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40 lines
1.5 KiB
ReStructuredText
40 lines
1.5 KiB
ReStructuredText
The central concept : HasImmutableArrayInterface
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The central concept used by the library (both in the colloquial and in the technical acceptance of the word)
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is the notion of **Immutable Array Interface**.
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This is just a formal definition of what has an object has to implement ("which concept it has to model")
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to look like an array.
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Basically, the answer is simple, an array is a (discrete) map between a domain of indices into an algebra
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(typically R, ou C). Therefore it has to defined :
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* a domain of indices, which can be enumerated, e.g. cartesian products of integer ranges.
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* an evaluation method [] so that a[ I ] has a `value_type` type for any index I in the domain.
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The precise concept if defined at :ref:`HasImmutableArrayInterface` concept.
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Examples :
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* a matrix has a domain of range(0,n1) x range(0,n2).
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* a general array has a domain of dimension rank and values in R, C, other arrays...
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* a triangular matrix has a more complex domain...
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* any algebraic expression of arrays, matrices are like this (and those one are certainly NOT mutable objects !).
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* What is then a (partial) view/slice of an array ?
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Simply another map on the same data.
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* Do you want to see a 4 indices arrays as a matrix of double indices ?
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Simply change the map...
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* Why is this concept useful ?
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Because if you program another object of your own, which models it,
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it is guaranteed to interact properly with arrays....
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