[Scilab-users] undocumented behavior of sum(), prod() and type()

[Federico Miyara]

Thanks, Samuel.

This certainly clarifies how [] behaves. But is there a rationale for 
sum([])==0 and yet cumsum([])==[]?

By the way, it would be useful to include cumsum and cumprod among the 
examples, or at least ensure the respective help pages include that 
information.

Regards,

Federico

On 09/02/2020 00:40, Samuel Gougeon wrote:
> Hello federico,
>
> The empty page is improved in 6.1.0. Please have a look to
> http://bugzilla.scilab.org/15431
> http://bugzilla.scilab.org/attachment.cgi?id=4929
>
> Thanks
> Samuel
>
> Le 09/02/2020 à 04:27, Federico Miyara a écrit :
>>
>> Dear all,
>>
>> I note that sum([]) yields 0 instead of []. This is somewhat 
>> contradictory with the documented behavior that [] + n yields [] 
>> regardless of the type of n
>>
>> I allso find that prod([]) yields 1. This is even stranger. The 
>> common feature is that both are the respective neutral element of the 
>> operations.
>>
>> Interestingly, cumsum and cumprod applied to [] yield the expected 
>> result, []
>>
>> Besides, type([]) is 1 (constant). Somehow it is asuming an empty 
>> matrix is by default a container for constants, even in csses such as 
>> the following:
>>
>> a = %s
>> b = a(1:$-1)
>>
>> where b is an empty sub-vector of a polynomial vector.
>>
>> None of these behaviors seem to be documented. If intentional, they 
>> should be documented.
>>
>> Regards,
>>
>> Federico Miyara
>>
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