Ruby/Number/matrix
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Содержание[убрать] |
matrix in action
require "matrix" # Represent the point (1,1) as the vector [1,1] unit = Vector[1,1] identity = Matrix.identity(2) # 2x2 matrix identity*unit == unit # true: no transformation
This matrix rotates counterclockwise around the origin
require "matrix" unit = 2 theta = Math::PI/2 # 90 degrees rotate = Matrix[[Math.cos(theta), -Math.sin(theta)], [Math.sin(theta), Math.cos(theta)]] rotate*unit # [-1.0, 1.0]: 90 degree rotation
This matrix scales a point by sx,sy
require "matrix" unit = 2 sx,sy = 2.0, 3.0; scale = Matrix[[sx,0], [0, sy]] scale*unit # => [2.0, 3.0]: scaled point
Two transformations in one
require "matrix" sx,sy = 2.0, 3.0; unit = 2 scale = Matrix[[sx,0], [0, sy]] scale*unit # => [2.0, 3.0]: scaled point theta = Math::PI/2 # 90 degrees rotate = Matrix[[Math.cos(theta), -Math.sin(theta)], [Math.sin(theta), Math.cos(theta)]] rotate*unit # [-1.0, 1.0]: 90 degree rotation scale * (rotate*unit) # [-2.0, 3.0]
