Mailing-List: contact user-help@commons.apache.org; run by ezmlm
Precedence: bulk
Reply-To: "Commons Users List" <user@commons.apache.org>
Received-SPF: pass (athena.apache.org: domain of cnguyen7@iit.edu designates
 216.47.143.127 as permitted sender)
MIME-version: 1.0
Content-type: text/plain; charset=iso-8859-1
From: "Cuong P. Nguyen" <cnguyen7@iit.edu>
To: 'Commons Users List' <user@commons.apache.org>
References: <010401cb6d52$b75d1df0$261759d0$@edu> <4CB9EE01.70106@free.fr>
 <011301cb6d61$4937a570$dba6f050$@edu> <4CB9F623.6050802@free.fr>
In-reply-to: <4CB9F623.6050802@free.fr>
Subject: [math] Re: complex matrix operation
Date: Sat, 16 Oct 2010 15:47:01 -0500
Message-id: <011401cb6d73$485e0920$d91a1b60$@edu>
Content-transfer-encoding: quoted-printable
Thread-index: ActtZN148D9ye+c3TwavcWGQeXipnAADUQKQ
Content-language: en-us

Hi Luc and friends,=20

I have a question more related to java matrix storage. If I have a
3-dimentional m matrix say 2 by 2 by 2, I want to access the matrix
efficiently so I would like to know the order in which the data is =
stored in
the memory. I am not sure if it is stored consecutively this way in the
memory register:
m(1,1,1), m(1,1,2), m(1,2,1), m(1,2,2), m(2,1,1), m(2,1,2), m(2,2,1),
m(2,2,2)

I also wonder if the package could store sparse vectors, matrices and
perform basic operations on them?

Thanks,
Cuong

-----Original Message-----
From: Luc Maisonobe [mailto:Luc.Maisonobe@free.fr]=20
Sent: Saturday, October 16, 2010 2:00 PM
To: Commons Users List
Subject: Re: [math] Re: complex matrix operation

Le 16/10/2010 20:38, Cuong P. Nguyen a =E9crit :
> Hi Luc and friends,=20
>=20
> Thanks a lot for the quick response
>=20
> Could you give me any simple code example of Complex-type =
vector-matrix
> multiplication or matrix-matrix multiplication ?

Here is a matrix vector multiplication:

// create a 2x2 complex matrix
Complex[][] matrixData =3D new Complex[][] {
    { new Complex(1.0,  0.0), new Complex( 0.0, 1.0) },
    { new Complex(0.0, -1.0), new Complex(-1.0, 0.0) }
};
FieldMatrix<Complex> m =3D new =
Array2DRowFieldMatrix<Complex>(matrixData);

// create a vector
Complex[] vectorData =3D new Complex[] {
    new Complex(1.0, 2.0),
    new Complex(3.0, 4.0),
};
FieldVector<Complex> u =3D new ArrayFieldVector<Complex>(vectorData);

// perform matrix-vector multiplication
FieldVector<Complex> v =3D m.operate(u);

// print the initial vector
for (int i =3D 0; i < u.getDimension(); ++i) {
    System.out.println(ComplexFormat.formatComplex(u.getEntry(i)));
}

System.out.println();

// print the result
for (int i =3D 0; i < v.getDimension(); ++i) {
    System.out.println(ComplexFormat.formatComplex(v.getEntry(i)));
}


Luc

>=20
> I am a new java beginner as well as new to Commons Math community.
>=20
> Thanks,
>=20
> Cuong
>=20
> -----Original Message-----
> From: Luc Maisonobe [mailto:Luc.Maisonobe@free.fr]=20
> Sent: Saturday, October 16, 2010 1:25 PM
> To: Commons Users List
> Subject: [math] Re: complex matrix operation
>=20
> Le 16/10/2010 18:53, Cuong P. Nguyen a =E9crit :
>> Hi,
>=20
> Hi Cuong,
>=20
> First, please use a [math] marker on the subject line when posting to
> this list for the commons-math component. The list is shared among
> several commons components and these markers help filtering.
>=20
>> can I use the package for basic complex-number matrix operations
>> (addition, subtraction, multiplication) ?
>=20
> You can use the linear algebra packe from commons-math with complex
> matrices. The appropriate interface is FieldMatrix<Complex> which has
> two implementations: Array2DRowFieldMatrix<Complex> and
> BlockFieldMatrix<Complex>. The former should be preferred for small
> sizes and the later for large sizes. You can also use complex vectors
> and LU decomposition with these matrices.
>=20
> Luc
>=20
>>
>> Thanks
>>
>> Cuong
>>
>>
>=20
>=20
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
> For additional commands, e-mail: user-help@commons.apache.org
>=20
>=20
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
> For additional commands, e-mail: user-help@commons.apache.org
>=20


---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
For additional commands, e-mail: user-help@commons.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
For additional commands, e-mail: user-help@commons.apache.org