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