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Update to support n-vector and casting other table-like types #4

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Update to support n-vector and casting other table-like types #4

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42 changes: 32 additions & 10 deletions lua/matrix.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -108,13 +108,14 @@ LICENSE
Developers:
Michael Lutz (chillcode) - original author
David Manura http://lua-users.org/wiki/DavidManura

--]]

--////////////
--// matrix //
--////////////

local matrix = {_TYPE='module', _NAME='matrix', _VERSION='0.2.11.20120416'}
local matrix = {_TYPE='module', _NAME='matrix', _VERSION='0.2.12.20131208'}

-- access to the metatable we set at the end of the file
local matrix_meta = {}
Expand All @@ -129,14 +130,23 @@ local matrix_meta = {}
-- if rows and columns are given and are numbers, returns a matrix with size rowsxcolumns
-- if num is given then returns a matrix with given size and all values set to num
-- if rows is given as number and columns is "I", will return an identity matrix of size rowsxrows
-- is rows is a table with `astable` defined, sets row:astable() as matrix
function matrix:new( rows, columns, value )
-- check for given matrix
if type( rows ) == "table" then
-- check for vector
if type(rows[1]) ~= "table" then -- expect a vector
return setmetatable( {{rows[1]},{rows[2]},{rows[3]}},matrix_meta )
local m = {}
for k, v in ipairs(rows) do
m[k] = {v}
end
return setmetatable( m,matrix_meta )
end
return setmetatable( rows,matrix_meta )
if rows.astable then
return setmetatable( rows:astable(),matrix_meta )
else
return setmetatable( rows,matrix_meta )
end
end
-- get matrix table
local mtx = {}
Expand Down Expand Up @@ -981,29 +991,40 @@ end
--// matrix 'vector' functions //
--///////////////////////////////

-- a vector is defined as a 3x1 matrix
-- get a vector; vec = matrix{{ 1,2,3 }}^'T'
-- a vector is defined as a Nx1 matrix
-- get a vector; vec = matrix{ 1,2,3 }

--// matrix.scalar ( m1, m2 )
-- returns the Scalar Product of two 3x1 matrices (vectors)
-- returns the Scalar Product of two Nx1 matrices (vectors)
function matrix.scalar( m1, m2 )
return m1[1][1]*m2[1][1] + m1[2][1]*m2[2][1] + m1[3][1]*m2[3][1]
local s=0
for i=1, #m1 do
s = s + m1[i][1]*m2[i][1]
end
return s
end

--// matrix.cross ( m1, m2 )
-- returns the Cross Product of two 3x1 matrices (vectors)
-- returns the Cross Product of two 3x1 or 4x1 matrices (vectors)
function matrix.cross( m1, m2 )
local mtx = {}
mtx[1] = { m1[2][1]*m2[3][1] - m1[3][1]*m2[2][1] }
mtx[2] = { m1[3][1]*m2[1][1] - m1[1][1]*m2[3][1] }
mtx[3] = { m1[1][1]*m2[2][1] - m1[2][1]*m2[1][1] }
if m1[4] then
mtx[4] = 0
end
return setmetatable( mtx, matrix_meta )
end

--// matrix.len ( m1 )
-- returns the Length of a 3x1 matrix (vector)
-- returns the Length of a Nx1 matrix (vector)
function matrix.len( m1 )
return math.sqrt( m1[1][1]^2 + m1[2][1]^2 + m1[3][1]^2 )
local s=0
for i=1, #m1 do
s = s + m1[i][1]^2
end
return math.sqrt(s)
end


Expand Down Expand Up @@ -1249,3 +1270,4 @@ return matrix
--///////////////--
--// chillcode //--
--///////////////--