Bug in random OMS

[rpollack9974]

This bug I think is at the heart of the problems with issue #21.

sage: D = OverconvergentDistributions(0,7,base=Qp(7,5)) sage: MS = OverconvergentModularSymbols(14,sign=1,coefficients=D); MS Space of overconvergent modular symbols for Congruence Subgroup Gamma0(14) with sign 1 and values in Space of 7-adic distributions with k=0 action and precision cap 5 sage: Phi = MS.random_element() sage: Phi._consistency_check() (4 + 7 + 6_7^2 + 6_7^3 + 2_7^4 + O(7^5), 5 + 5_7 + 3_7^2 + 3_7^3 + O(7^4), 2 + 5*7 + 7^2 + O(7^3), 6 + O(7^2), 5 + O(7))

(3_7 + 4_7^2 + 7^3 + 4_7^4 + O(7^5), 2 + 3_7 + 2_7^2 + 4_7^3 + O(7^4), 3 + 7 + O(7^3), 1 + O(7^2), 6 + O(7))

ValueError Traceback (most recent call last)

in () ----> 1 Phi._consistency_check() /Applications/sage-5.7/local/lib/python2.7/site-packages/sage/modular/pollack_stevens/modsym_OMS_element.pyc in _consistency_check(self) 181 print -t 182 print f[id]*MR.gammas[id] - f[id] --> 183 raise ValueError("Does not add up correctly around loop") 184 185 print "This modular symbol satisfies the manin relations" ValueError: Does not add up correctly around loop Also note that these random symbols seem to always have positive valuation: sage: Phi = MS.random_element() sage: Phi.valuation() 1 sage: Phi = MS.random_element() sage: Phi.valuation() 1 sage: Phi = MS.random_element() sage: Phi.valuation() 1 sage: Phi = MS.random_element() sage: Phi.valuation() 1

[rharron]

Re the valuation: I had noticed this yesterday. This is happening because the valuation of mu is being determined before reducing its precision, i.e. there is a unit value at some moment in the extra precision we're working in, that drops out once we project back down to our desired precision. I left this in because I wasn't too worried about it.

[rharron]

I think I've fixed these bugs, I'm just trying to make sure.

[rharron]

Yup, looks fixed. The above example you gave works.