decode_uvfits_baseline() calculation fixed. Fixes #36

Author: gsleap

src/io/uvfits.rs

@@ -80,7 +80,7 @@ pub const fn encode_uvfits_baseline(ant1: usize, ant2: usize) -> usize {
 /// start at 1.
 #[allow(dead_code)]
 pub const fn decode_uvfits_baseline(bl: usize) -> (usize, usize) {
-    if bl < 65_535 {
+    if bl <= 65_535 {
         let ant2 = bl % 256;
         let ant1 = (bl - ant2) / 256;
         (ant1, ant2)
@@ -2830,4 +2830,110 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn test_encode_uvfits_baseline_256t() {
+        // test hand calculated edge cases
+        assert_eq!(encode_uvfits_baseline(1,1), 257);
+        assert_eq!(encode_uvfits_baseline(1,2), 258);
+        assert_eq!(encode_uvfits_baseline(1,255), 511);
+        assert_eq!(encode_uvfits_baseline(1,256), 67840);
+        assert_eq!(encode_uvfits_baseline(127,127), 32639);
+        assert_eq!(encode_uvfits_baseline(127,255), 32767);
+        assert_eq!(encode_uvfits_baseline(127,256), 325888);
+        assert_eq!(encode_uvfits_baseline(128,128), 32896);
+        assert_eq!(encode_uvfits_baseline(128,255), 33023);
+        assert_eq!(encode_uvfits_baseline(128,256), 327936);
+        assert_eq!(encode_uvfits_baseline(254,254), 65278);
+        assert_eq!(encode_uvfits_baseline(254,255), 65279);
+        assert_eq!(encode_uvfits_baseline(254,256), 585984);
+        assert_eq!(encode_uvfits_baseline(255,255), 65535);
+        assert_eq!(encode_uvfits_baseline(255,256), 588032);
+        assert_eq!(encode_uvfits_baseline(256,256), 590080);
+    }
+
+    #[test]
+    fn test_decode_uvfits_baseline_256t() {
+        // Test hand calculated edge cases
+        assert_eq!(decode_uvfits_baseline(257), (1,1));
+        assert_eq!(decode_uvfits_baseline(258), (1,2));
+        assert_eq!(decode_uvfits_baseline(511), (1,255));
+        assert_eq!(decode_uvfits_baseline(67840), (1,256));
+        assert_eq!(decode_uvfits_baseline(32639), (127,127));
+        assert_eq!(decode_uvfits_baseline(32767), (127,255));
+        assert_eq!(decode_uvfits_baseline(325888), (127,256));
+        assert_eq!(decode_uvfits_baseline(32896), (128,128));
+        assert_eq!(decode_uvfits_baseline(33023), (128,255));
+        assert_eq!(decode_uvfits_baseline(327936), (128,256));
+        assert_eq!(decode_uvfits_baseline(65278), (254,254));
+        assert_eq!(decode_uvfits_baseline(65279), (254,255));
+        assert_eq!(decode_uvfits_baseline(585984), (254,256));
+        assert_eq!(decode_uvfits_baseline(65535), (255,255));
+        assert_eq!(decode_uvfits_baseline(588032), (255,256));
+        assert_eq!(decode_uvfits_baseline(590080), (256,256));
+    }
 }
+
+#[test]
+fn test_encode_decode_uvfits_all_baselines_128t() {
+    // Test all baselines can be encoded then decoded correctly    
+    // MWAX 128T
+    let n_ants: usize= 128;
+    
+    for ant1 in 1..=n_ants {
+        for ant2 in ant1..=n_ants {
+            let bl = encode_uvfits_baseline(ant1, ant2);
+            let (a1,a2) = decode_uvfits_baseline(bl);
+            assert_eq!(a1, ant1);
+            assert_eq!(a2, ant2);
+        }
+    }
+}
+
+#[test]
+fn test_encode_decode_uvfits_all_baselines_256t() {
+    // Test all baselines can be encoded then decoded correctly
+    // MWAX 256T
+    let n_ants: usize= 256;
+    
+    for ant1 in 1..=n_ants {
+        for ant2 in ant1..=n_ants {
+            let bl = encode_uvfits_baseline(ant1, ant2);
+            let (a1,a2) = decode_uvfits_baseline(bl);
+            assert_eq!(a1, ant1);
+            assert_eq!(a2, ant2);
+        }
+    }
+}
+
+#[test]
+fn test_encode_decode_uvfits_all_baselines_264t() {
+    // Test all baselines can be encoded then decoded correctly
+    // MWAX 256T + 1 more receiver
+    let n_ants: usize= 264;
+    
+    for ant1 in 1..=n_ants {
+        for ant2 in ant1..=n_ants {
+            let bl = encode_uvfits_baseline(ant1, ant2);
+            let (a1,a2) = decode_uvfits_baseline(bl);
+            assert_eq!(a1, ant1);
+            assert_eq!(a2, ant2);
+        }
+    }
+}
+
+#[test]
+fn test_encode_decode_uvfits_all_baselines_512t() {
+    // Test all baselines can be encoded then decoded correctly
+    // MWAX 512T (Phase 4(!))
+    let n_ants: usize= 512;
+    
+    for ant1 in 1..=n_ants {
+        for ant2 in ant1..=n_ants {
+            let bl = encode_uvfits_baseline(ant1, ant2);
+            let (a1,a2) = decode_uvfits_baseline(bl);
+            assert_eq!(a1, ant1);
+            assert_eq!(a2, ant2);
+        }
+    }
+}