/**
* @author Amol S. Deshmukh < amolweb at ya hoo dot com >
- * @author Johan Karlsteen - added Intercept
+ * @author Johan Karlsteen - added Intercept and Slope
*/
public final class FunctionEval {
/**
retval[305] = new Sumx2py2();
retval[311] = new Intercept();
+ retval[315] = new Slope();
retval[318] = AggregateFunction.DEVSQ;
package org.apache.poi.ss.formula.functions;
-import org.apache.poi.ss.formula.TwoDEval;
-import org.apache.poi.ss.formula.eval.ErrorEval;
-import org.apache.poi.ss.formula.eval.EvaluationException;
-import org.apache.poi.ss.formula.eval.NumberEval;
-import org.apache.poi.ss.formula.eval.RefEval;
import org.apache.poi.ss.formula.eval.ValueEval;
-import org.apache.poi.ss.formula.functions.LookupUtils.ValueVector;
+import org.apache.poi.ss.formula.functions.LinearRegressionFunction.FUNCTION;
/**
* Implementation of Excel function INTERCEPT()<p/>
*/
public final class Intercept extends Fixed2ArgFunction {
- private static abstract class ValueArray implements ValueVector {
- private final int _size;
- protected ValueArray(int size) {
- _size = size;
- }
-
- public ValueEval getItem(int index) {
- if (index < 0 || index > _size) {
- throw new IllegalArgumentException("Specified index " + index
- + " is outside range (0.." + (_size - 1) + ")");
- }
- return getItemInternal(index);
- }
- protected abstract ValueEval getItemInternal(int index);
-
- public final int getSize() {
- return _size;
- }
- }
-
- private static final class SingleCellValueArray extends ValueArray {
- private final ValueEval _value;
- public SingleCellValueArray(ValueEval value) {
- super(1);
- _value = value;
- }
- @Override
- protected ValueEval getItemInternal(int index) {
- return _value;
- }
- }
-
- private static final class RefValueArray extends ValueArray {
- private final RefEval _ref;
- public RefValueArray(RefEval ref) {
- super(1);
- _ref = ref;
- }
- @Override
- protected ValueEval getItemInternal(int index) {
- return _ref.getInnerValueEval();
- }
- }
-
- private static final class AreaValueArray extends ValueArray {
- private final TwoDEval _ae;
- private final int _width;
-
- public AreaValueArray(TwoDEval ae) {
- super(ae.getWidth() * ae.getHeight());
- _ae = ae;
- _width = ae.getWidth();
- }
- @Override
- protected ValueEval getItemInternal(int index) {
- int rowIx = index / _width;
- int colIx = index % _width;
- return _ae.getValue(rowIx, colIx);
- }
+ private final LinearRegressionFunction func;
+ public Intercept() {
+ func = new LinearRegressionFunction(FUNCTION.INTERCEPT);
}
-
+ @Override
public ValueEval evaluate(int srcRowIndex, int srcColumnIndex,
ValueEval arg0, ValueEval arg1) {
- double result;
- try {
- ValueVector vvX = createValueVector(arg0);
- ValueVector vvY = createValueVector(arg1);
- int size = vvX.getSize();
- if (size == 0 || vvY.getSize() != size) {
- return ErrorEval.NA;
- }
- result = evaluateInternal(vvX, vvY, size);
- } catch (EvaluationException e) {
- return e.getErrorEval();
- }
- if (Double.isNaN(result) || Double.isInfinite(result)) {
- return ErrorEval.NUM_ERROR;
- }
- return new NumberEval(result);
+ return func.evaluate(srcRowIndex, srcColumnIndex, arg0, arg1);
}
-
- private double evaluateInternal(ValueVector x, ValueVector y, int size)
