Bug found calculating the exact mass given a molecular formula when i…

…t is negative charged. Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
egonw · Jul 21, 2009 · 3d1de45 · 3d1de45
1 parent 73225a0
commit 3d1de45
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Showing 2 changed files with 16 additions and 1 deletion.
diff --git a/src/main/org/openscience/cdk/tools/manipulator/MolecularFormulaManipulator.java b/src/main/org/openscience/cdk/tools/manipulator/MolecularFormulaManipulator.java
@@ -586,7 +586,7 @@ private static double correctMass(double mass, Integer charge) {
 		  if(charge > 0)
 			mass -= massE*charge;
 		 else if(charge < 0)
-			mass += massE*charge; 
+			mass += massE*Math.abs(charge); 
 		 return mass;
 	}
 

diff --git a/src/test/org/openscience/cdk/tools/manipulator/MolecularFormulaManipulatorTest.java b/src/test/org/openscience/cdk/tools/manipulator/MolecularFormulaManipulatorTest.java
@@ -397,6 +397,21 @@ public void testGetTotalExactMassWithCharge_IMolecularFormula() throws Exception
         formula.setCharge(1);
     	double totalExactMass2 = MolecularFormulaManipulator.getTotalExactMass(formula);
         Assert.assertEquals(33.03349,totalExactMass2,0.0001);
+    }
+	/**
+     * A unit test suite for JUnit. Test total Exact Mass.
+     *
+     * @throws IOException
+     * @throws ClassNotFoundException
+     * @throws CDKException
+     */
+    @Test 
+    public void testGetTotalExactMassWithChargeNeg_IMolecularFormula() throws IOException, ClassNotFoundException, CDKException{
+
+		IMolecularFormula formula = MolecularFormulaManipulator.getMajorIsotopeMolecularFormula("H2PO4", builder);
+        formula.setCharge(-1);
+    	double totalExactMass2 = MolecularFormulaManipulator.getTotalExactMass(formula);
+        Assert.assertEquals(96.96961875390926,totalExactMass2,0.0001);
     }
     @Test 
     public void testGetNaturalExactMass_IMolecularFormula() throws Exception {