[SciPy-user] complex vector scalar product: wrong implementation

[Robert Kern]

Lance Boyle wrote:
> 
> On Jan 11, 2005, at 2:56 AM, Robert Kern wrote:
> 
>> Not everyone using Numeric with dot() and complex numbers is doing 
>> linear algebra.
> 
> 
> Anyone invoking dot() expects a dot product, PERIOD. Unless they have 
> adapted to the idiosyncrasy of Python Numeric in order to get their work 
> done.
 >
> I'm very casual reader of this list so I might have missed something. 
> However, the original poster demonstrates a design flaw and it should be 
> fixed. There is no math text in existence that promotes a dot product 
> that is not an inner product. Sure, names are arbitrary, but bad names 
> are bad design. In "sarcasm" mode, I might say, why not name the sine 
> function cos() and the cosine function sin().

You won't get any argument from me that the name is bad (well, actually, 
the error is duplicated: both "dot" and "innerproduct" are bad names). 
If I had been around during Numeric's formative years, I would have 
argued strongly for having dot/innerproduct do the conjugation. I would 
also have argued that they should implement a proper tensor inner 
product for N-D arrays N>2 (dot(A,B) contracting on the last axis of A 
and the first axis of B rather than the current implementation).

I don't agree that we should change either of these behaviours at this 
time. The amount of code that depends on these well-documented 
behaviours is too great.

I have no problem with putting functions into scipy.linalg that do the 
right things for linear algebra.

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter