MohidWiki - User contributions [en]

Cvs

2007-06-26T17:26:16Z

192.168.20.110: /* Remote cvs from windows */

[[cvs]] is similar to [[svn]] but is older.

== Download and install cvs ==
=== Linux ===
[[cvs]] comes natively installed in nearly every linux distro.

=== Windows ===
Grab the binary [http://www.nongnu.org/cvs/ here]. Extract it into a folder that is listed in the PATH variable. Download and install this [ftp://gd.tuwien.ac.at/utils/shells/ssh/SSHSecureShellClient-3.2.9.exe ssh].

== Creating a new single-user repository ==

> mkdir ~/cvsroot
> chmod -R 700 ~/cvsroot
> export CVSROOT=~/cvsroot/CVSROOT
> cvs init

== Importing a folder or module into a repository ==
Make sure that the environment variable ''CVSROOT'' is defined,
> cd moduledir
> cvs import modulename longname v_1
Edit the log entry with information about the context of the module you are importing then save and ext the text editor.

== Checking out a module from a repository into a local repository ==
Make sure that the environment variable ''CVSROOT'' is defined,
> mkdir sandbox
> cd sandbox
> cvs checkout modulename

=== Remote cvs from windows ===
$ set CVSROOT=:ext:guillaume@nfist.ist.utl.pt:/users/left/guillaume/cvsroot
$ set CVS_RSH=ssh2
$ cvs checkout modulename

NOTE: Can't seem to make it work ...

== Commiting a module ==
Make sure that the environment variable ''CVSROOT'' is defined,
> cd sandbox
> cvs commit
Edit the log entry with information about the context of the module you are commiting then save and ext the text editor.

== External References ==
*[http://en.wikipedia.org/wiki/Concurrent_Versions_System CVS wikipedia]

[[Category:Technology]]
[[Category:Linux]]

Index

2007-06-26T09:27:11Z

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#REDIRECT [[Special:Allpages]]

Hyperslab

2007-03-27T14:02:06Z

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Hyperslab is the technical term when one refers to a generic subset of a [[netcdf]] variable.

Fetch

2006-10-10T18:47:08Z

192.168.20.110:

Fetch can be described as the length of the wind action. In a certain point, fetch can be seen as the direct distance, in the direction of the wind and on the surface of the water, between this point and the point where the wind effect started to take place.
In areas where the fetch is not restricted (e.g. open sea), there is a dominant fetch and small changes in wind direction don’t significantly change fetch length or the direction of the generated wave. On the other hand, for wind directions parallel to the shore and mainly for lakes, lagoons or estuaries, a small variation in the wind direction can generate significant changes in the wind’s length of action. In these areas there is not a predominant direction for fetch. In order to calculate the effective fetch it is then necessary to take into account the local morphology of the study area considering several directions, each one with a different weight. Thus, for the same wind direction, a point with more obstacles in the near directions has assigned a smaller fetch than a point with more water length in the same directions.
[[Category:Science]]

2jpeg

2006-10-10T18:45:24Z

192.168.20.110:

[[2jpeg]] is a nice little windows command line utility that converts other graphical file formats such as bitmap, gif and png to the jpeg format. It also allows some rotating/stretching/resizing of the original images

==Syntax==
===Convert an image===
>2jpeg s="c:\imagesfolder\image.bmp" -sf d="c:\out"

===Convert all the bitmap images in a folder===
>2jpeg s="c:\imagesfolder\*.bmp" -sf d="c:\out"

===Convert all the images in a folder===
>2jpeg s="c:\imagesfolder\*.*" -sf d="c:\out"

==External References==
*[http://batch.fcodersoft.com/2jpeg/ Download here]
*[[jpeg2ps]]
*[[2gif]]
[[Category:Technology]]
[[Category:Windows]]

SourceSafe

2006-10-10T18:43:56Z

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[http://en.wikipedia.org/wiki/Visual_SourceSafe Microsoft Source Safe] is the software used for [http://en.wikipedia.org/wiki/Source_control source control]. Other known version managers are [http://en.wikipedia.org/wiki/Concurrent_Versions_System cvs] or [http://en.wikipedia.org/wiki/Subversion_%28software%29 svn].
[http://www.sourcegear.com/sos/index.html SourceOffSite (sos)] is the software of choice when working from an outside network.

=== [http://www.sourcegear.com/sos/index.html SourceOffsite] ===

Here's a talk on using the [[sos]] [http://en.wikipedia.org/wiki/Command_line_interface CLI].
[[Category:Technology]]
[[Category:Windows]]

DODS

2006-10-10T18:37:22Z

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[http://en.wikipedia.org/wiki/Acronym Acronym] for '''D'''istributed '''O'''cean '''D'''ataset '''S'''ystem.

