Re: [Bug-apl] inner product behaviour?

[Juergen Sauermann]

Hi,

the standard says:

If the last-item in the shape-list of A1 is not the same as the first-item in the shape-list
of B1, signal length-error.

Scalar A or B are turned into vectors, but vectors are not turned into matrices.
In your example the last dimension of A was 2 and the first dimension of B was 3.

/// Jürgen

On 08/15/2015 08:22 PM, address@hidden wrote:

Hi Bug APL,

Does the inner product coerce a vector to a matrix only when (⍴right arg vector)≤ left arg number of columns (when it is a matrix)?

      rotatemat←{2 2 ⍴ (2○⍵)(-1○⍵)(1○⍵)(2○⍵)}

      rm←rotatmat 3

VALUE ERROR

      rm←rotatmat 3

         ^

      rm←rotatemat 3

      rm

¯0.9899924966 ¯0.1411200081

 0.1411200081 ¯0.9899924966

      rm+.×(1 1) 

¯1.131112505 ¯0.8488724885

      rm+.×(1 1)(2 2)

 ¯1.272232513 ¯1.272232513  ¯1.838864985 ¯1.838864985 

      rm+.×(1 1)(2 2)(3 3)

LENGTH ERROR

      rm+.×(1 1) (2 2) (3 3)

      ^   ^

      rm+.×1 3⍴(1 1)(2 2)(3 3)

 ¯1.131112505 ¯1.131112505    ¯2.262225009 ¯2.262225009  ¯3.393337514 

      ¯3.393337514 

 ¯0.8488724885 ¯0.8488724885  ¯1.697744977 ¯1.697744977  ¯2.546617466 

      ¯2.546617466