There were a few places where some const-casts were needed, but they're
localized to code that's supposed to manipulate types (but I do want to
come up with something to clean that up).
I'm not sure the regressive product is right (overall sign), but that's
actually partly a problem in the math itself (duals and the regressive
product still get poked at, so it may be just a matter of
interpretation).
This fixes the motor test :) It turns out that every lead I had
previously was due to the disabling of that feature "breaking" dags
(such that expressions wouldn't be found) and it was the dagged
multi-vector components getting linked by expr->next that made a mess of
things.
Or at least mostly so (there are a few casts). This doesn't fix the
motor bug, but I've wanted to do this for over twenty years and at least
I know what's not causing the bug. However, disabling fold_constants in
expr_algebra.c does "fix" things, so it's still a good place to look.
Simple k-vectors don't use structs for their layout since they're just
an array of scalars, but having the structs for group sets or full
multi-vectors makes the system alignment agnostic.
It's implemented as the Hodge dual, which is probably reasonable until
people complain. Both ⋆ and ! are supported, though the former is a
little hard to see in Consola.
Currently via only the group mask (which is really horrible to work
with: requires too much knowledge of implementation details, but does
the job for testing), but it got some basics working.
Also, correct the handling of scalars in dot and wedge products: it
turns out s.v and s^v both scale. However, it seems the CSE code loses
things sometimes.
This makes working with them much easier, and the type system reflects
what's in the multi-vector. Unfortunately, that does mean that large
algebras will wind up having a LOT of types, but it allows for efficient
storage of sparse multi-vectors:
auto v = 4*(e1 + e032 + e123);
results in:
0005 0213 1:0008<00000008>4:void 0:0000<00000000>?:invalid
0:0044<00000044>4:void assign (<void>), v
0006 0213 1:000c<0000000c>4:void 0:0000<00000000>?:invalid
0:0048<00000048>4:void assign (<void>), {v + 4}
Where the two source vectors are:
44:1 0 .imm float:18e [4, 0, 0, 0]
48:1 0 .imm float:1aa [4, 0, 0, 4]
They just happen to be adjacent, but don't need to be.
This gets only some very basics working:
* Algebra (multi-vector) types: eg @algebra(float(3,0,1)).
* Algebra scopes (using either the above or @algebra(TYPE_NAME) where
the above was used in a typedef.
* Basis blades (eg, e12) done via procedural symbols that evaluate to
suitable constants based on the basis group for the blade.
* Addition and subtraction of multi-vectors (only partially tested).
* Assignment of sub-algebra multi-vectors to full-algebra multi-vectors
(missing elements zeroed).
There's still much work to be done, but I thought it time to get
something into git.
