## rd_GL(n,F) : random invertible matrix of order n with entries in F


from PyM import *

# def rd_GL(n,F=Zn(2)):
#     a = rd_nonzero(F) 
#     A = matrix([a])
#     for _ in range(2,n+1):
#         A = rd_extend(A)
#     return A

# def rd_extend(A):
#     k = ncols(A); F = K_(A)
#     v = rd_nonzero_vector(F,k+1)
#     r = 0
#     for j in range(k+1):
#         if v[j]!=0: 
#             r = j; break
#     A = rd_insert(A,r)
#     x = v[r]
#     for j in range(r+1,k+1):
#         A[:,j] = A[:,j]+ A[:,r]*v[j]
#     A[:,r] = x*A[:,r]
#     return A
# 
# def rd_insert(A,r):
#     n = ncols(A)
#     if r<0 or r>n: return "r has to be in 0..n"
#     K = K_(A)
#     B = matrix(K,n+1,n+1)
#     B[0,r] = 1
#     for j in range(1,n+1):
#         B[j,r] = rd(K)
#     if r==0:
#         B[1:,1:] = A[:,:]
#     elif r==n:
#         B[1:,0:n] = A[:,:] 
#     else:
#        B[1:,0:r] = A[:,0:r] 
#        B[1:,r+1:n+1] = A[:,r:n] 
#     return B

show(rd_GL(7))

show(rd_GL(7,Zn(83)))