Starting with polynomial:
P : t^8 - 28*t^6 + 210*t^4 - 420*t^2 + 105
Extension levels are: 8 11
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Trying to find an order 11 Kronrod extension for:
P1 : t^8 - 28*t^6 + 210*t^4 - 420*t^2 + 105
Solvable: 1
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Ending with final polynomial:
P : t^19 - 150851/1347*t^17 + 6541430/1347*t^15 - 47540390/449*t^13 + 566981260/449*t^11 - 3753992440/449*t^9 + 13180991670/449*t^7 - 21510616050/449*t^5 + 12604959675/449*t^3 - 2144332575/449*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:   15 out of 19
Indefinite weights: 0 out of 19
Negative weights:   4 out of 19
Extension rule has valid weights: 0
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*** EXTENSION WITH INVALID WEIGHTS ***
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