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slices: use !{{Less}} instead of {{GreaterOrEqual}}

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In CL 371574 PatchSet 18, we replaced all !{{Less}} with {{GreaterOrEqual}} to fix a problem(handle NaNs when sorting float64 slice) in exp/slices.

We don't actually need this change, because we don't guarantee that the slice will be sorted eventually if there are NaNs(we could have a[i] < a[j] for some i,j with i>j).

This CL reverts all the replacements in exp/slices and does not affect any codes in the sort package.

Change-Id: Idc225d480de3e2efef2add35c709ed880d1306cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/400534
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Eli Bendersky <eliben@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@google.com>
This commit is contained in:
张云浩 2022-04-15 07:45:17 +00:00 committed by Gopher Robot
parent 60178e6240
commit 415e3fd8a6
1 changed files with 10 additions and 22 deletions
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32
src/sort/gen_sort_variants.go
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@ -84,9 +84,6 @@ func main() {
ExtraArg: "",
DataType: "[]E",
Funcs: template.FuncMap{
"GreaterOrEqual": func(name, i, j string) string {
return fmt.Sprintf("(%s[%s] >= %s[%s])", name, i, name, j)
},
"Less": func(name, i, j string) string {
return fmt.Sprintf("(%s[%s] < %s[%s])", name, i, name, j)
},
@ -106,9 +103,6 @@ func main() {
ExtraArg: ", less",
DataType: "[]E",
Funcs: template.FuncMap{
"GreaterOrEqual": func(name, i, j string) string {
return fmt.Sprintf("!less(%s[%s], %s[%s])", name, i, name, j)
},
"Less": func(name, i, j string) string {
return fmt.Sprintf("less(%s[%s], %s[%s])", name, i, name, j)
},
@ -129,9 +123,6 @@ func main() {
ExtraArg: "",
DataType: "Interface",
Funcs: template.FuncMap{
"GreaterOrEqual": func(name, i, j string) string {
return fmt.Sprintf("!%s.Less(%s, %s)", name, i, j)
},
"Less": func(name, i, j string) string {
return fmt.Sprintf("%s.Less(%s, %s)", name, i, j)
},
@ -152,9 +143,6 @@ func main() {
ExtraArg: "",
DataType: "lessSwap",
Funcs: template.FuncMap{
"GreaterOrEqual": func(name, i, j string) string {
return fmt.Sprintf("!%s.Less(%s, %s)", name, i, j)
},
"Less": func(name, i, j string) string {
return fmt.Sprintf("%s.Less(%s, %s)", name, i, j)
},
@ -222,7 +210,7 @@ func siftDown{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, lo, hi, first int
if child+1 < hi && {{Less "data" "first+child" "first+child+1"}} {
child++
}
if {{GreaterOrEqual "data" "first+root" "first+child"}} {
if !{{Less "data" "first+root" "first+child"}} {
return
}
{{Swap "data" "first+root" "first+child"}}
@ -300,7 +288,7 @@ func pdqsort{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, b, limit int {{
// Probably the slice contains many duplicate elements, partition the slice into
// elements equal to and elements greater than the pivot.
if a > 0 && {{GreaterOrEqual "data" "a-1" "pivot"}} {
if a > 0 && !{{Less "data" "a-1" "pivot"}} {
mid := partitionEqual{{.FuncSuffix}}(data, a, b, pivot {{.ExtraArg}})
a = mid
continue
@ -334,7 +322,7 @@ func partition{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, b, pivot int
for i <= j && {{Less "data" "i" "a"}} {
i++
}
for i <= j && {{GreaterOrEqual "data" "j" "a"}} {
for i <= j && !{{Less "data" "j" "a"}} {
j--
}
if i > j {
@ -349,7 +337,7 @@ func partition{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, b, pivot int
for i <= j && {{Less "data" "i" "a"}} {
i++
}
for i <= j && {{GreaterOrEqual "data" "j" "a"}} {
for i <= j && !{{Less "data" "j" "a"}} {
j--
}
if i > j {
@ -370,7 +358,7 @@ func partitionEqual{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, b, pivot
i, j := a+1, b-1 // i and j are inclusive of the elements remaining to be partitioned
for {
for i <= j && {{GreaterOrEqual "data" "a" "i"}} {
for i <= j && !{{Less "data" "a" "i"}} {
i++
}
for i <= j && {{Less "data" "a" "j"}} {
@ -394,7 +382,7 @@ func partialInsertionSort{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, b
)
i := a + 1
for j := 0; j < maxSteps; j++ {
for i < b && {{GreaterOrEqual "data" "i" "i-1"}} {
for i < b && !{{Less "data" "i" "i-1"}} {
i++
}
@ -411,7 +399,7 @@ func partialInsertionSort{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, b
// Shift the smaller one to the left.
if i-a >= 2 {
for j := i - 1; j >= 1; j-- {
if {{GreaterOrEqual "data" "j" "j-1"}} {
if !{{Less "data" "j" "j-1"}} {
break
}
{{Swap "data" "j" "j-1"}}
@ -420,7 +408,7 @@ func partialInsertionSort{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, b
// Shift the greater one to the right.
if b-i >= 2 {
for j := i + 1; j < b; j++ {
if {{GreaterOrEqual "data" "j" "j-1"}} {
if !{{Less "data" "j" "j-1"}} {
break
}
{{Swap "data" "j" "j-1"}}
@ -606,7 +594,7 @@ func symMerge{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, m, b int {{.Ex
j := m
for i < j {
h := int(uint(i+j) >> 1)
if {{GreaterOrEqual "data" "m" "h"}} {
if !{{Less "data" "m" "h"}} {
i = h + 1
} else {
j = h
@ -633,7 +621,7 @@ func symMerge{{.FuncSuffix}}{{.TypeParam}}(data {{.DataType}}, a, m, b int {{.Ex
for start < r {
c := int(uint(start+r) >> 1)
if {{GreaterOrEqual "data" "p-c" "c"}} {
if !{{Less "data" "p-c" "c"}} {
start = c + 1
} else {
r = c