Bug #1517: Matrix[] Performs No Argument Validation, Confusing Some of Its Instance Methods

• Status: Closed
• Assignee: keiju (Keiju Ishitsuka)

[runpaint (Run Paint Run Run)]

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The Matrix[] constructor accepts anything as argument. This can cause problems for its instance methods. For example, consider a Fixnum:

 >> m = Matrix[1]
 => Matrix[1]

This works as you'd expect. But then:

 >> m.row(0)
 TypeError: can't dup Fixnum
from /usr/lib/ruby/1.9.0/matrix.rb:1132:in `dup'
from /usr/lib/ruby/1.9.0/matrix.rb:1132:in `init_elements'
from /usr/lib/ruby/1.9.0/matrix.rb:1124:in `initialize'
from /usr/lib/ruby/1.9.0/matrix.rb:1117:in `new'
from /usr/lib/ruby/1.9.0/matrix.rb:1117:in `elements'
from /usr/lib/ruby/1.9.0/matrix.rb:303:in `row'
from (irb):20
from /usr/bin/irb1.9:12:in `<main>'

Or:

 >> m.column_size
 => 4

Which leads to:

 >> m.column_vectors
 => [Vector[1], Vector[0], Vector[0], Vector[0]]

If such arguments are accepted, Matrix should coerce them into a matrix. Presumably, the easiest approach would be to have Matrix[1] == Matrix[[1]]. Otherwise, Matrix[] should raise an ArgumentError if it doesn't receive an Array. Ideally, you should only be able to create matrices of Arrays of Numeric-like objects. The current behaviour is non-intuitive, and invites bugs.
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[marcandre (Marc-Andre Lafortune)]

• Category set to lib
• Assignee set to keiju (Keiju Ishitsuka)

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[keiju (Keiju Ishitsuka)]

• Status changed from Open to Closed

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