Add implementation of RATE from patch in bug #52050

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1186111 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/src/documentation/content/xdocs/status.xml b/src/documentation/content/xdocs/status.xml
index 97282270b08a356d53af6422033c02f63967ec1a..06bd108fd52450a75711ce9ea8ef66c66d593c34 100644 (file)
--- a/src/documentation/content/xdocs/status.xml
+++ b/src/documentation/content/xdocs/status.xml
@@ -34,6 +34,7 @@
 
     <changes>
         <release version="3.8-beta5" date="2011-??-??">
+           <action dev="poi-developers" type="add">52050 - Support for the Excel RATE function</action>
            <action dev="poi-developers" type="fix">51566 - HSLF fix for finishing parsing the picture stream on the first non-valid type</action>
            <action dev="poi-developers" type="fix">51974 - Avoid HWPF issue when identifying the picture type</action>
            <action dev="poi-developers" type="fix">52035 - Fix signed issue with very large word 6 files</action>

diff --git a/src/java/org/apache/poi/ss/formula/eval/FunctionEval.java b/src/java/org/apache/poi/ss/formula/eval/FunctionEval.java
index 428b6d797dbf15f0618bea28164e56cbd74f93db..b3a18c1a14346cacbe19218c5e0bdf7bf76e2a01 100644 (file)
--- a/src/java/org/apache/poi/ss/formula/eval/FunctionEval.java
+++ b/src/java/org/apache/poi/ss/formula/eval/FunctionEval.java
@@ -102,6 +102,7 @@ public final class FunctionEval {
                retval[58] = FinanceFunction.NPER;
                retval[59] = FinanceFunction.PMT;
 
+      retval[60] = new Rate();
                retval[62] = new Irr();
                retval[63] = NumericFunction.RAND;
                retval[64] = new Match();

