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Apply a digital filter (direct form II transposed): Difference between revisions
Apply a digital filter (direct form II transposed) (view source)
Revision as of 10:25, 10 September 2019
, 4 years agoScala contribution added.
(Scala contribution added.) |
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</pre>
=={{header|Scala}}==
{{Out}}See it yourself by running in your browser either by [https://scalafiddle.io/sf/0D4zyWF/0 ScalaFiddle (ES aka JavaScript, non JVM)] or [https://scastie.scala-lang.org/mUPbvXTQTXijp2DV1piQgQ Scastie (remote JVM)].
{{libheader|Scala Tail recursion}}
{{libheader|Scala Digital Signal Processing}}
{{libheader|ScalaFiddle qualified}}
{{libheader|Scastie qualified}}
{{works with|Scala|2.13}}
<lang Scala>object ButterworthFilter extends App {
private def filter(a: Vector[Double],
b: Vector[Double],
signal: Vector[Double]): Vector[Double] = {
@scala.annotation.tailrec
def outer(i: Int, acc: Vector[Double]): Vector[Double] = {
if (i >= signal.length) acc
else {
@scala.annotation.tailrec
def inner0(j: Int, tmp: Double): Double = if (j >= b.length) tmp
else if ((i - j) >= 0) inner0(j + 1, tmp + b(j) * signal(i - j)) else inner0(j + 1, tmp)
@scala.annotation.tailrec
def inner1(j: Int, tmp: Double): Double = if (j >= a.length) tmp
else if (i - j >= 0) inner1(j + 1, tmp - a(j) * acc(i - j)) else inner1(j + 1, tmp)
outer(i + 1, acc :+ inner1(1, inner0(0, 0D)) / a(0))
}
}
outer(0, Vector())
}
filter(Vector[Double](1, -2.77555756e-16, 3.33333333e-01, -1.85037171e-17),
Vector[Double](0.16666667, 0.5, 0.5, 0.16666667),
Vector[Double](
-0.917843918645, 0.141984778794, 1.20536903482, 0.190286794412, -0.662370894973,
-1.00700480494, -0.404707073677, 0.800482325044, 0.743500089861, 1.01090520172,
0.741527555207, 0.277841675195, 0.400833448236, -0.2085993586, -0.172842103641,
-0.134316096293, 0.0259303398477, 0.490105989562, 0.549391221511, 0.9047198589)
).grouped(5)
.map(_.map(x => f"$x% .8f"))
.foreach(line => println(line.mkString(" ")))
}</lang>
=={{header|Sidef}}==
{{trans|Perl 6}}
Line 1,070 ⟶ 1,113:
0.96185430, 0.69569009, 0.42435630, 0.19626223, -0.02783512,
-0.21172192, -0.17474556, 0.06925841, 0.38544587, 0.65177084
]</pre>▼
▲</pre>
=={{header|Yabasic}}==
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