#REDIRECT [[OpenDAP]]
[[Category:Technology]]
[[Category:Linux]]

DAP

2006-10-10T18:37:10Z

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[[DAP]] is an acronym for '''D'''irect '''A'''ccess '''P'''rotocol.

#REDIRECT [[OpenDAP]]
[[Category:Technology]]
[[Category:Linux]]

Profiling

2006-10-10T18:31:34Z

192.168.20.110:

Is is possible to profile code compiled with the Intel Fortran compiler using gprof [http://www.cs.utah.edu/dept/old/texinfo/as/gprof_toc.html]. Intel Fortran's current release (9.1) requires Linux to generate profiling information.

== Quick dive ==
To generate profiling information follow these steps:
# ifort -p foo.F90 -o foo
# ./foo
# gprof foo
The first step will generate a executable with profiling information. At the end of the second step a file named gmon.out will be writen alongside the executable file; this file contains the profiling information generated during the program run. The third step screens the profile.

Note: the -p option must be issued both to compile and link the program.

== Profiling Mohid ==
To profile Mohid open the Makefiles used on [[*NIX platforms]]. Find variable CC in every makefile and replace "ifort" with "ifort -p". make clean, make and execute Mohid. At the end of the run a file named gmon.out will be created in the executable's folder. Explore gmon.out issuing the command gprof Mohid.

== Usefull links ==
NCSA [http://www.ncsa.uiuc.edu/UserInfo/Resources/Hardware/IBMp690/Doc/Timing_Profiling.html].

GNU prof [http://www.cs.utah.edu/dept/old/texinfo/as/gprof_toc.html].
[[Category:Technology]]
[[Category:Linux]]

Mpich2

2006-10-10T18:30:26Z

192.168.20.110:

MPICH2 allows to manage processes in cluster nix-based machines. It also allows the MPI being implemented in code.

==[[Dual_64]] quick start==
>export PATH=/home/fedora/Software/mpich2-1.0.3/bin:$PATH
[[Category:Technology]]
[[Category:Linux]]

Lynx

2006-10-10T18:28:55Z

192.168.20.110:

[http://en.wikipedia.org/wiki/Lynx_%28web_browser%29 Lynx] is a text-based web browser for [[*NIX_platforms|linux]]. Useful for command line web-browsing.

This command records the keystrokes used to download a file to the current directory.
>lynx -cmd_log:''/etc/lynx/lynx_getfile.log'' http://www.mohid.com/hydrogroup/presentations/file.ppt
This command exectuts the scripted keystrokes and downloads a file to the current directory.
>lynx -cmd_script:''/etc/lynx/lynx_getfile.log'' http://www.mohid.com/hydrogroup/presentations/file.ppt
[[Category:Technology]]
[[Category:Linux]]

Linux network restart

2006-10-10T18:28:40Z

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To initialize the network in linux without having to boot the machine:
>/etc/init.d/network start
>/etc/init.d/network stop
>/etc/init.d/network restart
[[Category:Technology]]
[[Category:Linux]]

Linux

2006-10-10T18:28:12Z

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#REDIRECT [[%2ANIX_platforms]]
[[Category:Technology]]
[[Category:Linux]]

Emerge

2006-10-10T18:27:32Z

192.168.20.110:

Emerge is a package manager typically found on Gentoo. Use it to install missing programs and required libraries.
==Searching for packages==
>emerge --search ''string''
==Installing a package==
>emerge ''package''
==Example==
>emerge --search rpm
Searching...
[ Results for search key : rpm ]
[ Applications found : 4 ]

* app-arch/deltarpm [ Masked ]
Latest version available: 3.3
Latest version installed: [ Not Installed ]
Size of downloaded files: 460 kB
Homepage: ftp://ftp.suse.com/pub/projects/deltarpm/
Description: tools to create and apply deltarpms
License: BSD

* app-arch/rpm
Latest version available: 4.2-r1
Latest version installed: 4.2-r1
Size of downloaded files: 28,541 kB
Homepage: http://www.rpm.org/
Description: Red Hat Package Management Utils
License: GPL-2 LGPL-2

* app-arch/rpm2targz
Latest version available: 9.0-r3
Latest version installed: 9.0-r3
Size of downloaded files: 7 kB
Homepage: http://www.slackware.com/config/packages.php
Description: Convert a .rpm file to a .tar.gz archive
License: as-is

* dev-perl/RPM
Latest version available: 0.40-r1
Latest version installed: [ Not Installed ]
Size of downloaded files: 53 kB
Homepage: http://search.cpan.org/author/RJRAY/Perl-RPM-0.40/
Description: RPM:: module for perl
License: || ( Artistic GPL-2 )

>emerge app-arch/rpm
[[Category:Technology]]
[[Category:Linux]]

Wind surface stress

2006-10-10T17:54:25Z

192.168.20.110:

Wind stress is calculated according to a quadratic friction law:

<math>\overrightarrow{{\tau_w}} = C_D \cdot \rho_a \cdot \overrightarrow{W}|\overrightarrow{W}|</math>

where <math>C_D</math> is a drag coefficient that is function of the wind speed, <math>\rho_{a}</math> is air density and <math>\overrightarrow{W}</math> is the wind speed at a height of 10 m over the sea surface.