diff --git a/src/java/org/apache/poi/ss/formula/functions/Rate.java b/src/java/org/apache/poi/ss/formula/functions/Rate.java
new file mode 100644 (file)
index 0000000..bc53585
--- /dev/null
+++ b/src/java/org/apache/poi/ss/formula/functions/Rate.java
@@ -0,0 +1,119 @@
+/* ====================================================================\r
+   Licensed to the Apache Software Foundation (ASF) under one or more\r
+   contributor license agreements.  See the NOTICE file distributed with\r
+   this work for additional information regarding copyright ownership.\r
+   The ASF licenses this file to You under the Apache License, Version 2.0\r
+   (the "License"); you may not use this file except in compliance with\r
+   the License.  You may obtain a copy of the License at\r
+\r
+       http://www.apache.org/licenses/LICENSE-2.0\r
+\r
+   Unless required by applicable law or agreed to in writing, software\r
+   distributed under the License is distributed on an "AS IS" BASIS,\r
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
+   See the License for the specific language governing permissions and\r
+   limitations under the License.\r
+==================================================================== */\r
+\r
+package org.apache.poi.ss.formula.functions;\r
+\r
+import org.apache.poi.ss.formula.eval.ErrorEval;\r
+import org.apache.poi.ss.formula.eval.EvaluationException;\r
+import org.apache.poi.ss.formula.eval.NumberEval;\r
+import org.apache.poi.ss.formula.eval.OperandResolver;\r
+import org.apache.poi.ss.formula.eval.ValueEval;\r
+\r
+/**\r
+ * Implements the Excel Rate function\r
+ */\r
+public class Rate implements Function {\r
+   public ValueEval evaluate(ValueEval[] args, int srcRowIndex, int srcColumnIndex) {\r
+      if (args.length < 3) { //First 3 parameters are mandatory\r
+         return ErrorEval.VALUE_INVALID;\r
+      }\r
+\r
+      double periods, payment, present_val, future_val = 0, type = 0, estimate = 0.1, rate;\r
+\r
+      try {\r
+         ValueEval v1 = OperandResolver.getSingleValue(args[0], srcRowIndex, srcColumnIndex);\r
+         ValueEval v2 = OperandResolver.getSingleValue(args[1], srcRowIndex, srcColumnIndex);\r
+         ValueEval v3 = OperandResolver.getSingleValue(args[2], srcRowIndex, srcColumnIndex);\r
+         ValueEval v4 = null;\r
+         if (args.length >= 4)\r
+            v4 = OperandResolver.getSingleValue(args[3], srcRowIndex, srcColumnIndex);\r
+         ValueEval v5 = null;\r
+         if (args.length >= 5)\r
+            v5 = OperandResolver.getSingleValue(args[4], srcRowIndex, srcColumnIndex);\r
+         ValueEval v6 = null;\r
+         if (args.length >= 6)\r
+            v6 = OperandResolver.getSingleValue(args[5], srcRowIndex, srcColumnIndex);\r
+\r
+         periods = OperandResolver.coerceValueToDouble(v1); \r
+         payment = OperandResolver.coerceValueToDouble(v2);\r
+         present_val = OperandResolver.coerceValueToDouble(v3);\r
+         if (args.length >= 4)\r
+            future_val = OperandResolver.coerceValueToDouble(v4);\r
+         if (args.length >= 5)\r
+            type = OperandResolver.coerceValueToDouble(v5);\r
+         if (args.length >= 6)\r
+            estimate = OperandResolver.coerceValueToDouble(v6);\r
+         rate = calculateRate(periods, payment, present_val, future_val, type, estimate) ;\r
+\r
+         checkValue(rate);\r
+      } catch (EvaluationException e) {\r
+         e.printStackTrace() ;\r
+         return e.getErrorEval();\r
+      }\r
+\r
+      return new NumberEval( rate ) ;\r
+   }\r
+\r
+   private double calculateRate(double nper, double pmt, double pv, double fv, double type, double guess) {\r
+      //FROM MS http://office.microsoft.com/en-us/excel-help/rate-HP005209232.aspx\r
+      int FINANCIAL_MAX_ITERATIONS = 20;//Bet accuracy with 128\r
+      double FINANCIAL_PRECISION = 0.0000001;//1.0e-8\r
+\r
+      double y, y0, y1, x0, x1 = 0, f = 0, i = 0;\r
+      double rate = guess;\r
+      if (Math.abs(rate) < FINANCIAL_PRECISION) {\r
+         y = pv * (1 + nper * rate) + pmt * (1 + rate * type) * nper + fv;\r
+      } else {\r
+         f = Math.exp(nper * Math.log(1 + rate));\r
+         y = pv * f + pmt * (1 / rate + type) * (f - 1) + fv;\r
+      }\r
+      y0 = pv + pmt * nper + fv;\r
+      y1 = pv * f + pmt * (1 / rate + type) * (f - 1) + fv;\r
+\r
+      // find root by Newton secant method\r
+      i = x0 = 0.0;\r
+      x1 = rate;\r
+      while ((Math.abs(y0 - y1) > FINANCIAL_PRECISION) && (i < FINANCIAL_MAX_ITERATIONS)) {\r
+         rate = (y1 * x0 - y0 * x1) / (y1 - y0);\r
+         x0 = x1;\r
+         x1 = rate;\r
+\r
+         if (Math.abs(rate) < FINANCIAL_PRECISION) {\r
+            y = pv * (1 + nper * rate) + pmt * (1 + rate * type) * nper + fv;\r
+         } else {\r
+            f = Math.exp(nper * Math.log(1 + rate));\r
+            y = pv * f + pmt * (1 / rate + type) * (f - 1) + fv;\r
+         }\r
+\r
+         y0 = y1;\r
+         y1 = y;\r
+         ++i;\r
+      }\r
+      return rate;\r
+   }\r
+\r
+   /**\r
+    * Excel does not support infinities and NaNs, rather, it gives a #NUM! error in these cases\r
+    * \r
+    * @throws EvaluationException (#NUM!) if <tt>result</tt> is <tt>NaN</> or <tt>Infinity</tt>\r
+    */\r
+   static final void checkValue(double result) throws EvaluationException {\r
+      if (Double.isNaN(result) || Double.isInfinite(result)) {\r
+         throw new EvaluationException(ErrorEval.NUM_ERROR);\r
+      }\r
+   }\r
+}\r