Free openfoam compressible example software for linux

GNUstep examples is a collection of programs that are meant to show programmers how to use GNUstep.
GNUstep examples includes a calculator, a currency converter, finger, fractal, puzzle, hostaddress, and ink (a simple editor).
Enhancements:
- Minor feature enhancements

DTLS Client/Server Example contains a simple DTLS client and DTLS server to show how to send UDP data over an encrypted channel using OpenSSL DTLSv1 support.

LIST OF FILES:

Directory: common - Contains callback functions and error reporting functions common to client and server

sslmgr.h
sslmgr.c

Directory: dtls_server

dtls_server.c - DTLS server part

Directory: dtls_client

dtls_client.c - DTLS client part

Java::Import::Examples is an example of how to use Java::Import to call into Java classes.

Making RMI calls from Perl

One nice thing about Java is the extremely straight forward manner in which it allows you to make calls to remote objects residing on distant servers. Many people use this ability as a point of integration between their system and a posible third party or legacy system. Unfortunatly, for the most part the ability to make calls to these remote objects is something that only other Java applications can do without making a big fuss about it. However, we can now do this from Perl.

Assume that I have a RMI server from which I can get data from in the form of simple Java Beans. One method of doing this is to use the GCJ::Cni library and natively compile and wrap a set of Java Classes which can then be used from my Perl script. However, there is an easier way.

Lets begin by descriping the Java interfaces that well be working with. We first have the Remote Interface that we will be interacting with:

import java.rmi.*;
public interface RemoteInterface extends Remote {
public SomeBean getMessage(String seedMessage) throws RemoteException;
}
And we also have the bean we will be asking for:
import java.io.*;
public class SomeBean implements Serializable {
private String value;
public SomeBean() {}
public void setValue ( String _value ) { ... }
public String getValue ( ) { ... }
}
As far as any Perl client program is concerned this is all we need to know about.
Now all there is left to do is write a client:
use Java::Import qw(
java.rmi.Naming
);

my $remote_interface = java::rmi::Naming->lookup(jstring("//localhost/Home"));
my $bean = $remote_interface->getMessage(jstring("Hi there"));
print $bean->getValue(), "n";

Thats all there is. Notice that all we had to tell Java::Import about was java.rmi.Naming, this is because it was the only class we used by name in our Perl code, every other Java class (the objects held by $bean and $remote_interface) was returned by some other method call originating from java.rmi.Naming.

In order to run this example we have to make sure everything is in its place. We start by compiling the client code. Assuming that we have been given a Stub class file (RemoteObject_Stub.class) we can do the following:

gcj -C SomeBean.java RemoteInterface.java
fastjar -cvf client.jar SomeBean.class RemoteInterface.class RemoteObject_Stub.class

Making sure our server is reachable we can then run the client code:

CLASSPATH=client.jar perl client.pl

Thats it, you should then see the message returned by your server.

GCJ::Cni::Examples is a Perl module with examples of how to use GCJs CNI interface to write Perl Modules in Java.

EXAMPLES

Writing Treaded modules in Java

One benefit of using GCJ is that it takes advantage of POSIX threading. This is nice since Perls threading model is, shall we say, less than ideal. Now, you could theoretically write a module in C or C++ and and use the standard POSIX library to do your threaded work for you, however, why not take advantage of the nice Threading interface that Java provides to you by default. This may also come in handy if you have a massively threaded Java library that youd like to call from Perl.

For this example assume that I want to do matrix multiplication, albeit in a very crazy manner. Therefore, I will write a Java class, Matrix, and a method, multiply, which will take another matrix to perform the operation between. Heres the crazy part, for each cell in the resulting matrix I will spawn a new thread, as an internal class, and give it a row and a column from which they will derive the result. I know this is a little wierd but the point is that Ill be spawning a lot of new threads. To multiply two 10x10 matrices we will have to spawn 100 threads (one thread per cell in the resulting 10x10 matrix). Imagine doing this in Perl, then imagine doing it in Java; natively compiled Java. Much faster and a lot less headaches.

