Starting with polynomial:
P : 8*t^3 - 12*t
Extension levels are: 3 6 12
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Trying to find an order 6 Kronrod extension for:
P1 : 8*t^3 - 12*t
Solvable: 1
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Trying to find an order 12 Kronrod extension for:
P2 : 8*t^9 - 117*t^7 + 945/2*t^5 - 2205/4*t^3 + 945/8*t
Solvable: 1
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Ending with final polynomial:
P : 8*t^21 - 20774971893/33300373*t^19 + 653412876723/33300373*t^17 - 86530745663355/266402984*t^15 + 1652267603793375/532805968*t^13 - 18783353149157025/1065611936*t^11 + 127015854640073685/2131223872*t^9 - 497343697084550745/4262447744*t^7 + 1061381742497601525/8524895488*t^5 - 1073644320567443625/17049790976*t^3 + 341241276683382075/34099581952*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: 0
  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:   19 out of 21
Indefinite weights: 0 out of 21
Negative weights:   2 out of 21
Extension rule has valid weights: 0
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*** EXTENSION WITH INVALID WEIGHTS ***
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