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Feature #14116

Add Matrix #exponentiate method as Matlab's exp

Added by greggzst (Grzegorz Jakubiak) almost 2 years ago. Updated almost 2 years ago.

Status:
Feedback
Priority:
Normal
Target version:
-
[ruby-core:83827]

Description

Add exponentiate method which results in returning a new matrix with each element being an exponent of the number e.
Here is PR for that: https://github.com/ruby/ruby/pull/1762

History

#1

Updated by greggzst (Grzegorz Jakubiak) almost 2 years ago

  • Description updated (diff)
#2

Updated by greggzst (Grzegorz Jakubiak) almost 2 years ago

  • Subject changed from Add Matrix #exponentiate method to Add Matrix #exponentiate method as Matlab's exp

Updated by marcandre (Marc-Andre Lafortune) almost 2 years ago

  • Assignee set to marcandre (Marc-Andre Lafortune)
  • Status changed from Open to Feedback

Thanks for the PR.

The name is not acceptable, as the exponential of a matrix is something different (expm in Matlab): https://en.wikipedia.org/wiki/Matrix_exponential

I wish I was more familiar with machine learning to know how frequent calculating this is. If it is, there should be a name for this, no?

The fact that map{|e| Math.exp(e)} is quite simple to do makes me even more hesitant to add that method too.

Updated by MSP-Greg (Greg L) almost 2 years ago

marcandre (Marc-Andre Lafortune) wrote:

Thanks for the PR.

The name is not acceptable, as the exponential of a matrix is something different

I agree. Not quite a single line method. Maybe something like entrywise_exp or entrywise_exponential like in 60860. But as you mentioned, 'is quite simple'...

Updated by shevegen (Robert A. Heiler) almost 2 years ago

Once again it is back to the oldest problem in computer technology - giving things a proper name. :-)

Updated by greggzst (Grzegorz Jakubiak) almost 2 years ago

marcandre (Marc-Andre Lafortune) wrote:

Thanks for the PR.

The name is not acceptable, as the exponential of a matrix is something different (expm in Matlab): https://en.wikipedia.org/wiki/Matrix_exponential

I wish I was more familiar with machine learning to know how frequent calculating this is. If it is, there should be a name for this, no?

The fact that map{|e| Math.exp(e)} is quite simple to do makes me even more hesitant to add that method too.

I changed the name to entrywise_exp as suggested. True about the simplicity but it would be a good shorthand taking into consideration fact that it is used in many cases e.g. multivariate normal distribution.

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