Function: nfsolvemodpr
Section: number_fields
C-Name: nfsolvemodpr
Prototype: GGGG
Help: nfsolvemodpr(nf,a,b,P): solution of a*x=b in Z_K/P, where a is a
 matrix and b a column vector, and where P is in modpr format (see
 nfmodprinit).
Doc: let $P$ be a prime ideal in \key{modpr} format (see \kbd{nfmodprinit}),
 let $a$ be a matrix, invertible over the residue field, and let $b$ be
 a column vector or matrix. This function returns a solution of $a\cdot x =
 b$; the coefficients of $x$ are lifted to \var{nf} elements.
 \bprog
 ? K = nfinit(y^2+1);
 ? P = idealprimedec(K, 3)[1];
 ? P = nfmodprinit(K, P);
 ? a = [y+1, y; y, 0]; b = [1, y]~
 ? nfsolvemodpr(K, a,b, P)
 %5 = [1, 2]~
 @eprog
Variant: This function is normally useless in library mode. Project your
 inputs to the residue field using \kbd{nfM\_to\_FqM}, then work there.
