Add VTKm Probe filter for regular grid resampling (#1247)

* Provide an uniform grid sampling of an in input mesh

src/docs/sphinx/Actions/Examples.rst

@@ -766,6 +766,84 @@ Resulting image:
 
 .. image:: examples/tout_cell_gradient_mag_radial100.png
 
+
+An example of using the  uniform sample grid filter on a 20x20x20 hexahedron mesh to sample a grid that is smaller in each dimension by 10.
+---------------------------------------------------------------------------------------------------------------------
+
+YAML actions:
+
+.. literalinclude:: examples/tout_uniform_smaller_by10_grid100.yaml
+
+Resulting image:
+
+.. image:: examples/tout_uniform_smaller_by10_grid100.png
+
+An example of using the  uniform sample grid filter on a 20x20x20 hexahedron mesh to sample a grid that is equal in dimensions.
+---------------------------------------------------------------------------------------------------------------------
+
+YAML actions:
+
+.. literalinclude:: examples/tout_uniform_equal_grid100.yaml
+
+Resulting image:
+
+.. image:: examples/tout_uniform_equal_grid100.png
+
+An example of using the uniform sample grid filter on a 20x20x20 hexahedron mesh to sample a grid that is equal in dimensions but with smaller spacing between points.
+---------------------------------------------------------------------------------------------------------------------
+
+YAML actions:
+
+.. literalinclude:: examples/tout_uniform_grid_equal_dims_decrease_spacing100.yaml
+
+Resulting image:
+
+.. image:: examples/tout_uniform_grid_equal_dims_decrease_spacing100.png
+
+An example of using the uniform sample grid filter on a 20x20x20 hexahedron mesh to sample a grid that is equal in dimensions but with larger spacing between points.
+---------------------------------------------------------------------------------------------------------------------
+
+YAML actions:
+
+.. literalinclude:: examples/tout_uniform_grid_equal_dims_increase_spacing100.yaml
+
+Resulting image:
+
+.. image:: examples/tout_uniform_grid_equal_dims_increase_spacing100.png
+
+An example of using the uniform sample grid filter on a 20x20x20 hexahedron mesh to sample a grid that is equal in dimensions but with a shifted origin.
+---------------------------------------------------------------------------------------------------------------------
+
+YAML actions:
+
+.. literalinclude:: examples/tout_uniform_grid_shift_origin100.yaml
+
+Resulting image:
+
+.. image:: examples/tout_uniform_grid_shift_origin100.png
+
+An example of using the uniform sample grid filter on a 20x20x20 hexahedron mesh to sample a grid that has larger dimensions by 5.
+---------------------------------------------------------------------------------------------------------------------
+
+YAML actions:
+
+.. literalinclude:: examples/tout_uniform_larger_by5_grid100.yaml
+
+Resulting image:
+
+.. image:: examples/tout_uniform_larger_by5_grid100.png
+
+An example of using the uniform sample grid filter on a 20x20x20 hexahedron mesh to sample a grid that has larger dimensions by 5 and with a disproportionately large invalid_value.
+---------------------------------------------------------------------------------------------------------------------
+
+YAML actions:
+
+.. literalinclude:: examples/tout_uniform_larger_by5_grid_with_invalid_value100.yaml
+
+Resulting image:
+
+.. image:: examples/tout_uniform_larger_by5_grid_with_invalid_value100.png
+
 An example of using the streamline filter and associated tube parameters to produce a rendering.
 --------------------------------------------------------------------------------------------------
 
@@ -778,6 +856,7 @@ Resulting image:
 .. image:: examples/tout_streamline_render100.png
 
 
+
 An example of using the xray extract.
 --------------------------------------
 

src/docs/sphinx/Actions/Pipelines.rst

@@ -878,6 +878,31 @@ the data set has more than one domain. Without ghost, the averaging will not be
   params["association"] = "vertex";   // output field association
   // or params["association"] = "element";   // output field association
 
