copy -- vector copy
   -1 -- local copy (A = B))
   -5 -- local copy (memcpy))
 Using assignment (A = B):
  -10 -- float root copy      (root -> root)
  -11 -- float scatter        (root -> all)
  -12 -- float gather         (all  -> root)
  -13 -- float dist copy      (all  -> all)
  -14 -- float point-to-point (p0   -> p1)
  -15 -- float scatter2       (root -> all non-root)
 Using Setup_assign:
  -20 -- float root copy      (root -> root)
  -21 -- float scatter        (root -> all)
  -22 -- float gather         (all  -> root)
  -23 -- float dist copy      (all  -> all)
  -24 -- float point-to-point (p0   -> p1)
  -25 -- float scatter2       (root -> all non-root)

 MPI low-level Par_assign directly:
  -100-105 -- Chained_assign
  -110-115 -- Blkvec_assign
  -150-155 -- Chained_assign (non-amortized setup)
  -160-165 -- Blkvec_assign (non-amortized setup)

 PAS low-level Par_assign directly:
  -200-205 -- Pas_assign
  -210-215 -- Pas_assign_eb
  -220-225 -- Direct_pas_assign
  -250-255 -- Pas_assign (non-amortized setup)
  -260-265 -- Pas_assign_eb (non-amortized setup)
  -270-275 -- Direct_pas_assign (non-amortized setup)