Almkvist-Giullera formula for pi: Difference between revisions
Add Scala implementation
m (→{{header|RPL}}: improved layout) |
(Add Scala implementation) |
||
Line 2,297:
1: iterations:53
</pre>
=={{header|Scala}}==
<syntaxhighlight lang="Scala">
import java.math.{BigDecimal, BigInteger, MathContext, RoundingMode}
object AlmkvistGiulleraFormula extends App {
println("n Integer part")
println("================================================")
for (n <- 0 to 9) {
val term = almkvistGiullera(n).toString
println(f"$n%1d" + " " * (47 - term.length) + term)
}
val decimalPlaces = 70
val mathContext = new MathContext(decimalPlaces + 1, RoundingMode.HALF_EVEN)
val epsilon = BigDecimal.ONE.divide(BigDecimal.TEN.pow(decimalPlaces))
var previous = BigDecimal.ONE
var sum = BigDecimal.ZERO
var pi = BigDecimal.ZERO
var n = 0
while (pi.subtract(previous).abs.compareTo(epsilon) >= 0) {
val nextTerm = new BigDecimal(almkvistGiullera(n)).divide(BigDecimal.TEN.pow(6 * n + 3))
sum = sum.add(nextTerm)
previous = pi
n += 1
pi = BigDecimal.ONE.divide(sum, mathContext).sqrt(mathContext)
}
println("\npi to " + decimalPlaces + " decimal places:")
println(pi)
def almkvistGiullera(aN: Int): BigInteger = {
val term1 = factorial(6 * aN).multiply(BigInteger.valueOf(32))
val term2 = BigInteger.valueOf(532 * aN * aN + 126 * aN + 9)
val term3 = factorial(aN).pow(6).multiply(BigInteger.valueOf(3))
term1.multiply(term2).divide(term3)
}
def factorial(aNumber: Int): BigInteger = {
var result = BigInteger.ONE
for (i <- 2 to aNumber) {
result = result.multiply(BigInteger.valueOf(i))
}
result
}
}
</syntaxhighlight>
{{out}}
<pre>
n Integer part
================================================
0 96
1 5122560
2 190722470400
3 7574824857600000
4 312546150372456000000
5 13207874703225491420651520
6 567273919793089083292259942400
7 24650600248172987140112763715584000
8 1080657854354639453670407474439566400000
9 47701779391594966287470570490839978880000000
pi to 70 decimal places:
3.1415926535897932384626433832795028841971693993751058209749445923078164
</pre>
=={{header|Sidef}}==
| |||