow ... ;)
The answer depends upon the type of data you need to extract from the SEG-Y file.
If you need to extract only the headers (Text header, Binary header, Extended Textual File headers and Trace headers) then they can be easily extracted from the SEG-Y file by opening the file as binary and extracting relevant information from the respective locations as mentioned in the data exchange formats (rev2). The extraction might depend upon the type of data (Post-stack or Pre-stack). Also some headers might require conversions from one format to another (e.g Text Headers are mostly encoded in EBCDIC format). The complete details about the byte locations and encoding formats can be read from the above documentation
The extraction of trace data is a bit tricky and depends upon various factors like the encoding, whether the no. of trace samples is mentioned in the trace headers, etc. A careful reading of the documentation and getting to know about the type of SEG data you are working on will surely make this task a lot easier.
Since you are working with the extracted data, I would recommend to use already existing libraries (segpy: one of the best python library I came across). There are also numerous free available SEG-Y readers, a very nice list has already been mentioned by Daniel Waechter; you can choose any one of them that suits your requirements and the type file format supported.
I recently tried to do something same using C++ (Although it has only been tested on post-stack data). The project can be found here.
My line of work requires the use of DICOM files. Each DICOM file constitutes many .dcm files in a single directory. I am required to send these files over the network, a process which is somewhat so due to the massive size of the files.
I am also a programmer and I was wondering what is the ideal way to compress such files? I'm talking about a compression that will be made on the local computer and later decompressed on the destination computer (namely the compression is solely for speeding up the over-the-network transfer of the file). Is there a simple way to crop the DICOM files? (the files contain imaging of an entire head, whereas I'm only interested in a small part of the head).
Thanks!
In medical context, lossy compression is somewhere between not encouraged and forbidden. If you'd insist on cropping existing datasets the standard demands you to form at least new image & series UIDs. The standard does allow losless compression in the form of jpeg2000, but it is quite rare - if I had to bet I'd say your dataset is uncompressed altogether.
In my experience it is significantly better to compress a medical dataset as a solid archive - that is, unify all the images into a single stream. This makes a lot of sense, as there is typically a lot of similarity between nearby images and this is the way to take advantage of that similarity (a unified compression dictionary). This is available as a command line option both to rar and gzip compressors.
Solution:
gdcmconv --jpeg uncompressed.dcm compressed.dcm
or for better compression ratio:
gdcmconv --jpegls uncompressed.dcm compressed.dcm
See:
http://gdcm.sourceforge.net/html/gdcmconv.html
I would also recommend against lossy compression, you would need to be a DICOM wizard to do it properly (see derivation mechanism in the DICOM standard). I would also recommend against cropping the image (you would need to regenerate UIDs, get the Frame or Reference updated...)
HTH
You could use something simple like lzma compression on one end to pack up the files and send them over. This is the easiest solution, since you can grab something like gzip and pack/unpack the files easily programmaticly. This may help considerably, because modern computers prefer transmitting/receiving one large file over many small files (a single 1GB file will transfer much faster than 10000 100KB files).
As for actually reducing the aggregate size, each .dcm file is probably a slice (if you're looking at something like MRI or CT data), and the viewer you are using reconstructs the slices into the 3d image. Cropping them isn't impossible, but parsing the DICOM format is a bit tricky. I'm not aware of any free programs that will help you parse the DICOM files, but I haven't looked for some time.
Since DICOM is a container format, the image data you are after is usually stored in a common format (such as JPEG), so if you are able to grab the relevant part of the file to extract the image data, you can use any of the loads of image processing tools available to crop the image to whatever dimensions you choose.
We have a compression router called "DICOM Shrinkinator" that can do this as it transmits the study to PACS:
http://fluxinc.ca/medical/dicom-shrinkinator/
Greetings all,
I am currently a rising Sophomore (CS major), and this summer, I'm trying to teach myself C++ (my school codes mainly in Java).
I have read many guides on C++ and gotten to the part with ofstream, saving and editing .txt files.
Now, I am interested in simply importing an image (jpeg, bitmap, not really important) and renaming the aforementioned image.
I have googled, asked around but to no avail.
Is this process possible without the download of external libraries (I dled CImg)?
Any hints or tips on how to expedite my goal would be much appreciated
Renaming an image is typically about the same as renaming any other file.
If you want to do more than that, you can also change the data in the Title field of the IPTC metadata. This does not require JPEG decoding, or anything like that -- you need to know the file format well enough to be able to find the IPTC metadata, and study the IPTC format well enough to find the Title field, but that's about all. Exactly how you'll get to the IPTC metadata will vary -- navigating a TIFF (for one example) takes a fair amount of code all by itself.
When you say "renaming the aforementioned image," do you mean changing metadata in the image file, or just changing the file name? If you are referring to metadata, then you need to either understand the file format or use a library that understands the file format. It's going to be different for each type of image file. If you basically just want to copy a file, you can either stream the contents from one file stream to another, or use a file system API.
std::ifstream infs("input.txt", std::ios::binary);
std::ofstream outfs("output.txt", std::ios::binary);
outfs << insfs.rdbuf();
An example of a file system API is CopyFile on Win32.
It's possible without libraries - you just need the image specs and 'C', the question is why?
Targa or bmp are probably the easiest, it's just a header and the image data as a binary block of values.
Gif, jpeg and png are more complex - the data is compressed
I've seen a lot of games use something similar to a .DAT file or a specific file type that the game has for itself. I'm just beginning with C++ and DirectX and I was interested in keeping my information in something similar to a .DAT.
My initial conception was that it would hold information on the files you wanted to store within the .DAT file. Something similar to a .RAR file. Unfortunately, my googleing skills did not help me in finding the answers.
Right now I'm simply loading textures and sound files from a folder called Data.
EDIT: While I understand that .DAT is short for data, and I've found that a .DAT file generally contains any assortment of information, I'm still unsure about how to go about doing something as packing images and sound files into any type of file and being able to read them.
I'm not sure about using fstreams to achieve my task, however I will look into streams related to storing data and how to properly read from that data. Meanwhile if anyone has another answer to offer based on this new information, it would be appreciated.
EDIT: Thanks to the answers, I stumbled across a similar question on stackoverflow and felt I'd share it here. Combining resources into a single binary file
I don't think there is really such thing as .dat file format. It's short for "data," and different applications just put in some proprietary stuff in it and call it ".dat." You can read up on fstream classes to do file IO in C++. See Input/Output with files.
What you then do is make up your own file format. For example, first 4 byte is int that indicates the number of blocks in the .dat and for each block, you have 4 byte indicating the length of each block, 4 byte indicating the type of the block, the variable length data itself .. something like that.
DAT obviously stands for data, and there is no real or de facto standard on what that extension actually refers to. Your decisions on the best file formats should be based on technical considerations, not pointless attempts at security through obscurity.
Professional games use a technique where they put all the needed resources (models, textures, sounds, ai, config, etc) zipped/packed into a single file thus making it faster to manage, harder to change (some even make use of a virtual filing system from what's inside the data file). Now, for what's inside the file is different depending on the needs of the game and the data structures that you use.
If you're just starting into gamedev, i recommend you stick with keeping all you assets separate and don't bother too much about packing them into a single file.
Now if you really want to start using a packed format here's a good pointer:
Creating a PAK File Format
Here's a link which claims that .dat is a movie format, 'DAT' being short for Digital Audio Tape.
I'm not sure I believe the link, but I do remember something about a Microsoft supported format called DAT, from long ago, when I used an earlier version of Windows.
It makes more sense as a logical extension for a DATA file of some kind.
.dat, as others have said, is literally just a data file. In reality, the file extension means nothing other than association with a program. For example, I could make a word processor that saves all the documents with the .mp3 file extension. These files wouldn't be playable in any media software, but the software might try. File extensions are used to help programs know what types of files they can and cannot open--however those rules don't have to be followed.
Anyway, you can dump any sort of information to a file. Programmers/software writers will often choose .dat as the extension of that file because it has become the standard to signify 'this file just holds a ton of data' and that the data doesn't necessarily hold any standardized headers, footers, or formatting.
A dat file could really contain anything. It might be as simple as a zip archive with the extension changed, or it could be a completely custom file type. If you're just starting out, you probably don't want to write your own file format, although doing so can be fun and educational. If you want to encapsulate your data files into some kind of container, you should probably go with a zip, paq, or maybe tar.gz.