- throws EvaluationException {
+}
- // error handling is as if the x is fully evaluated before y
- ErrorEval firstXerr = null;
- ErrorEval firstYerr = null;
- boolean accumlatedSome = false;
- double result = 0.0;
- // first pass: read in data, compute xbar and ybar
- double sumx = 0.0, sumy = 0.0;
-
- for (int i = 0; i < size; i++) {
- ValueEval vx = x.getItem(i);
- ValueEval vy = y.getItem(i);
- if (vx instanceof ErrorEval) {
- if (firstXerr == null) {
- firstXerr = (ErrorEval) vx;
- continue;
- }
- }
- if (vy instanceof ErrorEval) {
- if (firstYerr == null) {
- firstYerr = (ErrorEval) vy;
- continue;
- }
- }
- // only count pairs if both elements are numbers
- if (vx instanceof NumberEval && vy instanceof NumberEval) {
- accumlatedSome = true;
- NumberEval nx = (NumberEval) vx;
- NumberEval ny = (NumberEval) vy;
- sumx += nx.getNumberValue();
- sumy += ny.getNumberValue();
- } else {
- // all other combinations of value types are silently ignored
- }
- }
- double xbar = sumx / size;
- double ybar = sumy / size;
-
- // second pass: compute summary statistics
- double xxbar = 0.0, xybar = 0.0;
- for (int i = 0; i < size; i++) {
- ValueEval vx = x.getItem(i);
- ValueEval vy = y.getItem(i);
-
- if (vx instanceof ErrorEval) {
- if (firstXerr == null) {
- firstXerr = (ErrorEval) vx;
- continue;
- }
- }
- if (vy instanceof ErrorEval) {
- if (firstYerr == null) {
- firstYerr = (ErrorEval) vy;
- continue;
- }
- }
-
- // only count pairs if both elements are numbers
- if (vx instanceof NumberEval && vy instanceof NumberEval) {
- NumberEval nx = (NumberEval) vx;
- NumberEval ny = (NumberEval) vy;
- xxbar += (nx.getNumberValue() - xbar) * (nx.getNumberValue() - xbar);
- xybar += (nx.getNumberValue() - xbar) * (ny.getNumberValue() - ybar);
- } else {
- // all other combinations of value types are silently ignored
- }
- }
- double beta1 = xybar / xxbar;
- double beta0 = ybar - beta1 * xbar;
-
- if (firstXerr != null) {
- throw new EvaluationException(firstXerr);
- }
- if (firstYerr != null) {
- throw new EvaluationException(firstYerr);
- }
- if (!accumlatedSome) {
- throw new EvaluationException(ErrorEval.DIV_ZERO);
- }
-
- result = beta0;
- return result;
- }
-
- private static ValueVector createValueVector(ValueEval arg) throws EvaluationException {
- if (arg instanceof ErrorEval) {
- throw new EvaluationException((ErrorEval) arg);
- }
- if (arg instanceof TwoDEval) {
- return new AreaValueArray((TwoDEval) arg);
- }
- if (arg instanceof RefEval) {
- return new RefValueArray((RefEval) arg);
- }
- return new SingleCellValueArray(arg);
- }
-}
\ No newline at end of file
--- /dev/null
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ====================================================================
+ */
+
+package org.apache.poi.ss.formula.functions;
+
+import org.apache.poi.ss.formula.TwoDEval;
+import org.apache.poi.ss.formula.eval.ErrorEval;
+import org.apache.poi.ss.formula.eval.EvaluationException;
+import org.apache.poi.ss.formula.eval.NumberEval;
+import org.apache.poi.ss.formula.eval.RefEval;
+import org.apache.poi.ss.formula.eval.ValueEval;
+import org.apache.poi.ss.formula.functions.LookupUtils.ValueVector;
+
+/**
+ * Base class for linear regression functions.
