[Numpy-discussion] improvement request to np.dot(a, b) - extended precision summation

[David Henderson]

Hello all,

I'd like accumulate the summation in extended precision, "double"   
sum for float  inputs, "long double" sum for "double" inputs.

A way of doing this is to add an optional third argument to dot - to  
specify the summation type.

I've looked into the code, and the source file multiarraymodule.c has  
a routine:
        new_array_for_sum(PyArrayObject *ap1, PyArrayObject *ap2,

If the implementation is to pass a third argument to dot that  
specifies the resultant type, this routine would be modified to add  
that third argument or type in its priority selection logic.

I've not written any code yet, and I'm not fussy as to how it gets  
done. Is there another way to do this that I'm missing?

Thanks in advance,

David