feat: read bed stress data

src/Fvcom.fs

@@ -99,6 +99,16 @@ let readUV (ds: DataSet) t l =
         Log.Error $"{e}"
         Array.empty
 
+let readBedStress (ds: DataSet) t =
+    try
+        let n = ds.Dimensions["nele"].Length
+        let tau = ds[ "tauc" ].GetData([| t; 0 |], [| 1; n |]) :?> single [,]
+        tau[0, *]
+    with
+    | e ->
+        Log.Error $"{e}"
+        Array.empty
+
 let readUV' (ds: DataSet) t l =
     readUV ds t l
     |> Array.collect (fun (x, y) -> [| x; y |])