Allow named units to have a LaTeX representation (WIP) (#1069)

* Allow named units to have a LaTeX representation (WIP)

* Add some LaTeX representations and a test for this

src/amuse/test/suite/core_tests/test_console.py

@@ -242,3 +242,7 @@ def test10(self):
             "], ["+tmp+", "+tmp+"]] au")
         self.assertEqual(str(pi), "3.14 none")
         set_printing_strategy("default")
+
+    def test_latex(self):
+        self.assertEqual(str(units.MSun), "MSun")
+        self.assertEqual(str(units.MSun.latex()), r"M_{\odot}")

src/amuse/units/core.py

@@ -64,6 +64,8 @@ class unit(object):
 
     Units can also be named, by creating a named unit.
     """
+
+    _latex_representation = None
     __array_priority__ = 100
 
     def __mul__(self, other):
@@ -142,6 +144,12 @@ def __ne__(self, other):
     def __hash__(self):
         return self._hash
 
+    def latex(self):
+        if self._latex_representation is not None:
+            return self._latex_representation
+        else:
+            return self.symbol
+
     @late
     def _hash(self):
         return hash(id(self))
@@ -853,15 +861,16 @@ class named_unit(unit):
     >>> (20.0 | (60.0 * si.s)).as_quantity_in(minute)
     quantity<20.0 min>
     """
-    def __init__(self, name, symbol, unit):
+
+    def __init__(self, name, symbol, unit, latex=None):
         self.name = name
         self.symbol = symbol
         self.local_unit = unit
+        self._latex_representation = latex
 
     def __str__(self):
         return self.symbol
 
-
     def reference_string(self):
         return self.to_simple_form().reference_string()
 

src/amuse/units/units.py

@@ -50,9 +50,9 @@
 Mpc = named("mega parsec", "Mpc", 10**6 * parsec)
 Gpc = named("giga parsec", "Gpc", 10**9 * parsec)
 lightyear = named("light year", "ly", 9460730472580.8 * km)
-LSun = named("solar luminosity", "LSun", 3.839e26 * W)
-MSun = named("solar mass", "MSun", 1.98892e30 * kg)
-RSun = named("solar radius", "RSun", 6.955e8 * m)
+LSun = named("solar luminosity", "LSun", 3.839e26 * W, latex=r"L_{\odot}")
+MSun = named("solar mass", "MSun", 1.98892e30 * kg, latex=r"M_{\odot}")
+RSun = named("solar radius", "RSun", 6.955e8 * m, latex=r"R_{\odot}")
 MJupiter = named("jupiter mass", "MJupiter", 1.8987e27 * kg)
 RJupiter = named("jupiter radius", "RJupiter", 71492.0 * km)
 MEarth = named("earth mass", "MEarth", 5.9722e24 * kg)