[ruby-core:75394] [Ruby trunk Bug#12356] Vector covector incorrect multiplication with another vector.

From: rafael.soares81@...
Date: 2016-05-06 23:51:54 UTC
List: ruby-core #75394
Issue #12356 has been reported by Rafael Silva.

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Bug #12356: Vector covector incorrect multiplication with another vector.
https://bugs.ruby-lang.org/issues/12356

* Author: Rafael Silva
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.4p230 (2015-12-16 revision 53155) [x86_64-linux]
* Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN
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Version 2.2.4

v1	=	Vector[2,3,4]
v2	=	Vector[4,5,6]
v1.covector.row_size      #1
v1.covector.column_size   #3
v2.covector.row_size      #1
v2.covector.column_size   #3

Vector does not have distinction between row and column, there's no column vector notion in the language.

v1 * v2.covector #Matrix[[8,10,12],[12,15,18],[16,20,24]]
# Should be illegal. But works like if v2.covector is transposed / column vector which it's clearly not.

v1.covector * v2.covector #ExceptionForMatrix::ErrDimensionMismatch: Matrix dimension mismatch
# Expected

v1 * v2 #ExceptionForMatrix::ErrOperationNotDefined: Operation(*) can't be defined: Vector op Vector
# No comments, see my observation below.

v1.covector * v2 #Vector[47]
#Again covector treated like transposed / column vector.

Personal observation: Terrible choice to represent Vector like an Array, Vector should be a shortcut to Matrix.



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