sympy.polys.polyerrors.NotAlgebraic Exception

[proy87]

factor(-exp(x)*tan(pi/7) + 1, extension=True)
Without the extension flag everything is OK.

[oscarbenjamin]

This works fine on master:

In [1]: factor(-exp(x)*tan(pi/7) + 1, extension=True)
Out[1]: 
 ⎛                   5⎛π⎞            ⎞       
 ⎜                tan ⎜─⎟            ⎟       
 ⎜ x        ⎛π⎞       ⎝7⎠        3⎛π⎞⎟    ⎛π⎞
-⎜ℯ  - 5⋅tan⎜─⎟ - ─────── + 3⋅tan ⎜─⎟⎟⋅tan⎜─⎟
 ⎝          ⎝7⎠      7            ⎝7⎠⎠    ⎝7⎠

In [2]: factor(-exp(x)*tan(pi/7) + 1)
Out[2]: 
   x    ⎛π⎞    
- ℯ ⋅tan⎜─⎟ + 1
        ⎝7⎠   

Seems to have been fixed in cc7e4c7 from #21442

[proy87]

@oscarbenjamin , I thought that extension works only on factoring binomials, not coefficients. Is there any way I can factor x**2+1 into (x-I)(x+I), but leave Ix-1 unchanged? If I add extension=True, then Ix-1 is factored as I(Ix+I).

[oscarbenjamin]

When factor is used with an extension field it seems it always factors into monic irreducibles and separates out the coefficient.