Multidimensional arrays for D

[Zardoz]

On Tue, 25 Oct 2011 14:52:04 +0300, Denis Shelomovskij wrote:

Looks interesting. This summer I did a small lib around vectors and matrices, at same time that I was 
learning D. Perhaps you can borrow some idea or not. It's focused for using it with OpenGL so they are 
limited to squared matrices of 2 to 4 dimension and column major ordered  : 
https://github.com/Zardoz89/zmath

> What does D already have: build-in rectangular static arrays, dynamic
> arrays of arrays, std.range.frontTransversal, std.range.transversal.
> 
> Some time ago I was told that "FORTRAN is good for its arrays" and heard
> me saying "it is easy to implement in C++ or D, but in D it will have
> more convenient syntax". But than I have understood that I
> underestimated the problem and it isn't easy to implement in D and looks
> much more harder to implement in C++. In spite of this I decided to
> implement it in D. So, my implementation is ready for test/use but still
> has some TODO-s because it is just a straightforward implementation of
> basic multidimensional array operations with no optimisations. And I
> think it is valuable enough to be added in Phobos in future (tell me if
> it isn't).
> 
> Documentation and sources:
> http://deoma-cmd.ru/d/docs/src/my/rarray.html
> 
> Sources will be at GitHub as soon as I am asked for it.
> 
> I have some questions about my array: * Should such array be a part of
> Phobos or Druntime? * Now my array has CT dimensions and RT lengths,
> should there be a version with RT dimensions (or maybe it is the only
> needed version)? * Some (or most) of element names should be changed
> (like RectangularArray, because is isn't a rectangular array in the
> general case). So if one knows better names, tell me please (at least
> RectangularArray -> MultidimensionalArray, rectArray -> multiArray?). *
> Have I misused some terminology (top dimension etc.)? * What `Throwable`
> types should be thrown and when? Currently I use `AssertError` for my
> own mistakes and user incorrect ranges using and `Exception` for user
> incorrect array using, all are in debug mode only. And I don't
> understand Druntime exceptions: it uses `Exception` for "lengths don't
> match for array copy" and `core.exception.RangeError` if array index is
> out of bounds and calls it "Range violation" (all are in debug mode
> only). It looks inconsistent. * For `int a = b / c, d = b % c;` will
> compiler optimize it or should I add there an inline assembly to get `d`
> from `EDX` on x86 after division?
> 
> I also have some questions about other files (my.typetuple and
> my.traits): * I was confused with Phobos TypeTuple because it isn't a
> type tuple. Should it be replaced with some modification of my variant?
> * Have any additions in my.traits a general use? IMHO ArrayElementType,
> isType and staticRange have.
> 
> I also have some ideas (TODO-s) for my array which looks good: *
> opSliceAssign with an array or a RectangularArray as its operand should
> use array copy for as much tail dimensions as possible (if data has no
> copy constructor because of dmd bug 6470). * byElementRandomAccess
> should also look at all packed tail dimensions if they are one dimension
> for faster indexing. * Special optimized case for 2^^n-lengths.
> 
> 
> Thanks everybody for reading such a big post!





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