fix: node_sample_weight array dtype with xgboost explainer (#52)

* fix: simplify test

* style: whitespaces and EOL

* docs: accepted option name is log_loss now

* fix: node_sample_weights needs to be double

The dtype here needs to match with the dtype declared in the _cext.cc file, which is
NPY_DOUBLE.

* fix: use adult dataset instead

because we need a binary label. Iris dataset is not binary

shap/cext/_cext.cc

@@ -62,7 +62,7 @@ static PyObject *_cext_compute_expectations(PyObject *self, PyObject *args)
     PyObject *children_right_obj;
     PyObject *node_sample_weight_obj;
     PyObject *values_obj;
-    
+
     /* Parse the input tuple */
     if (!PyArg_ParseTuple(
         args, "OOOO", &children_left_obj, &children_right_obj, &node_sample_weight_obj, &values_obj
@@ -131,7 +131,7 @@ static PyObject *_cext_dense_tree_shap(PyObject *self, PyObject *args)
     int model_output;
     PyObject *base_offset_obj;
     bool interactions;
-  
+
     /* Parse the input tuple */
     if (!PyArg_ParseTuple(
         args, "OOOOOOOiOOOOOiOOiib", &children_left_obj, &children_right_obj, &children_default_obj,
@@ -222,7 +222,7 @@ static PyObject *_cext_dense_tree_shap(PyObject *self, PyObject *args)
     // retrieve return value before python cleanup of objects
     tfloat ret_value = (double)values[0];
 
-    // clean up the created python objects 
+    // clean up the created python objects
     Py_XDECREF(children_left_array);
     Py_XDECREF(children_right_array);
     Py_XDECREF(children_default_array);
@@ -261,7 +261,7 @@ static PyObject *_cext_dense_tree_predict(PyObject *self, PyObject *args)
     PyObject *X_missing_obj;
     PyObject *y_obj;
     PyObject *out_pred_obj;
-  
+
     /* Parse the input tuple */
     if (!PyArg_ParseTuple(
         args, "OOOOOOiiOiOOOO", &children_left_obj, &children_right_obj, &children_default_obj,
@@ -339,7 +339,7 @@ static PyObject *_cext_dense_tree_predict(PyObject *self, PyObject *args)
 
     dense_tree_predict(out_pred, trees, data, model_output);
 
-    // clean up the created python objects 
+    // clean up the created python objects
     Py_XDECREF(children_left_array);
     Py_XDECREF(children_right_array);
     Py_XDECREF(children_default_array);
@@ -371,7 +371,7 @@ static PyObject *_cext_dense_tree_update_weights(PyObject *self, PyObject *args)
     PyObject *node_sample_weight_obj;
     PyObject *X_obj;
     PyObject *X_missing_obj;
-  
+
     /* Parse the input tuple */
     if (!PyArg_ParseTuple(
         args, "OOOOOOiOOO", &children_left_obj, &children_right_obj, &children_default_obj,
@@ -433,14 +433,14 @@ static PyObject *_cext_dense_tree_update_weights(PyObject *self, PyObject *args)
 
     dense_tree_update_weights(trees, data);
 
-    // clean up the created python objects 
+    // clean up the created python objects
     Py_XDECREF(children_left_array);
     Py_XDECREF(children_right_array);
     Py_XDECREF(children_default_array);
     Py_XDECREF(features_array);
     Py_XDECREF(thresholds_array);
     Py_XDECREF(values_array);
-    //PyArray_ResolveWritebackIfCopy(node_sample_weight_array);
+    // PyArray_ResolveWritebackIfCopy(node_sample_weight_array);
     Py_XDECREF(node_sample_weight_array);
     Py_XDECREF(X_array);
     Py_XDECREF(X_missing_array);
@@ -467,8 +467,8 @@ static PyObject *_cext_dense_tree_saabas(PyObject *self, PyObject *args)
     PyObject *X_missing_obj;
     PyObject *y_obj;
     PyObject *out_pred_obj;
-    
-  
+
+
     /* Parse the input tuple */
     if (!PyArg_ParseTuple(
         args, "OOOOOOiiOiOOOO", &children_left_obj, &children_right_obj, &children_default_obj,
@@ -540,7 +540,7 @@ static PyObject *_cext_dense_tree_saabas(PyObject *self, PyObject *args)
 
     dense_tree_saabas(out_pred, trees, data);
 
-    // clean up the created python objects 
+    // clean up the created python objects
     Py_XDECREF(children_left_array);
     Py_XDECREF(children_right_array);
     Py_XDECREF(children_default_array);
@@ -557,4 +557,4 @@ static PyObject *_cext_dense_tree_saabas(PyObject *self, PyObject *args)
     /* Build the output tuple */
     PyObject *ret = Py_BuildValue("d", (double)values[0]);
     return ret;
-}
+}