Starting with polynomial:
P : t
Extension levels are: 1 6 8
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Trying to find an order 6 Kronrod extension for:
P1 : t
Solvable: 1
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Trying to find an order 8 Kronrod extension for:
P2 : t^7 - 21/13*t^5 + 105/143*t^3 - 35/429*t
Solvable: 1
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Ending with final polynomial:
P : t^15 - 825/221*t^13 + 336705/60401*t^11 - 8310395/1960287*t^9 + 8381629155/4854324041*t^7 - 250360401/693474863*t^5 + 300170185/9015173219*t^3 - 88221135/99166905409*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
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The nodes are:
| (0.99145537112081263921 + 1.0948923785000873547e-199j)  +/-  (1.21e-59, 1.21e-59j)
| (-0.2077849550078984676 - 1.9122307746914205256e-212j)  +/-  (6.55e-63, 6.55e-63j)
| (-0.74153118559939443986 + 6.7072886823351107523e-210j)  +/-  (5.28e-60, 5.28e-60j)
| (0.40584515137739716691 - 5.81559505021444155e-212j)  +/-  (9.65e-62, 9.65e-62j)
| (0.94910791234275852453 + 1.4513645926434610778e-209j)  +/-  (2.49e-59, 2.49e-59j)
| (0.74153118559939443986 - 5.895948194114551302e-214j)  +/-  (5.33e-60, 5.33e-60j)
| (-0.40584515137739716691 - 3.1260911344922069119e-220j)  +/-  (8.14e-62, 8.14e-62j)
| (-0.86486442335976907279 + 6.6826865149889618511e-216j)  +/-  (1.41e-59, 1.41e-59j)
| (-0.94910791234275852453 - 1.0527568360037189266e-216j)  +/-  (2.42e-59, 2.42e-59j)
| (0.58608723546769113029 + 4.6609188879579382347e-218j)  +/-  (7.74e-61, 7.74e-61j)
| (0.86486442335976907279 + 3.0093047051557806816e-227j)  +/-  (1.62e-59, 1.62e-59j)
| (1.79061400064236103e-235 + 1.8551129612143843261e-235j)  +/-  (3.87e-234, 3.87e-234j)
| (-0.99145537112081263921 - 7.6130887404326468819e-233j)  +/-  (1.23e-59, 1.23e-59j)
| (-0.58608723546769113029 + 2.6934554777565531949e-238j)  +/-  (8.32e-61, 8.32e-61j)
| (0.2077849550078984676 + 2.32453006153822798e-238j)  +/-  (6.55e-63, 6.55e-63j)
-------------------------------------------------
The weights are:
| (0.022935322010529224964 - 1.1624914727807189564e-199j)  +/-  (7.87e-19, 2.23e-47j)
| (0.20443294007529889241 - 1.8664488103692927463e-200j)  +/-  (3.02e-19, 8.54e-48j)
| (0.14065325971552591875 + 8.7852452575106420135e-201j)  +/-  (9.96e-20, 2.82e-48j)
| (0.19035057806478540991 + 3.5800163303880148094e-200j)  +/-  (1.15e-19, 3.25e-48j)
| (0.063092092629978553291 + 1.7165859137806224302e-199j)  +/-  (1.13e-19, 3.2e-48j)
| (0.14065325971552591875 + 6.0917321368510996173e-200j)  +/-  (6.3e-20, 1.78e-48j)
| (0.19035057806478540991 + 1.5003888688603970634e-200j)  +/-  (5.64e-20, 1.6e-48j)
| (0.10479001032225018384 - 6.1807121738480691565e-201j)  +/-  (4.31e-21, 1.22e-49j)
| (0.063092092629978553291 + 3.7459768404593363067e-201j)  +/-  (1.07e-21, 3.03e-50j)
| (0.16900472663926790283 - 4.5647886656646301557e-200j)  +/-  (1.34e-20, 3.75e-49j)
| (0.10479001032225018384 - 9.0633481819078566266e-200j)  +/-  (1.42e-20, 3.99e-49j)
| (0.20948214108472782801 + 2.3022713039919398035e-200j)  +/-  (2.8e-21, 7.98e-50j)
| (0.022935322010529224964 - 1.2664064356127040815e-201j)  +/-  (1.44e-22, 4.16e-51j)
| (0.16900472663926790283 - 1.1729761620855411328e-200j)  +/-  (8e-22, 2.33e-50j)
| (0.20443294007529889241 - 2.8562015789140858784e-200j)  +/-  (1.02e-21, 2.67e-50j)
