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Changed rounding to use BigDecimals to avoid noisy long doubles in output

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This commit is contained in:
Wouter Lagerweij 2017-09-17 14:27:49 +02:00
parent aaa3f648d0
commit 02c2213545
2 changed files with 22 additions and 33 deletions
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52
app/src/main/java/info/nightscout/utils/Round.java
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@ -7,43 +7,31 @@ import java.math.BigDecimal;
*/ */
public class Round { public class Round {
public static Double roundTo(Double x, Double step) { public static Double roundTo(Double x, Double step) {
return round(x, step, BigDecimal.ROUND_HALF_UP);
if (step > 1) {
return roundToWhole(x, step);
} else {
return roundToNrOfDecimals(x, getDecimalsFromStep(step));
} }
public static Double floorTo(Double x, Double step) {
return round(x, step, BigDecimal.ROUND_FLOOR);
}
public static Double ceilTo(Double x, Double step) {
return round(x, step, BigDecimal.ROUND_CEILING);
}
private static Double round(Double x, Double step, int roundingMode) {
BigDecimal numberToRound = new BigDecimal((Double.toString(x)));
BigDecimal stepSize = new BigDecimal((Double.toString(step)));
int scale = getDecimalsFromStep(step);
numberToRound.setScale(scale, BigDecimal.ROUND_HALF_UP);
BigDecimal rounded = numberToRound.divide(stepSize, 0, roundingMode).multiply(stepSize);
return rounded.doubleValue();
} }
private static int getDecimalsFromStep(Double step) { private static int getDecimalsFromStep(Double step) {
String stepString = Double.toString(step); String stepString = Double.toString(step);
return stepString.substring(stepString.indexOf('.') + 1).length(); return stepString.substring(stepString.indexOf('.') + 1).length();
} }
private static Double roundToNrOfDecimals(Double x, int decimals) {
BigDecimal number = new BigDecimal(Double.toString(x));
number = number.setScale(decimals, BigDecimal.ROUND_HALF_UP);
return number.doubleValue();
}
private static Double roundToWhole(Double x, Double step) {
if (x != 0d) {
return Math.round(x / step) * step;
}
return 0d;
}
public static Double floorTo(Double x, Double step) {
if (x != 0d) {
return Math.floor(x / step) * step;
}
return 0d;
}
public static Double ceilTo(Double x, Double step) {
if (x != 0d) {
return Math.ceil(x / step) * step;
}
return 0d;
}
} }

3
app/src/test/java/info/nightscout/utils/RoundTest.java
View file

@ -14,6 +14,8 @@ public class RoundTest {
public void roundToTest() throws Exception { public void roundToTest() throws Exception {
assertEquals( 0.55d, Round.roundTo(0.54d, 0.05d), 0.00000001d ); assertEquals( 0.55d, Round.roundTo(0.54d, 0.05d), 0.00000001d );
assertEquals( 1d, Round.roundTo(1.49d, 1d), 0.00000001d ); assertEquals( 1d, Round.roundTo(1.49d, 1d), 0.00000001d );
assertEquals( 80d, Round.roundTo(65d, 40d), 0.00000001d );
assertEquals( 0d, Round.roundTo(0d, 0.1d), 0.00000001d);
} }
@Test @Test
@ -27,5 +29,4 @@ public class RoundTest {
assertEquals( 0.6d, Round.ceilTo(0.54d, 0.1d), 0.00000001d ); assertEquals( 0.6d, Round.ceilTo(0.54d, 0.1d), 0.00000001d );
assertEquals( 2d, Round.ceilTo(1.49999d, 1d), 0.00000001d ); assertEquals( 2d, Round.ceilTo(1.49999d, 1d), 0.00000001d );
} }
} }