Merge pull request #1315 from haileyajohnson/revert-nearly-equals

revert switch to fuzzy equals
Unidata · Mar 12, 2024 · e57f760 · e57f760
2 parents a2c7146 + 3bb2909
commit e57f760
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Showing 2 changed files with 23 additions and 6 deletions.
diff --git a/cdm/core/src/main/java/ucar/nc2/util/Misc.java b/cdm/core/src/main/java/ucar/nc2/util/Misc.java
@@ -96,19 +96,19 @@ public static boolean nearlyEquals(float a, float b) {
     return nearlyEquals(a, b, defaultMaxRelativeDiffFloat);
   }
 
-  /** AbsoluteDifference is less than maxAbsDiff. */
-  public static boolean nearlyEquals(float a, float b, float maxAbsDiff) {
-    return DoubleMath.fuzzyEquals(a, b, maxAbsDiff);
+  /** RelativeDifference is less than maxRelDiff. */
+  public static boolean nearlyEquals(float a, float b, float maxRelDiff) {
+    return relativeDifference(a, b) < maxRelDiff;
   }
 
   /** AbsoluteDifference is less than {@link #defaultMaxRelativeDiffDouble}. */
   public static boolean nearlyEquals(double a, double b) {
     return nearlyEquals(a, b, defaultMaxRelativeDiffDouble);
   }
 
-  /** AbsoluteDifference is less than maxAbsDiff. */
-  public static boolean nearlyEquals(double a, double b, double maxAbsDiff) {
-    return DoubleMath.fuzzyEquals(a, b, maxAbsDiff);
+  /** RelativeDifference is less than maxRelDiff. */
+  public static boolean nearlyEquals(double a, double b, double maxRelDiff) {
+    return relativeDifference(a, b) < maxRelDiff;
   }
 
   /** AbsoluteDifference is less than maxAbsDiff. */

diff --git a/cdm/core/src/test/java/ucar/nc2/filter/TestEnhancements.java b/cdm/core/src/test/java/ucar/nc2/filter/TestEnhancements.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import java.io.IOException;
+import java.util.Arrays;
 
 public class TestEnhancements {
 
@@ -75,6 +76,13 @@ public static void setUp() throws IOException, InvalidRangeException {
         .addAttribute(new Attribute(CDM.FILL_VALUE, SIGNED_SCALED_FILL_VALUE))
         .addAttribute(new Attribute(CDM.MISSING_VALUE, SIGNED_SCALED_MISSING_VALUE));
 
+    // short data with small scale and offsets
+    Array smallVals = Array.factory(DataType.FLOAT, new int[] {dataLen}, missingData);
+
+    builder.addVariable("smallVals", DataType.FLOAT, "dim").addAttribute(new Attribute(CDM.SCALE_FACTOR, 1e-12))
+        .addAttribute(new Attribute(CDM.ADD_OFFSET, 1e-12)).addAttribute(new Attribute(CDM.FILL_VALUE, 110));
+
+
     // write data
     NetcdfFormatWriter writer = builder.build();
     writer.write(writer.findVariable("signedVar"), new int[1], signedData);
@@ -85,6 +93,7 @@ public static void setUp() throws IOException, InvalidRangeException {
     writer.write(writer.findVariable("validMinMax"), new int[1], missingDataArray);
     writer.write(writer.findVariable("validRange"), new int[1], missingDataArray);
     writer.write(writer.findVariable("enhanceAll"), new int[1], enhanceAllArray);
+    writer.write(writer.findVariable("smallVals"), new int[1], smallVals);
     writer.close();
     ncd = NetcdfDatasets.openDataset(filePath);
   }
@@ -152,4 +161,12 @@ public void testCombinedEnhancements() throws IOException {
     Array data = v.read();
     assertThat((double[]) data.copyTo1DJavaArray()).isEqualTo(expected);
   }
+
+  @Test
+  public void testConvertMissingWithSmallScaleAndOffset() throws IOException {
+    Variable v = ncd.findVariable("smallVals");
+    Array data = v.read();
+    assertThat(Double.isNaN(data.getDouble(2))).isTrue();
+    assertThat(Double.isNaN(data.getDouble(1))).isFalse();
+  }
 }