Apply a digital filter (direct form II transposed): Difference between revisions

{{trans|Nim}}

V result = [0.0] * signal.len

L(i) 0 .< signal.len

=={{header|Ada}}==

procedure Apply_Filter is

{{Trans|C++}} ... via Yabasic<br>

The default lower bound in Algol 68 arrays is 1, so the loops/subscripts have been adjusted accordingly.

PROC filter = ( []REAL a, b, signal, REF[]REAL result )VOID:

BEGIN

=={{header|AppleScript}}==

{{trans|Julia}} — except that j starts from 2 in the second inner repeat, there being no point in fetching and performing math with the zero about to be overwritten. This change in turn allows the result list to be populated on the fly instead of being pre-populated with zeros.

if (b < a) then return b

return a

{{output}}

=={{header|C}}==

Given the number of values a coefficient or signal vector can have and the number of digits, this implementation reads data from a file and prints it to the console if no output file is specified or writes to the specified output file. Usage printed on incorrect invocation.

#include<stdlib.h>

#include<string.h>

=={{header|C sharp|C#}}==

{{trans|Java}}

namespace ApplyDigitalFilter {

This uses the C++11 method of initializing vectors. In g++, use the -std=c++0x compiler switch.

#include <iostream>

using namespace std;

=={{header|Common Lisp}}==

{{trans|zkl}}

(defparameter b #(0.16666667L0 0.50000000L0 0.50000000L0 0.16666667L0))

(defparameter s #(-0.917843918645 0.141984778794 1.20536903482 0.190286794412 -0.662370894973

=={{header|D}}==

{{trans|Kotlin}}

alias T = real;

=={{header|FreeBASIC}}==

{{trans|Yabasic}}

Dim As Integer j, k

Dim As Double tmp

=={{header|Go}}==

import "fmt"

=={{header|Groovy}}==

{{trans|Java}}

private static double[] filter(double[] a, double[] b, double[] signal) {

double[] result = new double[signal.length]

=={{header|Haskell}}==

The solution is based not on the explicit loops, as in strict imperative languages, but on lazy recursive trick known as "tying a knot".

-- lazy convolution of a list by given kernel

There's probably a nicer way to do this:

t=. (#n) +/ .*&(|.n)\(}.n*0),y

A=.|.}.m

=={{header|Java}}==

{{trans|Kotlin}}

private static double[] filter(double[] a, double[] b, double[] signal) {

double[] result = new double[signal.length];

=={{header|Julia}}==

{{trans|zkl}}

rst = zeros(sig)

for i in eachindex(sig)

=={{header|Kotlin}}==

{{trans|C++}}

fun filter(a: DoubleArray, b: DoubleArray, signal: DoubleArray): DoubleArray {

=={{header|Lua}}==

{{trans|C++}}

local out = {}

for i=1,table.getn(input) do

=={{header|Mathematica}}/{{header|Wolfram Language}}==

a = {1.00000000, -2.77555756*^-16, 3.33333333*^-01, -1.85037171*^-17};

signal = {-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};

=={{header|MATLAB}}==

MATLAB is commonly used for filter design and implementation. To implement this filter, and display the original signal and the filtered result:

signal = [-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];

a = [1.00000000, -2.77555756e-16, 3.33333333e-01, -1.85037171e-17];

=={{header|Nim}}==

{{trans|Kotlin}}

import strformat

=={{header|Objeck}}==

{{trans|Java}}

function : Main(args : String[]) ~ Nil {

a := [1.00000000, -2.77555756e-16, 3.33333333e-01, -1.85037171e-17];

=={{header|ooRexx}}==

a=.array~of(1.00000000, -2.77555756e-16, 3.33333333e-01, -1.85037171e-17)

b=.array~of(0.16666667, 0.5, 0.5, 0.16666667)

=={{header|Perl}}==

{{trans|Raku}}

use List::AllUtils 'natatime';

Note however that the a[j]* starts from index 2, unlike Julia/C/Raku/Rust/Sidef/zkl,

but the same as C++/C#/D/Java/Kotlin - and it does not seem to make any difference...

<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>

<span style="color: #008080;">function</span> <span style="color: #000000;">direct_form_II_transposed_filter</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">signal</span><span style="color: #0000FF;">)</span>

=={{header|Phixmonti}}==

{{trans|Phix}}

( 1.00000000 -2.77555756e-16 3.33333333e-01 -1.85037171e-17 ) var a

=={{header|Python}}==

from __future__ import print_function

from scipy import signal

{{trans|C}} Strangely, C was more informative than Common Lisp in helping figure out what was going on here.

(define a (vector 1.00000000E0 -2.77555756E-16 3.33333333E-01 -1.85037171E-17))

{{trans|zkl}}

my @out = 0 xx @signal;

for ^@signal -> $i {

===version 1===

{{trans|Julia}}

@a= '1 -2.77555756e-16 3.33333333e-1 -1.85037171e-17' /*filter coefficients*/

@b= 0.16666667 0.5 0.5 0.16666667 /* " " */

===version 2===

{{trans|Julia}}

Numeric Digits 24

acoef = '1.00000000, -2.77555756e-16, 3.33333333e-01, -1.85037171e-17'

=={{header|Ruby}}==

{{trans|C#}}

result = Array.new(signal.length(), 0.0)

for i in 0..signal.length()-1 do

=={{header|Rust}}==

{{trans|Java}}

struct IIRFilter<'f>(&'f [f32], &'f [f32]);

{{libheader|Scastie qualified}}

{{works with|Scala|2.13}}

private def filter(a: Vector[Double],

b: Vector[Double],

=={{header|Sidef}}==

{{trans|Raku}}

var out = [0]*signal.len

for i in ^signal {

=={{header|Visual Basic .NET}}==

{{trans|C#}}

Function Filter(a As Double(), b As Double(), signal As Double()) As Double()

=={{header|Vlang}}==

{{trans|Go}}

b []f64

a []f64

{{trans|Kotlin}}

{{libheader|Wren-fmt}}

var filter = Fn.new { |a, b, signal|

=={{header|Yabasic}}==

{{trans|D}}

local i, j, tmp

=={{header|zkl}}==

{{trans|C++}}

out:=List.createLong(signal.len(),0.0); // vector of zeros

foreach i in (signal.len()){

out

}</syntaxhighlight>

-0.662370894973,-1.00700480494, -0.404707073677, 0.800482325044,

0.743500089861, 1.01090520172, 0.741527555207, 0.277841675195,