The Java Interface/pseudocode is as follows:

public class Matrix {
public Matrix ( int numRows, int numCols ) {
...Constructor stuff...
}

public void set ( int row, int col, int val ) {
...set an element...
}

public int get ( int row, int col ) {
...get an element...
}

public Matrix multiply ( Matrix times ) {
...set it up...
for ( int i = 0; i < rows; i++ ) {
for ( int j = 0; j < times.getCols(); j++ ) {
//GO NUTS!!!!
ArrayMultiplier multiplier = new ArrayMultiplier(this, times, result, i, j);
multiplier.start();
...etc...
}
}
...wait for the threads to exit and return the new matrix...
}

public int getRows ( ) {
...get number of rows...
}

public int getCols ( ) {
...get number of columns...
}

public void print ( ) {
...print the matrix to stdout...
}

private class ArrayMultiplier extends Thread {
public ArrayMultiplier ( Matrix a, Matrix b, Matrix result, int row, int col ) {
...Construct this bad boy...
}

public void run ( ) {
int sum = 0;
for ( int i = 0; i < a.getCols(); i++ ) {
sum += (a.get(row, i) * b.get(i, col));
}
result.set(row, col, sum);
}

}
}
Now, we want to call this class from Perl. My perferred manner is through SWIG so thats what were going to use. However, you do not need to use SWIG, you can use whatever method you prefer when wrapping C++ classes. We begin by creating a C++ header file from our above class. This is done by using GCJs gcjh utility. First we need to class compile Matrix.java

gcj -C Matrix.java

Then we go ahead and create the header file:

gcjh Matrix

Easy enough. We can then extract the interface we want to have available in Perl from the generated header file and from it create a i file to be used as input to SWIG. I usually start by copying my header file to the same named file but with an i extension instead. I then remove all of the grimy C++ gruff, private methods and variables, slap a module directive on it and call it done. It wont always be this easy though. When youre done an interface file for the above class should look something like this:

%module Matrix;

typedef int jint;

class Matrix
{
public:
Matrix (jint, jint);
virtual void set (jint, jint, jint);
virtual jint get (jint, jint);
virtual ::Matrix *multiply (::Matrix *);
virtual jint getRows ();
virtual jint getCols ();
virtual void print ();
};
We then put SWIG to work and generate our C++ wrapper for Perl:

swig -perl -c++ Matrix.i

After the above command we now will see two new files in our current directory, Matrix.pm and Matrix_wrap.cxx; these correspond the module directive we gave in Matrix.i.

At this point all we have left to do is compile, and use.

gcj -c Matrix.java
gcc -c -I -include Matrix.h Matrix_wrap.cxx
gcc -shared -lgcj -lstdc++ Matrix.o Matrix_wrap.o -oMatrix.so

A simple Perl file using this module might look something like:

sub populate_matrix {
my $matrix = shift;
for ( my $i = 0; $i < $matrix->getRows(); $i++ ) {
for ( my $j = 0; $j < $matrix->getCols(); $j++ ) {
$matrix->set($i, $j, $i * $j);
}
}
}

use GCJ::Cni;
use Matrix;

GCJ::Cni::JvCreateJavaVM(undef);
GCJ::Cni::JvAttachCurrentThread(undef, undef);

my $matrix = new Matrix::Matrix(10, 10);
populate_matrix($matrix);
my $matrix2 = new Matrix::Matrix(10, 10);
populate_matrix($matrix2);
$matrix3 = $matrix->multiply($matrix2);
$matrix3->print();

GCJ::Cni::JvDetachCurrentThread();

Ill leave it up to the reader to write a Perl module that does the same thing, that is, spawns 100 threads. In my own personal fiddling I found that just spawning that many threads (never mind doing any kind of work) was over 3 time slower in Perl. In this situation we at least get to use our favorite language, Perl, and offload some of the heavy hitting to a language more suited for it.

Where this really comes in handy is when you have an existing multi-threaded Java library that you would like to expose to Perl. You could theoretically natively compile various components of your library and then generate Perl bindings to access it. In this way, you get a little extra speed and efficiency as well as code reuse and binding.

python-gastables includes Python modules for compressible gas flow calculations.

The project includes Python modules for isentropic relations, normal shock relations, oblique shock relations, Fanno flow, isothermal flow, Rayleigh flow, and Prandtl Meyer functions.

Set up iptables NAT rules is an example IPTables 1.2.1 script for a multi-homed firewall.

Please feel free to send me any comments or suggestions.

Current versions and documentation are available at http://www.sentry.net/~obsid/IPTables/rc.scripts.dir/current/

Sample:

## Variables ##
IPTABLES="/usr/local/sbin/iptables" ## Default IPTables >= v. 1.2.0
#IPTABLES="/usr/local/bin/iptables" ## Default IPTables<<less