Starting with polynomial:
P : 8*t^3 - 12*t
Extension levels are: 3 18
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Trying to find an order 18 Kronrod extension for:
P1 : 8*t^3 - 12*t
Solvable: 1
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Ending with final polynomial:
P : 8*t^21 - 12952203/17084*t^19 + 987853833/34168*t^17 - 9840668841/17084*t^15 + 222748598835/34168*t^13 - 5840004786525/136672*t^11 + 43360655152815/273344*t^9 - 85340399389245/273344*t^7 + 155352674512035/546688*t^5 - 385274669454675/4373504*t^3 + 24027902323425/8747008*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
  current precision for roots: 212
  current precision for roots: 424
 current precision for weights: 212
Linear system for weights solvable: 1
Sufficient bits for target precision reached
Positive weights:   20 out of 21
Indefinite weights: 0 out of 21
Negative weights:   1 out of 21
Extension rule has valid weights: 0
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*** EXTENSION WITH INVALID WEIGHTS ***
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