ggsoft

package app.model

import app.util.Cfg
import scala.util.Failure
import anorm._

trait Entity[A] {

  val parser: RowParser[A]
  val sql: String

ggsoft

  def sqrt(a: BigDecimal, scale: Int = 0): BigDecimal = {

    def sqrt(a: BigInt): BigInt = { // find b: BigInt => b^2 <= a < (b + 1)^2
      if (a < 0) throw new ArithmeticException("Square root of negative number")
      else if (a < 2) a
      else {
        def next(n: BigInt, i: BigInt): BigInt = (n + i/n) >> 1
        var n0 = BigInt(2).pow((a.bitLength >> 1) + (a.bitLength & 1))
        var n1 = next(n0, a)
        while ((n1 - n0).abs > 1) {

ggsoft

// Algorithms based on the Fibonacci series implementation: 1,1,2,3,5,8,13,21,34,55,...

def fib(n: Int): BigInt = {
  if (n < 1) 0 
  else if (n < 3) 1 
  else fib(n-1) + fib(n-2)
}

// Exponential (very slow, for n> 40 we can see that)