### `ufctrhint`

ufctrhint(poly,hint)
:: Factorizes uni-variate polynomial poly over the rational number field when the degrees of its factors are known to be some integer multiples of hint.
return
list
poly
uni-variate polynomial with rational coefficients
hint
non-negative integer
• By any reason, if the degree of all the irreducible factors of poly is known to be some multiples of hint, factors can be computed more efficiently by the knowledge than `fctr()`.
• When hint is 1, `ufctrhint()` is the same as `fctr()` for uni-variate polynomials. An typical application where `ufctrhint()` is effective: Consider the case where poly is a norm (See section Algebraic numbers) of a certain polynomial over an extension field with its extension degree d, and it is square free; Then, every irreducible factor has a degree that is a multiple of d.
```[10] A=t^9-15*t^6-87*t^3-125;
t^9-15*t^6-87*t^3-125
0msec
[11] N=res(t,subst(A,t,x-2*t),A);
-x^81+1215*x^78-567405*x^75+139519665*x^72-19360343142*x^69+1720634125410*x^66
-88249977024390*x^63-4856095669551930*x^60+1999385245240571421*x^57
-15579689952590251515*x^54+15956967531741971462865*x^51
...
+140395588720353973535526123612661444550659875*x^6
+10122324287343155430042768923500799484375*x^3
+139262743444407310133459021182733314453125
980msec + gc : 250msec
[12] sqfr(N);
[[-1,1],[x^81-1215*x^78+567405*x^75-139519665*x^72+19360343142*x^69
-1720634125410*x^66+88249977024390*x^63+4856095669551930*x^60
-1999385245240571421*x^57+15579689952590251515*x^54
...
-10122324287343155430042768923500799484375*x^3
-139262743444407310133459021182733314453125,1]]
20msec
[13] fctr(N);
[[-1,1],[x^9-405*x^6-63423*x^3-2460375,1],
[x^18-486*x^15+98739*x^12-9316620*x^9+945468531*x^6-12368049246*x^3
+296607516309,1],[x^18-8667*x^12+19842651*x^6+19683,1],
[x^18-324*x^15+44469*x^12-1180980*x^9+427455711*x^6+2793253896*x^3+31524548679,1],
[x^18+10773*x^12+2784051*x^6+307546875,1]]
167.050sec + gc : 1.890sec
[14] ufctrhint(N,9);
[[-1,1],[x^9-405*x^6-63423*x^3-2460375,1],
[x^18-486*x^15+98739*x^12-9316620*x^9+945468531*x^6-12368049246*x^3
+296607516309,1],[x^18-8667*x^12+19842651*x^6+19683,1],
[x^18-324*x^15+44469*x^12-1180980*x^9+427455711*x^6+2793253896*x^3+31524548679,1],
[x^18+10773*x^12+2784051*x^6+307546875,1]]
119.340sec + gc : 1.300sec
```
References
section `fctr`, `sqfr`.