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

[Fernando Perez]

Robert Kern wrote:
> Fernando Perez wrote:
> 
> 
>>There is one important reason to want to have pure non-conjugating 
>>functions: performance.  If you are writing code which is using purely 
>>real arrays, and dot/inner are at the center of your critical path, you 
>>do NOT want constant type checks or no-op conjugations to be taking 
>>place.  Now, I am not arguing that the current choice of names was a 
>>good one, but there is a very valid reason for having an explicitely, 
>>purely real set of functions.
> 
> 
> I don't think that there would be a performance hit by making 
> dot/innerproduct do a conjugation. dot has to dispatch on the typecodes 
> in any case. It should just be a matter of changing a couple signs in 
> the complex case (or calling the appropriate BLAS functions for dotblas).

Well, if it could really be done with no measurable performance hit at all, 
then I'd be all for a 'mathematically correct' inner/dot.  But I'd like to see 
that shown by measurement, across a large set of sizes.  Maybe you're right, 
I'm just being a bit picky :)

Cheers,

f