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Large Data in MATLAB: A Seismic Data Processing Case Study

version 1.0.1.1 (4.63 MB) by

These are the files used in the webinar on Feb. 23, 2011.

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You can watch the archived version of this webinar at http://www.mathworks.com/videos/large-data-in-matlab-a-seismic-data-processing-case-study-81792.html (recommended).
The demos show how to manage out of memory data using a memory mapped file and customizing the object for array indexing. This enables reuse of the memory mapped file inside functions or with parallel computing without needing to rewrite code or recreate the memory mapped file on each worker manually.
The data files are not inlcluded in this download. Read the README file to locate the public data sources on the internet.

The demo also shows how to speed up the solution of the wave equation (finite difference PDE) using a custom CUDA kernel. The relative speedup observed was around 1.6X.

The demos start with:
1 - and introduction to seismic analysis (Kirchhoff migration, reverse time migration)

2 - Large data extension of the functionality shown in (1) and parallel computing for speeding up the processing time

3 - GPU extension to (1) showing how to use a custom CUDA kernel to solve the wave equation compared to a MATLAB implementation (written in vectorized form)

Comments and Ratings (19)

I got this problem pls help.

Error using urlreadwrite (line 98)
Error downloading URL. Your network connection may be down or your proxy settings improperly configured.

Error in urlwrite (line 38)
[f,status] = urlreadwrite(mfilename,catchErrors,url,filename,varargin{:});

Error in setup (line 59)
urlwrite([url,'/',f{i}],f{i});

The url from where the setup.m retrieves the data has changed, so comment out the link below and use the amazonaws link instead. the SEG organization might have moved all their datasets on the amazon cloud instead of hosting them on their servers.

%url = 'http://software.seg.org/datasets/2D/2004_BP_Vel_Benchmark';
url='http://s3.amazonaws.com/open.source.geoscience/open_data/bpvelanal2004'

you can also use "curl" to download these datasets. If gunzip is failing, you probably have not retrieved the file correctly.

Abd Hafidz

aditya aries


I got problem while running setup.m

variable dx is undefined.

where can i find dat4gpu.mat?
please help

Panda Big

I got some problems and solved it bymyself.
qus1:variable dx is undefined
dx=12.5,dx is the reciver intreval

qus2:the variable wkrs is unused!(In the setup.m file),to calculate the travelTime takes a long time.How to let it run fast?

Hi, does anyone have the video that is linked in up above? I can't get it to run and I'd really like to be able to watch it to learn more about how to interpret seismic data using MATLAB.

cheng joylin

I got problem while running setup.m

variable dx is undefined.
there is variable named idx, so i put idx instead of dx and run the setup.m again but i got another error msg.
"error using *
inner matrix dimension must agree
problem in ray2d
T = T(iz,iz)*dx"

please help

Dawn Li

I met same problem as follows:

??? Error using ==> urlwrite at 140
Error downloading URL. Your network connection may be down or your proxy settings improperly
configured.

Error in ==> setup at 61
urlwrite(['ftp://seismic.seg.org/pub/datasets/2D/2004_BP_Vel_Benchmark/',f{i}],f{i});

I modified program as what you indicated as :

change the adress of the FTP site in line 61 urlwrite to:
'ftp://software.seg.org/pub/datasets/2D/2004_BP_Vel_Benchmark/'

The program accepted changes and new problem I met is:

Error using gunzip>gunzipwrite (line 184)
File "shots0001_0200.segy.gz" is not in GZIP format.

So, please tell me which gzip function I should use in gunzip(f([5:11,end]));?

Thank you very much.

Rafik

Rafik (view profile)

I got a problem whit my data : Could not locate file: vel_z6.25m_x12.5m_exact.segy
Error in migrateExample (line 13)
V = SegYFileReader('vel_z6.25m_x12.5m_exact.segy',true,false);

Sharad

Sharad (view profile)

BOUSSOUF

Great work Luis!
I got a problem whit my data when I used "parfor" in Linux! I got "Out of memory" error, even with a 4Gb RAM and 6Gb swap memory!

Jonathan

Very nice of Matlab to put out a complete suite of programs for seismic data processing!! Thanks!

salamay

build.m under /gpu fails as dat4gpu.mat cant be found.

The current version does not contain this dat file.

Please update.

Luis Lopez

William, change the adress of the FTP site in line 61 urlwrite to:
'ftp://software.seg.org/pub/datasets/2D/2004_BP_Vel_Benchmark/'

This should solve the issue.

William

setup.m fails with the following errors:

??? Error using ==> urlwrite at 140
Error downloading URL. Your network connection may be down or your proxy settings improperly
configured.

Error in ==> setup at 61
urlwrite(['ftp://seismic.seg.org/pub/datasets/2D/2004_BP_Vel_Benchmark/',f{i}],f{i});

>>

This is using MATLAB 7.12.0 (R2011a).

Todd Schultz

Excellent work! This is a great example of some of the options available to handle large data sets in MATLAB.

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