updates to slides3

docs/user/next/slides/slides_3.md

@@ -23,35 +23,33 @@ warnings.filterwarnings('ignore')
 ```{code-cell} ipython3
 import numpy as np
 import gt4py.next as gtx
-from gt4py.next import float64, neighbor_sum, where
-from gt4py.next.common import DimensionKind
-from gt4py.next.program_processors.runners import roundtrip
+from gt4py.next import neighbor_sum, where
 ```
 
 ```{code-cell} ipython3
-CellDim = gtx.Dimension("Cell")
-KDim = gtx.Dimension("K", kind=DimensionKind.VERTICAL)
+Cell = gtx.Dimension("Cell")
+K = gtx.Dimension("K", kind=gtx.DimensionKind.VERTICAL)
 grid_shape = (5, 6)
 ```
 
 ## Using conditionals on fields
 
-To filter operations such that they are performed on only certain cells instead of the whole field, the `where` builtin was developed. 
+To conditionally compose a field from two inputs, we borrow the `where` function from numpy. 
 
 This function takes 3 input arguments:
-- mask: a field of booleans or an expression evaluating to this type
+- mask: a field of booleans
 - true branch: a tuple, a field, or a scalar
 - false branch: a tuple, a field, of a scalar
 
 ```{code-cell} ipython3
-mask = gtx.as_field([CellDim], np.asarray([True, False, True, True, False]))
-result = gtx.as_field([CellDim], np.zeros(shape=grid_shape[0]))
-true_field = gtx.as_field([CellDim], np.asarray([11.0, 12.0, 13.0, 14.0, 15.0]))
-false_field = gtx.as_field([CellDim], np.asarray([21.0, 22.0, 23.0, 24.0, 25.0]))
+mask = gtx.as_field([Cell], np.asarray([True, False, True, True, False]))
+result = gtx.as_field([Cell], np.zeros(shape=grid_shape[0]))
+true_field = gtx.as_field([Cell], np.asarray([11.0, 12.0, 13.0, 14.0, 15.0]))
+false_field = gtx.as_field([Cell], np.asarray([21.0, 22.0, 23.0, 24.0, 25.0]))
 
 @gtx.field_operator
-def conditional(mask: gtx.Field[[CellDim], bool], true_field: gtx.Field[[CellDim], float64], false_field: gtx.Field[[CellDim], float64]
-) -> gtx.Field[[CellDim], float64]:
+def conditional(mask: gtx.Field[[Cell], bool], true_field: gtx.Field[[Cell], gtx.float64], false_field: gtx.Field[[Cell], gtx.float64]
+) -> gtx.Field[[Cell], gtx.float64]:
     return where(mask, true_field, false_field)
 
 conditional(mask, true_field, false_field, out=result, offset_provider={})
@@ -63,27 +61,25 @@ print("where return:      {}".format(result.asnumpy()))
 
 ## Using domain on fields
 
-Another way to filter parts of a field where to perform operations, is to use the `domain` keyword argument when calling the field operator.
-
-Note: domain needs both dimensions to be included with integer tuple values.
+By default the whole `out` field is updated. If only a subset should be updated, we can specify the output domain by passing the `domain` keyword argument when calling the field operator.
 
 ```{code-cell} ipython3
 @gtx.field_operator
-def add(a: gtx.Field[[CellDim, KDim], float64],
-        b: gtx.Field[[CellDim, KDim], float64]) -> gtx.Field[[CellDim, KDim], float64]:
+def add(a: gtx.Field[[Cell, K], gtx.float64],
+        b: gtx.Field[[Cell, K], gtx.float64]) -> gtx.Field[[Cell, K], gtx.float64]:
     return a + b   # 2.0 + 3.0
 
 @gtx.program
-def run_add_domain(a : gtx.Field[[CellDim, KDim], float64],
-            b : gtx.Field[[CellDim, KDim], float64],
-            result : gtx.Field[[CellDim, KDim], float64]):
-    add(a, b, out=result, domain={CellDim: (1, 3), KDim: (1, 4)}) 
+def run_add_domain(a : gtx.Field[[Cell, K], gtx.float64],
+            b : gtx.Field[[Cell, K], gtx.float64],
+            result : gtx.Field[[Cell, K], gtx.float64]):
+    add(a, b, out=result, domain={Cell: (1, 3), K: (1, 4)}) 
 ```
 
 ```{code-cell} ipython3
-a = gtx.as_field([CellDim, KDim], np.full(shape=grid_shape, fill_value=2.0, dtype=np.float64))
-b = gtx.as_field([CellDim, KDim], np.full(shape=grid_shape, fill_value=3.0, dtype=np.float64))
-result = gtx.as_field([CellDim, KDim], np.zeros(shape=grid_shape))
+a = gtx.as_field([Cell, K], np.full(shape=grid_shape, fill_value=2.0, dtype=np.float64))
+b = gtx.as_field([Cell, K], np.full(shape=grid_shape, fill_value=3.0, dtype=np.float64))
+result = gtx.as_field([Cell, K], np.zeros(shape=grid_shape))
 run_add_domain(a, b, result, offset_provider={})
 
 print("result array: \n {}".format(result.asnumpy()))