Module: Gsplat::Backend::RubyQuatScaleToCovarPreci

Defined in:
lib/gsplat/backend/ruby/quat_scale_to_covar_preci.rb

Overview

Numo implementation of quaternion/scale covariance conversion.

Class Method Summary collapse

Class Method Details

.backward(quaternions, scales, grad_covar, grad_preci, triu:) ⇒ Object 



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# File 'lib/gsplat/backend/ruby/quat_scale_to_covar_preci.rb', line 22

def backward(quaternions, scales, grad_covar, grad_preci, triu:)
  quaternions, scales, leading_shape = validate_inputs(quaternions, scales, !grad_preci.nil?)
  count = quaternions.size / 4
  rotations = Math::Quaternion.to_rotmat(quaternions).reshape(count, 3, 3)
  scales_flat = scales.reshape(count, 3)
  grad_rotations = quaternions.class.zeros(count, 3, 3)
  grad_scales = quaternions.class.zeros(count, 3)
  if grad_covar
    accumulate_covar_gradients!(
      grad_rotations,
      grad_scales,
      rotations,
      scales_flat,
      expand_gradient(grad_covar, leading_shape, triu, quaternions.class)
    )
  end
  if grad_preci
    accumulate_preci_gradients!(
      grad_rotations,
      grad_scales,
      rotations,
      scales_flat,
      expand_gradient(grad_preci, leading_shape, triu, quaternions.class)
    )
  end
  grad_quaternions = Math::Quaternion.to_rotmat_vjp(
    quaternions,
    grad_rotations.reshape(*(leading_shape + [3, 3]))
  )
  [grad_quaternions, grad_scales.reshape(*(leading_shape + [3]))]
end

.forward(quaternions, scales, compute_covar:, compute_preci:, triu:) ⇒ Object 



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# File 'lib/gsplat/backend/ruby/quat_scale_to_covar_preci.rb', line 9

def forward(quaternions, scales, compute_covar:, compute_preci:, triu:)
  quaternions, scales, leading_shape = validate_inputs(quaternions, scales, compute_preci)
  count = quaternions.size / 4
  rotations = Math::Quaternion.to_rotmat(quaternions).reshape(count, 3, 3)
  scales_flat = scales.reshape(count, 3)
  covariance = covariance_matrix(rotations, scales_flat) if compute_covar
  precision = precision_matrix(rotations, scales_flat) if compute_preci
  [
    format_output(covariance, leading_shape, triu),
    format_output(precision, leading_shape, triu)
  ]
end