Fix Lerp panic

WinPooh32 · Feb 19, 2023 · 7fe7fbb · 7fe7fbb
1 parent 4bf6bf2
commit 7fe7fbb
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Showing 2 changed files with 22 additions and 4 deletions.
diff --git a/data.go b/data.go
@@ -888,15 +888,15 @@ func (d Data) Lerp() Data {
 
 	// Find first non-NaN value.
 	for i := 0; ; i++ {
-		if v := values[i]; !IsNA(v) {
-			beg = i
-			break
-		}
 		if i >= len(values) {
 			// All values are NaNs.
 			// Exit.
 			return d
 		}
+		if v := values[i]; !IsNA(v) {
+			beg = i
+			break
+		}
 	}
 
 	var left, right DType

diff --git a/data_test.go b/data_test.go
@@ -1585,6 +1585,24 @@ func TestData_Lerp(t *testing.T) {
 				[]DType{NaN, 2, 5, 7, 9, 11, 13.5, 16, NaN, NaN, NaN},
 			),
 		},
+		{
+			"no gaps",
+			fields{1, []int64{0, 1, 2, 3, 4}, []DType{0, 1, 2, 3, 4}},
+			MakeData(
+				1,
+				[]int64{0, 1, 2, 3, 4},
+				[]DType{0, 1, 2, 3, 4},
+			),
+		},
+		{
+			"all nans",
+			fields{1, []int64{0, 1, 2, 3, 4}, []DType{NaN, NaN, NaN, NaN, NaN}},
+			MakeData(
+				1,
+				[]int64{0, 1, 2, 3, 4},
+				[]DType{NaN, NaN, NaN, NaN, NaN},
+			),
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {