; IDL Version 7.1.1 (linux x86_64 m64)
; Journal File for mats@sally
; Working directory: /home/mats/idl/develop/matrixalgebra
; Date: Thu Apr  5 16:19:19 2012
 
;Check array dimensions with size( ,/dim):
;A:           3
;B:           1           3
; 
; 
;================================  With the # operator:
; 
;------ |A| (op:#) [3x1] ------
;    0
;    1
;    2
;------------------------------
; 
;------ |B| (op:#) [1x3] ------
;    1     3     5
;------------------------------
; 
;------ |A # B| (op:#) [3x3] ------
;    0     0     0
;    1     3     5
;    2     6    10
;----------------------------------
; 
;OK, a 3-element column vector times a 3-element row vector is a 3x3 matrix.
; 
;------ |B # A| (op:#) [1x1] ------
;   13
;----------------------------------
; 
;OK, a row vector times a column vector is a 1x1 matrix.
; 
; 
;================================  With the ## operator:
; 
;------ |A| (op:##) [1x3] ------
;    0     1     2
;-------------------------------
; 
;------ |B| (op:##) [3x1] ------
;    1
;    3
;    5
;-------------------------------
; 
;------ |A ## B| (op:##) [1x1] ------
;   13
;------------------------------------
; 
;OK, a row vector times a column vector is a 1x1 matrix.
; 
;------ |B ## A| (op:##) [3x3] ------
;    0     1     2
;    0     3     6
;    0     5    10
;------------------------------------
; 
;OK, a 3-element column vector times a 3-element row vector is a 3x3 matrix.