Here are the operations you can use inside the function you are compiling.
Some Python control flow statements are not supported. For example, you cannot have an
ifstatement or a
whilestatement for which the condition depends on an encrypted value. However, such statements are supported with constant values (e.g.,
for i in range(SOME_CONSTANT),
if os.environ.get("SOME_FEATURE") == "ON":).
Another constraint is that you cannot have floating-point inputs or floating-point outputs. You can have floating-point intermediate values as long as they can be converted to an integer Table Lookup (e.g.,
(60 * np.sin(x)).astype(np.int64)).
There is a limit on the bit width of encrypted values. We are constantly working on increasing this bit width. If you go above this limit, you will get an error.
One of the most common operations in Concrete Numpy is
Table Lookups(TLUs). TLUs are performed with an FHE operation called
Programmable Bootstrapping(PBS). PBSes have a certain probability of error, which, when triggered, result in inaccurate results.
Let's say you have the table:
[1, 4, 9, 16, 25, 36, 49, 64]
And you performed a table lookup using
4, The result you should get is
16, but because of the possibility of error, you can sometimes get