///|
/// Construct point-cloud costs, solve a transport problem, and project target
/// coordinates back to each source point through the conditional coupling.
fn main {
  let source_points = [[0.0], [2.0]]
  let target_points = [[0.0], [2.0]]
  match @moonot.squared_euclidean_cost_matrix(source_points, target_points) {
    Err(_) => println("invalid point-cloud inputs")
    Ok(cost) =>
      match
        @moonot.balanced_sinkhorn([0.4, 0.6], [0.2, 0.8], cost, {
          epsilon: 0.2,
          tolerance: 1.0e-9,
          max_iterations: 2000,
        }) {
        Err(_) => println("transport solve did not accept the inputs")
        Ok(solution) => {
          println("point-cloud squared-distance cost matrix:")
          for i in 0.. println("target projection is undefined or invalid")
            Ok(projected) => {
              println("conditional target coordinate by source point:")
              for i in 0..