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Glas :Re: [glas] return type of operator[](size_type) for sparse vectors? |
From: Russell Smiley (smiley_at_[hidden])
Date: 2006-04-26 15:11:21
I think I prefer option 3 (proxy that modifies a structural zero if
necessary). Presumably there is some penalty for this more sophisticated
behaviour.
If "proxy_type operator[]" is not provided how would structural zeroes
normally be modified?
Russell.
> -----Original Message-----
> Subject: [glas] return type of operator[](size_type) for
> sparse vectors?
>
>
> Given a sparse vector v of size 10, what would v[0] return? Should it
> return a reference to the element at position 0 in the sparse vector.
> What if that element is a structural-zero? It clearly is not as
> straightforward as with dense vectors.
>
> The options AFAICT are:
> 1) provide no 'operator[](size_type)' to avoid confusion
>
> 2) return the value at the corresponding position or if the position
> corresponds to a structural-zero return zero. Thus in that case
> operator[] will not affect/change the structure and
> operator[] will not
> allow to change the value at the corresponding position.
>
> 3) return a proxy. If the proxy is being assigned to, the
> structure will
> be changed in case the position corresponded with a structural-zero.
>