iskolbin/lsparsematrix

Lua tiny sparse matrix library

Lua Sparse Matrix

Tiny lua sparse matrix library. Stores values in a flat table with metatable set. Coordinates are assumed to be numbers in the interval from -2^25 to 2^25. For Lua 5.3+ with 64-bit integers x, y can be in the interval from -2^31 to 2^31.

local SparseMatrix = require("sparsematrix")

-- Creation OOP-style (also works in pure procedural style)
local m = SparseMatrix.new({
	1, 5, 'x',
	5, -1, 'y',
})

-- Getting
assert(m:get(1,5) == 'x')
assert(m:get(5,-1) == 'y')
assert(m:get(0,0) == nil)

-- Inserting/deleting
m:set(-2, 3, 'z')
m:set(1, 5, nil)
assert(m:get(-2, 3) == 'z')
assert(m:get(1, 5) == nil)

-- Iteration
-- Should print
--   -2 3 z
--    5 -1 y
for _, x, y, v in m:iter() do
	print(x, y, v)
end 

SparseMatrix.make([xyvs])

Create plain lua table and fill it as a sparse matrix with values from xyvs which is flat table containing triples x, y, v.

SparseMatrix.new([xyvs])

Create new sparse matrix and fill it with values from xyvs. Internally it's make followed with setmetatable.

SparseMatrix:set(x, y, [v])

Sets sparse matrix value at x, y to v(or nil if omitted).

SparseMatrix:get(x, y, [default])

Returns value at x, y or default if there is no value(or nil if omitted).

SparseMatrix:iter()

Returns iterator pair for general for, generates 4 values: key, x, y, v.

SparseMatrix:next(prevk)

Returns key, x, y, v after key prevk (if omitted returns first quartet), used mainly internally for iter.