How to encode an array of numbers in python with piheean?

I have this code which encrypts a list of numbers.

import piheaan as heaan
import numpy as np

# Step 1. Setting Parameters
params = heaan.ParameterPreset.SS7
context = heaan.make_context(params)
# Step 2. Generating Keys
key_dir_path = "./keys"
sk = heaan.SecretKey(context)
keygen = heaan.KeyGenerator(context, sk)
keygen.gen_common_keys()
pack = keygen.keypack
# Step 3. Encrypt Message to Ciphertext - with a specific vector
enc = heaan.Encryptor(context)
log_slots = 3
msg = heaan.Message(log_slots) # number_of slots = pow(2, log_slots)
for i, value in  in enumerate([2,5,4,3]):
    msg[i] = value
ctxt = heaan.Ciphertext(context)
enc.encrypt(msg, pack, ctxt)
# Step 4. multiply ciphertexts(i.e. square a ciphertext)
eval = heaan.HomEvaluator(context, pack)
ctxt_out = heaan.Ciphertext(context)
eval.mult(ctxt, ctxt, ctxt_out)
# Step 5. decrypt the ciphertext by Decryptor.
dec = heaan.Decryptor(context)
msg_out = heaan.Message()
dec.decrypt(ctxt_out, sk, msg_out)

#output - it has 9 slots (2 to the power of 3), so only encrypts the first 4 in this case.
msg_out
[ (4.000000+0.000000j), (25.000000+0.000000j), (16.000000+0.000000j), (9.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j) ]

However, my actual data is in the form of an array, e.g.:

l1 = [2, 5, 4, 3]
l2 = [1, 2, 2, 3]
..

arr_in = np.array([l1,l2])
arr_in
# array([[2, 5, 4, 3],
#       [1, 2, 2, 3]])

I have tried this

for i, value in np.ndenumerate(arr):
    msg[i] = value

but it does not work with the piheean's message format giving an error.

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Input In [44], in <cell line: 5>()
      4 msg = heaan.Message(log_slots) # number_of slots = pow(2, log_slots)
      5 for i, value in np.ndenumerate(arr):
----> 6     msg[i] = value
      7 ctxt = heaan.Ciphertext(context)
      8 enc.encrypt(msg, pack, ctxt)

TypeError: __setitem__(): incompatible function arguments. The following argument types are supported:
    1. (self: piheaan.Message, idx: int, value: complex) -> None

Invoked with: [ (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j) ], (0, 0), 2

how can I write the code which essentially takes each list from my array, arr_in, encrypts it and outputs it as an array of the form, arr_out, array([[4, 25,16,9], [1,4,4,9]]) ?

If you print this :

for i, value in np.ndenumerate(arr_in):
print(i,value)
(0, 0) 2
(0, 1) 1
(0, 2) 5
(0, 3) 2
(1, 0) 4
(1, 1) 2
(1, 2) 3
(1, 3) 3

You were trying to assign (0,0)..(1,3) tuples to msg[]. That is the reason you were getting error.

Instead you can do:

l1 = [2, 5, 4, 3]
l2 = [1, 2, 2, 3]
arr_in = np.array(list(zip(l1, l2))).reshape((2, 4))
#output
array([[2, 1, 5, 2],
[4, 2, 3, 3]])
new_arr = arr_in.flatten()
for i,value in enumerate(new_arr):
print(i,value)  # you get the index as well as the value
0 2
1 1
2 5
3 2
4 4
5 2
6 3
7 3

msg is 2**3 .i.e. 8 values

[ (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j), (0.000000+0.000000j) ]
for i, value in enumerate(new_arr):
msg[i] = value
print(msg)
[ (2.000000+0.000000j), (1.000000+0.000000j), (5.000000+0.000000j), (2.000000+0.000000j), (4.000000+0.000000j), (2.000000+0.000000j), (3.000000+0.000000j), (3.000000+0.000000j) ]