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Weights that start too big or too small make deep networks hard to train. Two standard schemes pick the scale from the layer size, where fan_in is the number of inputs and fan_out the number of outputs:
| method | returns |
|---|---|
"xavier_uniform" | limit √(6 / (fan_in + fan_out)), weights drawn from [-limit, limit] |
"xavier_normal" | standard deviation √(2 / (fan_in + fan_out)) |
"he_uniform" | limit √(6 / fan_in) |
"he_normal" | standard deviation √(2 / fan_in) |
Xavier (Glorot) suits sigmoid and tanh layers; He suits ReLU layers.
Implement init_bound(method, fan_in, fan_out).
Input
method: One of "xavier_uniform", "xavier_normal", "he_uniform" or "he_normal".
fan_in, fan_out: The layer's number of inputs and outputs.
Output
Return the limit or standard deviation as a decimal number.
Constraints
1 ≤ fan_in, fan_out ≤ 100,000
Examples
Example 1
Input:
method = "xavier_uniform"
fan_in = 3
fan_out = 3
Expected output:
1.0Explanation
√(6 / (3 + 3)) = √1 = 1, so weights are drawn from [-1, 1].
Example 2
Input:
method = "he_normal"
fan_in = 50
fan_out = 10
Expected output:
0.2Explanation
He only uses fan_in: √(2 / 50) = √0.04 = 0.2.
References
-
Example 1 Not runInput:
method = "xavier_uniform" fan_in = 3 fan_out = 3Expected output:1.0Your output -
Example 2 Not runInput:
method = "he_normal" fan_in = 50 fan_out = 10Expected output:0.2Your output
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💡 Kotlin Basics Guide for Beginners
1. Declaring Variables and Constants
Kotlin uses val for immutable variables and var for mutable ones.
val name: String = "Alice"
var age: Int = 30
val pi = 3.14 // type inferred
// Constants
const val MAX_USERS = 1002. Conditionals (if / when)
Use if expressions or when for multiple branches.
val x = 2
if (x == 1) {
println("One")
} else if (x == 2) {
println("Two")
} else {
println("Other")
}
when (x) {
1 -> println("One")
2 -> println("Two")
else -> println("Other")
}3. Loops
Use for, while, and do-while for iteration.
for (i in 0..2) {
println(i)
}
var n = 3
while (n > 0) {
println(n)
n--
}4. Arrays
Kotlin supports arrays using the arrayOf() function.
val numbers = arrayOf(10, 20, 30)
println(numbers[1])5. List Manipulation
Use mutableListOf for dynamic lists.
val nums = mutableListOf(1, 2, 3)
nums.add(4)
nums.removeAt(0)
for (n in nums) {
print("$n ")
}6. Console Input/Output
Use readLine() for input and println() for output.
print("Enter your name: ")
val name = readLine()
println("Hello, $name")7. Functions
Functions use fun keyword with optional return type.
fun add(a: Int, b: Int): Int {
return a + b
}
println(add(3, 4))8. Maps
mutableMapOf stores key-value pairs.
val ages = mutableMapOf("Alice" to 30)
println(ages["Alice"])9. Exception Handling
Use try, catch, and finally to handle errors.
try {
val result = 10 / 0
} catch (e: ArithmeticException) {
println("Error: ${e.message}")
}10. File I/O
Use File from java.io for file operations.
import java.io.File
File("file.txt").writeText("Hello File")
val text = File("file.txt").readText()
println(text)11. String Manipulation
Kotlin strings support many methods and interpolation.
val text = "Hello World"
println(text.length)
println(text.substring(0, 5))
println(text.contains("World"))12. Classes & Objects
Kotlin classes are concise and support default constructors.
class Person(val name: String) {
fun greet() = println("Hi, I'm $name")
}
val p = Person("Alice")
p.greet()13. Null Safety
Kotlin distinguishes nullable and non-nullable types. Use ? and ?: for safety.
val name: String? = null
println(name?.length ?: 0)