fix(gpu): fix cornercase in match value function

tfhe/src/integer/gpu/server_key/radix/vector_find.rs

@@ -22,6 +22,9 @@ impl CudaServerKey {
         selectors: &[CudaBooleanBlock],
         streams: &CudaStreams,
     ) -> CudaUnsignedRadixCiphertext {
+        if selectors.len() == 0 {
+            return self.create_trivial_radix(0, 1, streams);
+        }
         let packed_list = CudaLweCiphertextList::from_vec_cuda_lwe_ciphertexts_list(
             selectors
                 .iter()
@@ -46,6 +49,9 @@ impl CudaServerKey {
     where
         T: CudaIntegerRadixCiphertext,
     {
+        if radixes.len() == 0 {
+            return self.create_trivial_radix(0, 1, streams);
+        }
         let packed_list = CudaLweCiphertextList::from_vec_cuda_lwe_ciphertexts_list(
             radixes.iter().map(|ciphertext| &ciphertext.d_blocks),
             streams,
@@ -155,9 +161,8 @@ impl CudaServerKey {
             //
             // Thus in that case, the returned value is always 0 regardless of ct's value,
             // but we still have to see if the input matched something
-            let zero_ct: CudaUnsignedRadixCiphertext = unsafe {
-                self.create_trivial_zero_radix_async(num_blocks_to_represent_values, streams)
-            };
+            let zero_ct: CudaUnsignedRadixCiphertext =
+                unsafe { self.create_trivial_zero_radix_async(1, streams) };
             let out_block =
                 self.unchecked_is_at_least_one_comparisons_block_true(&blocks_ct, streams);
             return (zero_ct, out_block);