+ *
+ * Calculates the linear regression line that is used to predict y values from x values<br/>
+ * (http://introcs.cs.princeton.edu/java/97data/LinearRegression.java.html)
+ * <b>Syntax</b>:<br/>
+ * <b>INTERCEPT</b>(<b>arrayX</b>, <b>arrayY</b>)<p/>
+ * or
+ * <b>SLOPE</b>(<b>arrayX</b>, <b>arrayY</b>)<p/>
+ *
+ *
+ * @author Johan Karlsteen
+ */
+public final class LinearRegressionFunction extends Fixed2ArgFunction {
+
+ private static abstract class ValueArray implements ValueVector {
+ private final int _size;
+ protected ValueArray(int size) {
+ _size = size;
+ }
+ @Override
+ public ValueEval getItem(int index) {
+ if (index < 0 || index > _size) {
+ throw new IllegalArgumentException("Specified index " + index
+ + " is outside range (0.." + (_size - 1) + ")");
+ }
+ return getItemInternal(index);
+ }
+ protected abstract ValueEval getItemInternal(int index);
+ @Override
+ public final int getSize() {
+ return _size;
+ }
+ }
+
+ private static final class SingleCellValueArray extends ValueArray {
+ private final ValueEval _value;
+ public SingleCellValueArray(ValueEval value) {
+ super(1);
+ _value = value;
+ }
+ @Override
+ protected ValueEval getItemInternal(int index) {
+ return _value;
+ }
+ }
+
+ private static final class RefValueArray extends ValueArray {
+ private final RefEval _ref;
+ public RefValueArray(RefEval ref) {
+ super(1);
+ _ref = ref;
+ }
+ @Override
+ protected ValueEval getItemInternal(int index) {
+ return _ref.getInnerValueEval();
+ }
+ }
+
+ private static final class AreaValueArray extends ValueArray {
+ private final TwoDEval _ae;
+ private final int _width;
+
+ public AreaValueArray(TwoDEval ae) {
+ super(ae.getWidth() * ae.getHeight());
+ _ae = ae;
+ _width = ae.getWidth();
+ }
+ @Override
+ protected ValueEval getItemInternal(int index) {
+ int rowIx = index / _width;
+ int colIx = index % _width;
+ return _ae.getValue(rowIx, colIx);
+ }
+ }
+
+ public enum FUNCTION {INTERCEPT, SLOPE};
+ public FUNCTION function;
+
+ public LinearRegressionFunction(FUNCTION function) {
+ this.function = function;
+ }
+
+ @Override
+ public ValueEval evaluate(int srcRowIndex, int srcColumnIndex,
+ ValueEval arg0, ValueEval arg1) {
+ double result;
+ try {
+ ValueVector vvX = createValueVector(arg0);
+ ValueVector vvY = createValueVector(arg1);
+ int size = vvX.getSize();
+ if (size == 0 || vvY.getSize() != size) {
+ return ErrorEval.NA;
+ }
+ result = evaluateInternal(vvX, vvY, size);
+ } catch (EvaluationException e) {
+ return e.getErrorEval();
+ }
+ if (Double.isNaN(result) || Double.isInfinite(result)) {
+ return ErrorEval.NUM_ERROR;
+ }
+ return new NumberEval(result);
+ }
+
+ private double evaluateInternal(ValueVector x, ValueVector y, int size)
+ throws EvaluationException {
+
+ // error handling is as if the x is fully evaluated before y
+ ErrorEval firstXerr = null;
+ ErrorEval firstYerr = null;
+ boolean accumlatedSome = false;
+ double result = 0.0;
+ // first pass: read in data, compute xbar and ybar
+ double sumx = 0.0, sumy = 0.0;
+
+ for (int i = 0; i < size; i++) {
+ ValueEval vx = x.getItem(i);
+ ValueEval vy = y.getItem(i);
+ if (vx instanceof ErrorEval) {
+ if (firstXerr == null) {
+ firstXerr = (ErrorEval) vx;
+ continue;
+ }
+ }
+ if (vy instanceof ErrorEval) {
+ if (firstYerr == null) {
+ firstYerr = (ErrorEval) vy;
+ continue;
+ }
+ }
+ // only count pairs if both elements are numbers
+ if (vx instanceof NumberEval && vy instanceof NumberEval) {
+ accumlatedSome = true;
+ NumberEval nx = (NumberEval) vx;