+Uniform Grid
+~~~~~~~~~~~~~~~~~~~~~
+Uniform Grid filter changes the coordinate system of the input mesh to that of the user-specified regular mesh. Input fields are transferred by sampling the data at the vertex locations of the output geometry. For the output geometry, users must specify the field (`field`) to be sampled, and have the option to specify the origin (`origin`), the number of points along each axis (`dims`) from the origin, and the spacing between these points (`spacing`). 
+
+For distributed data, the final output of this filter is composited on the root process, and ties for sampled points are handled by taking the average of all valid values.
+.. code-block:: c++
+
+  conduit::Node pipelines;
+  // pipeline 1
+  pipelines["pl1/f1/type"] = "sample_grid";
+  //params optional
+  conduit::Node &params = pipelines["pl1/f1/params"];
+  params["field"] = "dist";   //required
+  params["origin/x"] = 0.0;   //default: minimum point in x dim
+  params["origin/y"] = 0.0;   //default: minimum point in y dim
+  params["origin/z"] = 0.0;   //default: minimum point in z dim
+  params["dims/i"] = 10.0;    //default: x extents
+  params["dims/j"] = 10.0;    //default: y extents
+  params["dims/k"] = 10.0;    //default: z extents
+  params["spacing/dx"] = 1.0; //default: 1.0
+  params["spacing/dy"] = 1.0; //default: 1.0
+  params["spacing/dz"] = 1.0; //default: 1.0
+  //field value for sampled points outside of input mesh
+  params["invalid_value"] = -100.0; //default: 0.0
+
 Gradient
 ~~~~~~~~
 Computes the gradient of a vertex-centered input field for every element

src/docs/sphinx/Actions/examples/tout_uniform_equal_grid100.yaml

@@ -0,0 +1,24 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+        params: 
+          dims: 
+            i: 20
+            j: 20
+            k: 20
+          invalid_value: -10.0
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_equal_grid"

src/docs/sphinx/Actions/examples/tout_uniform_grid_default_values100.yaml

@@ -0,0 +1,18 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_grid_default_values"

src/docs/sphinx/Actions/examples/tout_uniform_grid_equal_dims_decrease_spacing100.yaml

@@ -0,0 +1,24 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+        params: 
+          spacing: 
+            dx: 0.5
+            dy: 0.5
+            dz: 0.5
+          invalid_value: -10.0
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_grid_equal_dims_decrease_spacing"

src/docs/sphinx/Actions/examples/tout_uniform_grid_equal_dims_increase_spacing100.yaml

@@ -0,0 +1,35 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+        params: 
+          spacing: 
+            dx: 2.0
+            dy: 2.0
+            dz: 2.0
+          invalid_value: -10.0
+      f2: 
+        type: "slice"
+        params: 
+          point: 
+            x: 0.0
+            y: 0.0
+            z: 0.0
+          normal: 
+            x: 0.0
+            y: 0.0
+            z: 1.0
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_grid_equal_dims_increase_spacing"

src/docs/sphinx/Actions/examples/tout_uniform_grid_shift_origin100.yaml

@@ -0,0 +1,35 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+        params: 
+          origin: 
+            x: -5.0
+            y: -5.0
+            z: -5.0
+          invalid_value: -10.0
+      f2: 
+        type: "slice"
+        params: 
+          point: 
+            x: 0.0
+            y: 0.0
+            z: 0.0
+          normal: 
+            x: 0.0
+            y: 0.0
+            z: 1.0
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_grid_shift_origin"

src/docs/sphinx/Actions/examples/tout_uniform_grid_shift_origin_x100.yaml

@@ -0,0 +1,33 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+        params: 
+          origin: 
+            x: 0.0
+          invalid_value: -10.0
+      f2: 
+        type: "slice"
+        params: 
+          point: 
+            x: 0.0
+            y: 0.0
+            z: 0.0
+          normal: 
+            x: 0.0
+            y: 0.0
+            z: 1.0
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_grid_shift_origin_x"

src/docs/sphinx/Actions/examples/tout_uniform_grid_shift_origin_y100.yaml

@@ -0,0 +1,33 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+        params: 
+          origin: 
+            y: 0.0
+          invalid_value: -10.0
+      f2: 
+        type: "slice"
+        params: 
+          point: 
+            x: 0.0
+            y: 0.0
+            z: 0.0
+          normal: 
+            x: 0.0
+            y: 0.0
+            z: 1.0
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_grid_shift_origin_y"

src/docs/sphinx/Actions/examples/tout_uniform_grid_shift_origin_z100.yaml

@@ -0,0 +1,33 @@
+#An example of using the uniform grid filter.
+
+- 
+  action: "add_pipelines"
+  pipelines: 
+    pl1: 
+      f1: 
+        type: "uniform_grid"
+        params: 
+          origin: 
+            z: 0.0
+          invalid_value: -10.0
+      f2: 
+        type: "slice"
+        params: 
+          point: 
+            x: 0.0
+            y: 0.0
+            z: 0.0
+          normal: 
+            x: 0.0
+            y: 0.0
+            z: 1.0
+- 
+  action: "add_scenes"
+  scenes: 
+    s1: 
+      plots: 
+        p1: 
+          type: "pseudocolor"
+          field: "braid"
+          pipeline: "pl1"
+      image_prefix: "/home/user/ascent/build/tests/_output/tout_uniform_grid_shift_origin_z"