Talk:Absolute difference

arm neon instruction

Is it worth noting that the ARM CPU has a absolute difference instruction. http://infocenter.arm.com/help/topic/com.arm.doc.dui0491c/BABEDJFB.html

There are expressions used as absolute differences and their squares.

(u₁ + u₂)(v₁ + v₂)(u₁ + v₁)(u₂ + v₂) – (u₁ + u₂ + v₁ + v₂)(u₁u₂v₁ + u₁u₂v₂ + u₁v₁v₂ + u₂v₁v₂) = (u₁v₂ – u₂v₁)²
√(u₁ + u₂)(v₁ + v₂)(u₁ + v₁)(u₂ + v₂) – (u₁ + u₂ + v₁ + v₂)(u₁u₂v₁ + u₁u₂v₂ + u₁v₁v₂ + u₂v₁v₂) = |u₁v₂ – u₂v₁|
(E₁ + E₂)(R₁ + R₂)(E₁ + R₁)(E₂ + R₂) – (E₁ + E₂ + R₁ + R₂)(E₁E₂R₁ + E₁E₂R₂ + E₁R₁R₂ + E₂R₁R₂) = (E₁R₂ – E₂R₁)²
√(E₁ + E₂)(R₁ + R₂)(E₁ + R₁)(E₂ + R₂) – (E₁ + E₂ + R₁ + R₂)(E₁E₂R₁ + E₁E₂R₂ + E₁R₁R₂ + E₂R₁R₂) = |E₁R₂ – E₂R₁|
(x₁ + x₂)(y₁ + y₂)(x₁ + y₁)(x₂ + y₂) – (x₁ + x₂ + y₁ + y₂)(x₁x₂y₁ + x₁x₂y₂ + x₁y₁y₂ + x₂y₁y₂) = (x₁y₂ – x₂y₁)²
√(x₁ + x₂)(y₁ + y₂)(x₁ + y₁)(x₂ + y₂) – (x₁ + x₂ + y₁ + y₂)(x₁x₂y₁ + x₁x₂y₂ + x₁y₁y₂ + x₂y₁y₂) = |x₁y₂ – x₂y₁|
(m + n)(p + q)(m + p)(n + q) – (m + n + p + q)(mnp + mnq + mpq + npq) = (mq – np)²
√(m + n)(p + q)(m + p)(n + q) – (m + n + p + q)(mnp + mnq + mpq + npq) = |mq – np|