+ NumberEval ny = (NumberEval) vy;
+ sumx += nx.getNumberValue();
+ sumy += ny.getNumberValue();
+ } else {
+ // all other combinations of value types are silently ignored
+ }
+ }
+ double xbar = sumx / size;
+ double ybar = sumy / size;
+
+ // second pass: compute summary statistics
+ double xxbar = 0.0, xybar = 0.0;
+ for (int i = 0; i < size; i++) {
+ ValueEval vx = x.getItem(i);
+ ValueEval vy = y.getItem(i);
+
+ if (vx instanceof ErrorEval) {
+ if (firstXerr == null) {
+ firstXerr = (ErrorEval) vx;
+ continue;
+ }
+ }
+ if (vy instanceof ErrorEval) {
+ if (firstYerr == null) {
+ firstYerr = (ErrorEval) vy;
+ continue;
+ }
+ }
+
+ // only count pairs if both elements are numbers
+ if (vx instanceof NumberEval && vy instanceof NumberEval) {
+ NumberEval nx = (NumberEval) vx;
+ NumberEval ny = (NumberEval) vy;
+ xxbar += (nx.getNumberValue() - xbar) * (nx.getNumberValue() - xbar);
+ xybar += (nx.getNumberValue() - xbar) * (ny.getNumberValue() - ybar);
+ } else {
+ // all other combinations of value types are silently ignored
+ }
+ }
+ double beta1 = xybar / xxbar;
+ double beta0 = ybar - beta1 * xbar;
+
+ if (firstXerr != null) {
+ throw new EvaluationException(firstXerr);
+ }
+ if (firstYerr != null) {
+ throw new EvaluationException(firstYerr);
+ }
+ if (!accumlatedSome) {
+ throw new EvaluationException(ErrorEval.DIV_ZERO);
+ }
+
+ if(function == FUNCTION.INTERCEPT) {
+ return beta0;
+ } else {
+ return beta1;
+ }
+ }
+
+ private static ValueVector createValueVector(ValueEval arg) throws EvaluationException {
+ if (arg instanceof ErrorEval) {
+ throw new EvaluationException((ErrorEval) arg);
+ }
+ if (arg instanceof TwoDEval) {
+ return new AreaValueArray((TwoDEval) arg);
+ }
+ if (arg instanceof RefEval) {
+ return new RefValueArray((RefEval) arg);
+ }
+ return new SingleCellValueArray(arg);
+ }
+}
+
--- /dev/null
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ====================================================================
+ */
+
+package org.apache.poi.ss.formula.functions;
+
+import org.apache.poi.ss.formula.eval.ValueEval;
+import org.apache.poi.ss.formula.functions.LinearRegressionFunction.FUNCTION;
+
+/**
+ * Implementation of Excel function SLOPE()<p/>
+ *
+ * Calculates the SLOPE of the linear regression line that is used to predict y values from x values<br/>
+ * (http://introcs.cs.princeton.edu/java/97data/LinearRegression.java.html)
+ * <b>Syntax</b>:<br/>
+ * <b>SLOPE</b>(<b>arrayX</b>, <b>arrayY</b>)<p/>
+ *
+ *
+ * @author Johan Karlsteen
+ */
+public final class Slope extends Fixed2ArgFunction {
+
+ private final LinearRegressionFunction func;
+ public Slope() {
+ func = new LinearRegressionFunction(FUNCTION.SLOPE);
+ }
+
+ @Override
+ public ValueEval evaluate(int srcRowIndex, int srcColumnIndex,
+ ValueEval arg0, ValueEval arg1) {
+ return func.evaluate(srcRowIndex, srcColumnIndex, arg0, arg1);
+ }
+}
+
--- /dev/null
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ====================================================================
+ */
+
+package org.apache.poi.ss.formula.functions;
+
+import junit.framework.TestCase;
+
+import org.apache.poi.ss.formula.eval.ErrorEval;
+import org.apache.poi.ss.formula.eval.NumberEval;
+import org.apache.poi.ss.formula.eval.ValueEval;
+/**
+ * Test for Excel function SLOPE()
+ *
+ * @author Johan Karlsteen
+ */
+public final class TestSlope extends TestCase {
+ private static final Function SLOPE = new Slope();
+
+ private static ValueEval invoke(Function function, ValueEval xArray, ValueEval yArray) {
