for some reason computing the mean in python and netcdfc++ gives two slightly different values

src/main.cu

@@ -7,16 +7,22 @@
 
 int main() {
     std::string path = "data/MERRA2_400.inst6_3d_ana_Np.20120101.nc4";
-    std::string variable = "U";
+    std::string variable = "T";
     auto x = readData(path, variable);
 
     // Print some values from the file to see that it worked
-    int num = 0;
+    float sum = 0;
+    int n = 0;
+    int skipped = 0;
     for(int i = 0; i < x.size(); i++) {
-        if (x[i] < 1E14) std::cout << x[i] << "\n";
-        if(num > 10000) break;
-        num++;
+        if (x[i] < 1E14) {
+            sum += x[i];
+            n++;
+        } else {
+            skipped++;
+        }
     }
+    std::cout << "Mean = " << sum/n << " and sum = " << sum << " using " << n << " values in computation and skipped " << skipped << " values.\n";
 
     return 0;
 }

test_read.py

@@ -15,9 +15,18 @@ print("Shape of U:", U.shape)
 
 # Compute the mean of the variable across all axes (for all elements in U)
 U_mean = np.mean(U)
+U_sum = np.sum(U)
 
 # Print the mean
 print("Mean of U:", U_mean)
 
+print("Sum of U:", U_sum)
+
+masked_count = np.ma.count_masked(U)
+print("Number of masked values in U:", masked_count)
+
+nan_count = np.isnan(U).sum()
+print("Number of NaN values in U:", nan_count)
+
 # Close the NetCDF file
 ncfile.close()