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6ee917b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 | import Foundation
extension Sequence where Element == Float {
func mean() -> Float {
var sum: Float = 0
var count: Int = 0
for value in self {
sum += value
count += 1
}
return count == 0 ? .nan : sum / Float(count)
}
func onlyNaN() -> Bool {
return first(where: {!$0.isNaN}) == nil
}
func hasValidData() -> Bool {
return !onlyNaN()
}
}
extension Array where Element == Float {
func max(by: Int) -> [Float] {
return stride(from: 0, through: count-by, by: by).map { i in
return self[i..<i+by].max() ?? .nan
}
}
func min(by: Int) -> [Float] {
return stride(from: 0, through: count-by, by: by).map { i in
return self[i..<i+by].min() ?? .nan
}
}
func sum(by: Int) -> [Float] {
return stride(from: 0, through: count-by, by: by).map { i in
return self[i..<i+by].reduce(0, +)
}
}
func sum(by: Float) -> [Float] {
return stride(from: Float(0), through: Float(count)-by, by: by).map { (i: Float) -> Float in
return self[Int(roundf(i))..<Int(roundf(i+by))].reduce(0, +)
}
}
func mean(by: Int) -> [Float] {
return stride(from: 0, through: count-by, by: by).map { i in
return self[i..<i+by].reduce(0, +) / Float(by)
}
}
func meanBackwards(by: Int) -> [Float] {
return stride(from: 0, through: count-by, by: by).map { i in
if i == 0 {
return .nan
}
return self[i-by..<i].reduce(0, +) / Float(by)
}
}
mutating func rounded(digits: Int) {
let roundExponent = powf(10, Float(digits))
for i in indices {
self[i] = Foundation.round(self[i] * roundExponent) / roundExponent
}
}
func round(digits: Int) -> [Float] {
let roundExponent = powf(10, Float(digits))
return map {
return Foundation.round($0 * roundExponent) / roundExponent
}
}
func containsNaN() -> Bool {
return first(where: {$0.isNaN}) != nil
}
mutating func fillWithNaNs() {
for i in self.indices {
self[i] = .nan
}
}
}
extension Array where Element == Float {
/// Shift longitudes by 180° and flip south.north
mutating func shift180LongitudeAndFlipLatitude(nt: Int, ny: Int, nx: Int) {
precondition(nt * ny * nx == count)
self.withUnsafeMutableBufferPointer { data in
/// Data starts eastwards at 0°E... rotate to start at -180°E
for t in 0..<nt {
for y in 0..<ny {
for x in 0..<nx/2 {
let offset = t*nx*ny + y*nx
let val = data[offset + x]
data[offset + x] = data[offset + x + nx/2]
data[offset + x + nx/2] = val
}
}
/// Also flip south / north
for y in 0..<ny/2 {
for x in 0..<nx {
let val = data[t*nx*ny + y*nx + x]
data[t*nx*ny + y*nx + x] = data[t*nx*ny + (ny-1-y)*nx + x]
data[t*nx*ny + (ny-1-y)*nx + x] = val
}
}
}
}
}
/// Shift longitudes by 180°
mutating func shift180Longitude(nt: Int, ny: Int, nx: Int) {
precondition(nt * ny * nx == count)
self.withUnsafeMutableBufferPointer { data in
/// Data starts eastwards at 0°E... rotate to start at -180°E
for t in 0..<nt {
for y in 0..<ny {
for x in 0..<nx/2 {
let offset = t*nx*ny + y*nx
let val = data[offset + x]
data[offset + x] = data[offset + x + nx/2]
data[offset + x + nx/2] = val
}
}
}
}
}
/// Flip south.north
mutating func flipLatitude(nt: Int, ny: Int, nx: Int) {
precondition(nt * ny * nx == count)
self.withUnsafeMutableBufferPointer { data in
for t in 0..<nt {
/// Also flip south / north
for y in 0..<ny/2 {
for x in 0..<nx {
let val = data[t*nx*ny + y*nx + x]
data[t*nx*ny + y*nx + x] = data[t*nx*ny + (ny-1-y)*nx + x]
data[t*nx*ny + (ny-1-y)*nx + x] = val
}
}
}
}
}
mutating func multiplyAdd(multiply: Float, add: Float) {
self.withUnsafeMutableBufferPointer { data in
for i in 0..<data.count {
data[i] = fma(data[i], multiply, add)
}
}
}
/// Perform a simple delta encoding. Leave the first value as seed.
mutating func deltaEncode() {
if count <= 1 {
return
}
for x in (1..<count).reversed() {
if self[x-1].isNaN {
continue
}
self[x] = self[x-1] - self[x]
}
}
/// Undo delta coding
mutating func deltaDecode() {
if count <= 1 {
return
}
for x in 1..<count {
if self[x-1].isNaN {
continue
}
self[x] = self[x-1] - self[x]
}
}
/// Ensure data is greater equals than
mutating func greater(than value: Float) {
for x in 0..<count {
self[x] = Swift.max(self[x], value)
}
}
}
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