+ ValueEval[] args = new ValueEval[] { xArray, yArray, };
+ return function.evaluate(args, -1, (short)-1);
+ }
+
+ private void confirm(Function function, ValueEval xArray, ValueEval yArray, double expected) {
+ ValueEval result = invoke(function, xArray, yArray);
+ assertEquals(NumberEval.class, result.getClass());
+ assertEquals(expected, ((NumberEval)result).getNumberValue(), 0);
+ }
+ private void confirmError(Function function, ValueEval xArray, ValueEval yArray, ErrorEval expectedError) {
+ ValueEval result = invoke(function, xArray, yArray);
+ assertEquals(ErrorEval.class, result.getClass());
+ assertEquals(expectedError.getErrorCode(), ((ErrorEval)result).getErrorCode());
+ }
+
+ private void confirmError(ValueEval xArray, ValueEval yArray, ErrorEval expectedError) {
+ confirmError(SLOPE, xArray, yArray, expectedError);
+ }
+
+ public void testBasic() {
+ Double exp = Math.pow(10, 7.5);
+ ValueEval[] xValues = {
+ new NumberEval(3+exp),
+ new NumberEval(4+exp),
+ new NumberEval(2+exp),
+ new NumberEval(5+exp),
+ new NumberEval(4+exp),
+ new NumberEval(7+exp),
+ };
+ ValueEval areaEvalX = createAreaEval(xValues);
+
+ ValueEval[] yValues = {
+ new NumberEval(1),
+ new NumberEval(2),
+ new NumberEval(3),
+ new NumberEval(4),
+ new NumberEval(5),
+ new NumberEval(6),
+ };
+ ValueEval areaEvalY = createAreaEval(yValues);
+ confirm(SLOPE, areaEvalX, areaEvalY, 0.7752808988764045);
+ // Excel 2010 gives 0.775280898876405
+ }
+
+ /**
+ * number of items in array is not limited to 30
+ */
+ public void testLargeArrays() {
+ ValueEval[] xValues = createMockNumberArray(100, 3); // [1,2,0,1,2,0,...,0,1]
+ xValues[0] = new NumberEval(2.0); // Changes first element to 2
+ ValueEval[] yValues = createMockNumberArray(100, 101); // [1,2,3,4,...,99,100]
+
+ confirm(SLOPE, createAreaEval(xValues), createAreaEval(yValues), -1.231527093596059);
+ // Excel 2010 gives -1.23152709359606
+ }
+
+ private ValueEval[] createMockNumberArray(int size, double value) {
+ ValueEval[] result = new ValueEval[size];
+ for (int i = 0; i < result.length; i++) {
+ result[i] = new NumberEval((i+1)%value);
+ }
+ return result;
+ }
+
+ private static ValueEval createAreaEval(ValueEval[] values) {
+ String refStr = "A1:A" + values.length;
+ return EvalFactory.createAreaEval(refStr, values);
+ }
+
+ public void testErrors() {
+ ValueEval[] xValues = {
+ ErrorEval.REF_INVALID,
+ new NumberEval(2),
+ };
+ ValueEval areaEvalX = createAreaEval(xValues);
+ ValueEval[] yValues = {
+ new NumberEval(2),
+ ErrorEval.NULL_INTERSECTION,
+ };
+ ValueEval areaEvalY = createAreaEval(yValues);
+ ValueEval[] zValues = { // wrong size
+ new NumberEval(2),
+ };
+ ValueEval areaEvalZ = createAreaEval(zValues);
+
+ // if either arg is an error, that error propagates
+ confirmError(ErrorEval.REF_INVALID, ErrorEval.NAME_INVALID, ErrorEval.REF_INVALID);
+ confirmError(areaEvalX, ErrorEval.NAME_INVALID, ErrorEval.NAME_INVALID);
+ confirmError(ErrorEval.NAME_INVALID, areaEvalX, ErrorEval.NAME_INVALID);
+
+ // array sizes must match
+ confirmError(areaEvalX, areaEvalZ, ErrorEval.NA);
+ confirmError(areaEvalZ, areaEvalY, ErrorEval.NA);
+
+ // any error in an array item propagates up
+ confirmError(areaEvalX, areaEvalX, ErrorEval.REF_INVALID);
+
+ // search for errors array by array, not pair by pair
+ confirmError(areaEvalX, areaEvalY, ErrorEval.REF_INVALID);
+ confirmError(areaEvalY, areaEvalX, ErrorEval.NULL_INTERSECTION);
+ }
+}
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