[HAMA-174] Compute the transpose of a matrix

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: math
• Assignee: Edward J. Yoon
• Reporter: Edward J. Yoon
• Created: 16/Mar/09 02:19
• Updated: 08/Jun/11 09:32
• Resolved: 21/Apr/09 04:14

Description

The transpose of a matrix is another matrix in which the rows and columns have been reversed. The matrix must be square for this work.

a11 a12 a13		a11 a21 a31
a21 a22 a23	=>	a12 a22 a32
a31 a32 a33		a13 a23 a33

• A map task receives a row n as a key, and vector of each row as its value
• emit (Reversed index, the entry with the given index)

ex) row = 1,

{ 1: a11, 2: a12, 3: a13 }

a11, a11
a21, a12
a31, a13
...

• Reduce task sets the reversed values

Issue Links

• relates to: HAMA-176 Implementation of singular value decomposition