update to precision; new default is None so no round is performed.

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = unitpy
-version = 0.0.18
+version = 0.0.19
 description = Working with scientific units in python.
 long_description = file: README.md
 long_description_content_type = text/markdown

src/unitpy/__init__.py

@@ -1,5 +1,6 @@
 import pkg_resources
 
+from unitpy.config import CONFIG
 import unitpy.errors as errors
 from unitpy.definitions.ledger import ledger
 from unitpy.core import Unit, Quantity

src/unitpy/config.py

@@ -52,7 +52,9 @@ class StringFormat(enum.Enum):
         # latex = 2
         # html = 3
 
-    def __init__(self):
+    def __init__(self, precision: int | None = None):
+        """"""
+        self.precision = precision
         self.format_symbols = Config.StringFormat.symbols
         self.integer_format_numerator_parenthesis = False
         self.integer_format_denominator_parenthesis = True
@@ -76,4 +78,4 @@ def get_config_from_env(self):
                 setattr(self, k, v)
 
 
-config = Config()
+CONFIG = Config()

src/unitpy/core.py

@@ -7,15 +7,13 @@
 from datetime import timedelta
 
 from unitpy.errors import UnitDimensionError
-from unitpy.config import config
+from unitpy.config import CONFIG
 from unitpy.definitions.dimensions import Dimension
 from unitpy.definitions.unit_base import BaseSet
 from unitpy.definitions.entry import Entry
 from unitpy.definitions.ledger import ledger
 from unitpy.utils.equation_formating import equation_formater
 
-_precision = 10
-
 
 def get_base_unit(unit: dict[Entry, int | float]) -> BaseSet:
     base = BaseSet()
@@ -89,7 +87,7 @@ def __init__(self, unit: str | dict[Entry, int | float] | BaseSet = None):
         self._offset: int | float | None = None
 
     def __str__(self):
-        if config.abbr:
+        if CONFIG.abbr:
             return self.abbr
         return self.label
 
@@ -552,7 +550,8 @@ def v(self) -> int | float:
     def value(self) -> int | float:
         value = self._value
         if isinstance(value, float):
-            value = round(value, _precision)
+            if CONFIG.precision is not None:
+                value = round(value, CONFIG.precision)
             if value.is_integer():
                 value = int(value)
 
@@ -570,7 +569,8 @@ def unit(self) -> Unit:
     def base_value(self) -> int | float:
         value = self._base_value
         if isinstance(value, float):
-            value = round(value, _precision)
+            if CONFIG.precision is not None:
+                value = round(value, CONFIG.precision)
             if value.is_integer():
                 value = int(value)
 

src/unitpy/utils/equation_formating.py

@@ -1,21 +1,21 @@
 from __future__ import annotations
 
-from unitpy.config import config
+from unitpy.config import CONFIG
 
 
 def equation_formater(dict_: dict[str, int | float]) -> str:
-    if config.format_symbols == config.StringFormat.symbols:
+    if CONFIG.format_symbols == CONFIG.StringFormat.symbols:
         string = format_with_symbols(dict_)
-    elif config.format_symbols == config.StringFormat.power:
+    elif CONFIG.format_symbols == CONFIG.StringFormat.power:
         string = format_with_power(dict_)
     else:
-        raise ValueError("Invalid value for 'config.format_symbols'.")
+        raise ValueError("Invalid value for 'CONFIG.format_symbols'.")
 
     return string
 
 
 def format_with_power(dict_: dict[str, int | float]) -> str:
-    return config.multiplication_seperator.join([f"{k}**{v}" for k, v in dict_.items() if v != 0])
+    return CONFIG.multiplication_seperator.join([f"{k}**{v}" for k, v in dict_.items() if v != 0])
 
 
 def format_with_symbols(dict_: dict) -> str:
@@ -33,15 +33,15 @@ def format_with_symbols(dict_: dict) -> str:
         return format_with_power(dict_)
 
     if denominator:
-        string += config.division_seperator + format_integer_denominator(denominator)
+        string += CONFIG.division_seperator + format_integer_denominator(denominator)
 
     return string
 
 
 def format_integer_numerator(numerator) -> str:
-    string = config.multiplication_seperator.join(format_term(k, power) for k, power in numerator if power != 0)
+    string = CONFIG.multiplication_seperator.join(format_term(k, power) for k, power in numerator if power != 0)
 
-    if config.integer_format_numerator_parenthesis and len(numerator) > 1:
+    if CONFIG.integer_format_numerator_parenthesis and len(numerator) > 1:
         string = "(" + string + ")"
 
     if string == "":
@@ -51,10 +51,10 @@ def format_integer_numerator(numerator) -> str:
 
 
 def format_integer_denominator(denominator) -> str:
-    string = config.multiplication_seperator.join(format_term(k, -1 * power) for k, power in denominator if
-                                                        power != 0)
+    string = CONFIG.multiplication_seperator.join(format_term(k, -1 * power) for k, power in denominator if
+                                                  power != 0)
 
-    if config.integer_format_denominator_parenthesis and len(denominator) > 1:
+    if CONFIG.integer_format_denominator_parenthesis and len(denominator) > 1:
         string = "(" + string + ")"
 
     return string

tests/test_define_quantity.py

@@ -1,7 +1,7 @@
 
 import pytest
 
-from unitpy import U, Q
+from unitpy import U, Q, CONFIG
 
 
 def test_quantity_unit():
@@ -60,3 +60,19 @@ def test_format_str4():
     q = Q("100 km/h")
     string = f"{q:4}"
     assert string == " 100 kilometer/hour"
+
+
+def test_precision():
+    wl0 = Q(630, "nm")
+    dwl = Q(20, "pm")
+    wl1 = wl0 + dwl
+    assert wl1 != wl0
+
+
+def test_precision2():
+    CONFIG.precision = 9
+    wl0 = Q(630, "nm")
+    dwl = Q(20, "pm")
+    wl1 = wl0 + dwl
+    assert wl1 == wl0
+    CONFIG.precision = None

tests/test_quanitiy_math_operations.py

@@ -95,7 +95,7 @@ def test_compare_e():
 
 
 def test_compare_e2():
-    assert (Q("1 ft") == Q("12 in")) is True
+    assert Q("1 ft").is_close(Q("12 in")) is True
 
 
 def test_compare_error_gt():