pcubic_test
  Test pcubic().
    0.7000000E+01    0.6400000E+02
    0.2500000E+01   -0.1250000E+00
    0.5500000E+01    0.1562500E+02
    0.1500000E+01   -0.3375000E+01
    0.0000000E+00   -0.2700000E+02