Starting with polynomial:
P : 4*t^3 - 3*t
Extension levels are: 3 4
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Trying to find an order 4 Kronrod extension for:
P1 : 4*t^3 - 3*t
Solvable: 1
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Ending with final polynomial:
P : 4*t^7 - 8*t^5 + 19/4*t^3 - 3/4*t
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Computing nodes and weights
  current precision for roots: 53
  current precision for roots: 106
 current precision for weights: 53
Linear system for weights solvable: 1
  current precision for roots: 106
  current precision for roots: 212
 current precision for weights: 106
Linear system for weights solvable: 1
Sufficient bits for target precision reached
Positive weights:   7 out of 7
Indefinite weights: 0 out of 7
Negative weights:   0 out of 7
Extension rule has valid weights: 1
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The nodes are:
| (1 - 7.3476769926515033223e-140j)  +/-  (2.13e-62, 2.13e-62j)
| (-0.86602540378443864676 - 2.7968777742000775287e-155j)  +/-  (2.56e-62, 2.56e-62j)
| (-1 + 5.6857142980577740874e-175j)  +/-  (2.13e-62, 2.13e-62j)
| (-0.5 - 9.7676843897697997097e-187j)  +/-  (2.53e-63, 2.53e-63j)
| (0.5 - 1.5710889413692232989e-189j)  +/-  (2.53e-63, 2.53e-63j)
| (0.86602540378443864676 + 5.7863766813821840249e-191j)  +/-  (2.56e-62, 2.56e-62j)
| (-3.2106582260865278903e-196 + 1.0702194086955092968e-195j)  +/-  (7.82e-195, 7.82e-195j)
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The weights are:
| (0.083333333333333333333 + 7.4497280619938854378e-140j)  +/-  (2.99e-27, 1.28e-57j)
| (0.16666666666666666667 - 6.5626803880856940733e-141j)  +/-  (1.32e-27, 5.66e-58j)
| (0.083333333333333333333 + 3.0615320802714423208e-141j)  +/-  (8.32e-28, 3.56e-58j)
| (0.16666666666666666667 + 8.1640855473905719823e-141j)  +/-  (3.8e-28, 1.66e-58j)
| (0.16666666666666666667 + 2.4492256642171681153e-140j)  +/-  (1.83e-28, 7.68e-59j)
| (0.16666666666666666667 - 9.1406346180601011508e-140j)  +/-  (1.67e-28, 6.78e-59j)
| (0.16666666666666666667 - 1.2246128321085844253e-140j)  +/-  (1.11e-28, 4.92e-59j)
