Issue 78 - decimals/precision

oblib/data_model.py

@@ -444,14 +444,15 @@ class Fact(object):
     as either XML or JSON. A Fact provides a value for a certain concept within
     a certain context, and can optionally provide units and a precision.
     """
-    def __init__(self, concept, context, unit, value, decimals=2):
+    def __init__(self, concept, context, unit, value, decimals=None, precision=None):
         """
         Concept is the field name - it must match the schema definition.
         Context is a reference to this fact's parent Context object.
         Units is a string naming the unit, for example "kWh"
-        Value is a string, integer, or float
-        Decimals is used only for float types, it is the number of
-        digits
+        Value is a string, integer, or float.
+        For numeric types only, precision OR decimals (not both) can be specified.
+        Decimals is the number of digits past the decimal point; precision is
+        the total number of significant digits.
         """
         # in case of xml the context ID will be rendered in the fact tag.
         # in case of json the contexts' attributes will be copied to the
@@ -460,7 +461,15 @@ def __init__(self, concept, context, unit, value, decimals=2):
         self.value = value
         self.context = context
         self.unit = unit
+
+        if decimals is not None and precision is not None:
+            raise OBException("Fact given both precision and decimals - use only one.")
         self.decimals = decimals
+        self.precision = precision
+        if decimals is None and precision is None:
+            # Default to 2 decimals:
+            self.decimals = 2
+
         # Fill in the id property with a UUID:
         self.id = identifier.identifier() # Only used when exporting JSON
 
@@ -473,10 +482,13 @@ def _toXML(self):
         # also the self.unit may not be correct unitRef? not sure
         if self.unit is not None:
             attribs["unitRef"] = self.unit
-            if self.unit == "pure" or self.unit == "degrees":
+            if self.unit == "pure":
                 attribs["decimals"] = "0"
             else:
-                attribs["decimals"] = str(self.decimals)
+                if self.decimals is not None:
+                    attribs["decimals"] = str(self.decimals)
+                elif self.precision is not None:
+                    attribs["precision"] = str(self.precision)
         elem = Element(self.concept, attrib=attribs)
         if self.unit == "pure":
             elem.text = "%d" % self.value
@@ -493,6 +505,13 @@ def _toJSON(self):
         aspects["concept"] = self.concept
         if self.unit is not None:
             aspects["unit"] = self.unit
+            if self.unit == "pure":
+                aspects["decimals"] = "0"
+            else:
+                if self.decimals is not None:
+                    aspects["decimals"] = str(self.decimals)
+                elif self.precision is not None:
+                    aspects["precision"] = str(self.precision)
 
         if isinstance( self.value, datetime.datetime):
             value_str = self.value.strftime("%Y-%m-%dT%H:%M:%S")
@@ -986,6 +1005,12 @@ def set(self, concept_name, value, **kwargs):
 
         if "precision" in kwargs:
             precision = kwargs.pop("precision")
+        else:
+            precision = None
+        if "decimals" in kwargs:
+            decimals = kwargs.pop("decimals")
+        else:
+            decimals = None
 
         if not self.is_concept_writable(concept_name):
             raise OBConceptException(
@@ -1027,8 +1052,9 @@ def set(self, concept_name, value, **kwargs):
         table = self.get_table_for_concept(concept_name)
         context = table.store_context(context) # dedupes, assigns ID
 
-        f = Fact(concept_name, context, unit_name, value)
-        # TODO pass in decimals? Fact expects decimals and "precision" is slightly different
+        f = Fact(concept_name, context, unit_name, value,
+                 precision=precision,
+                 decimals=decimals)
 
         # self.facts is nested dict keyed first on table then on context ID
         # and finally on concept:

oblib/tests/test_data_model.py

@@ -14,6 +14,7 @@
 
 import unittest
 from data_model import OBInstance, Context, Hypercube, UNTABLE
+from data_model import OBException, OBContextException
 from datetime import datetime, date
 from taxonomy import getTaxonomy
 from lxml import etree
@@ -648,7 +649,7 @@ def test_hypercube_rejects_context_with_unwanted_axes(self):
             instant = datetime.now())
         # InverterPowerLevelPercentAxis is a valid axis and this is a valid value for it,
         # but the table that holds DeviceCost doesn't want this axis:
-        with self.assertRaises(Exception):
+        with self.assertRaises(OBContextException):
             doc.validate_context("solar:DeviceCost", threeAxisContext)
 
 
@@ -774,4 +775,43 @@ def test_validate_values_for_enumerated_solar_data_types(self):
         pass
 
 
+    def test_decimals_and_precision(self):
+        # if we set a fact and pass in a Decimals argument,
+        # then when we write out to JSON or XML we should see decimals there.
+        # Same with Precision.
+        # Trying to set both Decimals and Precision should give an error.
+        # If we don't set either, it should default to decimals=2.
+
+        doc = OBInstance("CutSheet", self.taxonomy)
+        now = datetime.now()
+        doc.set_default_context({"entity": "JUPITER",
+                               "solar:TestConditionAxis": "solar:StandardTestConditionMember",
+                               PeriodType.instant: now,
+                               PeriodType.duration: "forever"
+                               })
 
+        # If we set a fact that wants a duration context, it should use jan 1 - jan 31:
+        doc.set("solar:ModuleNameplateCapacity", "6.25", unit_name="W",
+                ProductIdentifierAxis = 1, precision = 3)
+
+        jsonstring = doc.to_JSON_string()
+        facts = json.loads(jsonstring)["facts"]
+
+        # TODO is supposed to be in aspects or not?
+        self.assertEqual(len(facts), 1)
+        self.assertEqual(facts.values()[0]["aspects"]["precision"], "3")
+
+        doc.set("solar:ModuleNameplateCapacity", "6.25", unit_name="W",
+                ProductIdentifierAxis = 1, decimals = 3)
+        jsonstring = doc.to_JSON_string()
+        facts = json.loads(jsonstring)["facts"]
+        self.assertEqual(len(facts), 1)
+        self.assertEqual(facts.values()[0]["aspects"]["decimals"], "3")
+
+        # Trying to set both decimals and precision should raise an error
+        with self.assertRaises(OBException):
+            doc.set("solar:ModuleNameplateCapacity", "6.25", unit_name="W",
+                ProductIdentifierAxis = 1, decimals = 3, precision=3)
+
+
+

requirements.txt

@@ -16,6 +16,3 @@ Sphinx==1.8.2
 sphinx-rtd-theme==0.4.2
 sphinxcontrib-websupport==1.1.0
 
-# pyinstaller
-pyinstaller==3.4
-