[[Category:Science]]

Upwelling

2006-10-10T17:25:58Z

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Upwelling is quite well described [http://www.pfeg.noaa.gov/products/PFEL/modeled/indices/upwelling/NA/what_is_upwell.html here].

==Upwelling index ==
The upwelling index (''UI'') is defined as the ''Ekman Transport per 100 m of coastline'' induced by wind parallel to the coast. In the Western Iberian coast. This corresponds to the zonal component of the wind.

The [[#The Ekman transport|''volume Ekman transport'']] is defined in ''Kundu'' as the momentum of a steady-state horizontally homogeneous viscid geophysical flow integrated over depth. Thus, assuming a steady state constant zonal wind stress <math>\tau</math>

<math>UI=-100\,\frac{\tau}{\rho\,f}</math> m3/s/100m.

===Wind stress===
To calculate the wind stress <math>\tau</math> from the wind velocity modulus <math>U_{10}</math> (air speed at 10 m height from the free surface) ''Ekman'' used the bulk formula:

<math>\tau=\rho_{air}C_D\,U_{10}^2</math>

<math>\rho_{air}=1.25</math> ''kg/m3'' is an usual value for the air density.

<math>C_D</math> is an air drag coefficient. It is mainly dependent from surface rugosity length ''z0'' and from the [[Richardson number]]. However a large case of linear parameterizations is available throughout the litterature, with no well defined standard:

<math>C_D = a + b\,U_{10}</math>

*''Large & Pond 1981'' use ''CD = .44 + .63 U10'',
*''Smith & Banke 1975'' use ''CD = .63 + .66U10''.

==Viscid, horizontally homogeneous, steady-state, geophysical fluid equations==
The flow equations of motion are given in ''Kundu'' by

<math>-fv=\nu \frac{d^2u}{d z^2},</math>

<math>fu=\nu \frac{d^2v}{d z^2}.</math>

==The Ekman spiral==
''Kundu'' shows that when acted by a constant wind stress <math>\tau</math> along the ''x''-direction, the solution to the above equations yield

<math>u=\frac{\tau/\rho}{\sqrt{f\nu}}e^{z/\delta}\cos\left(-\frac{z}{8}+\frac{\pi}{4}\right),</math>

<math>v=-\frac{\tau/\rho}{\sqrt{f\nu}}e^{z/\delta}\sin\left(-\frac{z}{8}+\frac{\pi}{4}\right),</math>

where <math>\delta\equiv\sqrt{\frac{2 \nu}{f}}.</math>

The velocity vector rotates clockwise (looking down) with dept. Its magnitude decays exponentially as well with decay constant <math>\delta</math>. This spiral shaped flow is called the ''Ekman spiral''.
In the works of Ekman, Ekman defined a thickness of decay of the spiraled flow based on the flow geometry. This thickness later defined the ''Ekman layer'' and is usually around 50 m for the open ocean(''Stewart''). ''Kundu'' however defines the thickness of the Ekman layer simply by its decay constant <math>\delta</math>.

==The Ekman transport==
When acted by a constant wind stress <math>\tau</math> along the ''x''-direction, the volume transport in the Ekman layer is given by

<math>\int_{-\infty}^{0}u\,dz=0</math>,

<math>\int_{-\infty}^{0}v\,dz=-\frac{\tau}{\rho\,f}</math>.

Thus the ''net transport is to the right of the wind stress in the northern hemisphere'' and is independent of viscosity. This is due because near the surface <math>\rho \nu \frac{du}{dz}=\tau,\quad z=0</math>.
Over statistical flow averages, the ''Ekman transport'' calculation fits very well with experimental data and, thus, is considered a reliable calculation.

==References==
#''Kundu''
#''Stewart''
#''Pietrzak2002''
#''Large & Pond 1981''
#''Smith & Banke 1975''

[[Category:Science]]

MohidWiki - User contributions [en]

Cvs

Categories

Index

Hyperslab

Fetch

2jpeg

SourceSafe

DODS

DAP

Profiling

Mpich2

Lynx

Linux network restart

Linux

Emerge

Wind surface stress

Upwelling