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From "Edward J. Yoon (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HAMA-13) Scalar and Matrix Multiplication
Date Wed, 30 Jul 2008 06:17:31 GMT
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[ https://issues.apache.org/jira/browse/HAMA-13?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Edward J. Yoon updated HAMA-13:
-------------------------------

Description:
There are two types of multiplication for matrices: scalar multiplication and matrix multiplication.
Scalar multiplication is easy. You just take a number (called a "scalar") and multiply it
on every entry in the matrix. For example,

For the following matrix A, find 2A :

2A = 2- {[a, b], [c, d]} = {[2- a, 2- b], [2- c, - d]}

however, matrix multiplication is quite another story. We need to multiply the ROWS of A by
the COLUMNS of B. By this I mean that I first take the first row of A and the first column
of B, and we multiply the first entries, then the second entries, and then the third entries,
and then we add the three products. The sum is one entry in the product matrix AB.

reference : http://carbon.cudenver.edu/csprojects/CSC5809S01/Simd/parmult.html

was:There are two types of multiplication for matrices: scalar multiplication and matrix
multiplication. Scalar multiplication is easy. You just take a number (called a "scalar")
and multiply it on every entry in the matrix. however, matrix multiplication is quite another
story.

> Scalar and Matrix Multiplication
> ---------------------------------
>
>                 Key: HAMA-13
>                 URL: https://issues.apache.org/jira/browse/HAMA-13
>             Project: Hama
>          Issue Type: Improvement
>          Components: algorithm
>            Reporter: Edward J. Yoon
>
> There are two types of multiplication for matrices: scalar multiplication and matrix
multiplication. Scalar multiplication is easy. You just take a number (called a "scalar")
and multiply it on every entry in the matrix. For example,
> For the following matrix A, find 2A :
> 2A = 2- {[a, b], [c, d]} = {[2- a, 2- b], [2- c, - d]}
> however, matrix multiplication is quite another story. We need to multiply the ROWS of
A by the COLUMNS of B. By this I mean that I first take the first row of A and the first column
of B, and we multiply the first entries, then the second entries, and then the third entries,
and then we add the three products. The sum is one entry in the product matrix AB.
> reference : http://carbon.cudenver.edu/csprojects/CSC5809S01/Simd/parmult.html

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