Using numba in a method to randomize matrices - numba

Question

I'm still not very familiar with numba and my problem is that I have the piece of code bellow that I use for randomize the edges of graphs.
This code is simply used to swap some edges in a connectivity matrix given the number of desired swaps and a seed for the random number generator.
My problem is that when I try to use it with numba to speed it up I did not menage to run it. The error it returns is also pasted bellow.
#nb.jit(nopython=True)
def _randomize_adjacency_wei(A, n_swaps, seed):
np.random.seed(seed)
# Number of nodes
n_nodes = A.shape[0]
# Copy the adj. matrix
Arnd = A.copy()
# Choose edges that will be swaped
edges = np.random.choice(n_nodes, size=(4, n_swaps), replace=True).T
#itr = range(n_swaps)
#for it in tqdm(itr) if verbose else itr:
it = 0
for it in range(n_swaps):
i,j,k,l = edges[it,:]
if len(np.unique([i,j,k,l]))<4:
continue
else:
# Old values of weigths
w_ij,w_il,w_kj,w_kl=Arnd[i,j],Arnd[i,l],Arnd[k,j],Arnd[k,l]
# Swaping edges
Arnd[i,j]=Arnd[j,i]=w_il
Arnd[k,l]=Arnd[l,k]=w_kj
Arnd[i,l]=Arnd[l,i]=w_ij
Arnd[k,j]=Arnd[j,k]=w_kl
return Arnd
TypingError: Failed in nopython mode pipeline (step: nopython frontend)
No implementation of function Function(<function unique at 0x7f1a1c03b0d0>) found for signature:
>>> unique(list(int64)<iv=None>)
There are 2 candidate implementations:
- Of which 2 did not match due to:
Overload in function 'np_unique': File: numba/np/arrayobj.py: Line 1915.
With argument(s): '(list(int64)<iv=None>)':
Rejected as the implementation raised a specific error:
TypingError: Failed in nopython mode pipeline (step: nopython frontend)
Unknown attribute 'ravel' of type list(int64)<iv=None>
File "../../../home/vinicius/anaconda3/lib/python3.8/site-packages/numba/np/arrayobj.py", line 1918:
def np_unique_impl(a):
b = np.sort(a.ravel())
^
During: typing of get attribute at /home/vinicius/anaconda3/lib/python3.8/site-packages/numba/np/arrayobj.py (1918)
File "../../../home/vinicius/anaconda3/lib/python3.8/site-packages/numba/np/arrayobj.py", line 1918:
def np_unique_impl(a):
b = np.sort(a.ravel())
^
raised from /home/vinicius/anaconda3/lib/python3.8/site-packages/numba/core/typeinfer.py:1071
During: resolving callee type: Function(<function unique at 0x7f1a1c03b0d0>)
During: typing of call at <ipython-input-165-90ffd30fe0e8> (19)
File "<ipython-input-165-90ffd30fe0e8>", line 19:
def _randomize_adjacency_wei(A, n_swaps, seed):
<source elided>
i,j,k,l = edges[it,:]
if len(np.unique([i,j,k,l]))<4:
^
Thanks in advance,
Vinicius

Answer 1

According to the comments, you are passing a list to np.unique() but this is not supported by Numba.
Modifying the code this way:
i, j, k, l = e = edges[it, :]
if len(np.unique(e)) < 4:
...
The following example doesn't produce any errors:
>>> A = np.random.randint(0, 5, (8,8))
>>> r = _randomize_adjacency_wei(A, 4, 33)