FOSSEE Winter Internship 2024 work done by Abinash Singh

8 files changed, 193 insertions, 155 deletions

diff --git a/macros/besselap.sci b/macros/besselap.sci
index 2ed0047..1e7d952 100644
--- a/macros/besselap.sci
+++ b/macros/besselap.sci
@@ -1,17 +1,14 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
-// Original contribution: FOSSEE, IIT Bombay
 // Original Source : https://octave.sourceforge.io/signal/
-// Modifieded by: Sonu Sharma, RGIT Mumbai
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Date of Modification: 3 Feb 2024
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
-
-
 function [zero, pole, gain]=besselap(n)
     //Bessel analog filter prototype.
 
@@ -44,38 +41,44 @@ function [zero, pole, gain]=besselap(n)
     // zero  =
     //
     //     []
-
+    // Dependencies
+    // prepad
 
 
     funcprot(0);
     [nargout, nargin] = argn() ;
-
     if (nargin>1 | nargin<1)
         error("besselap : wrong number of input argument")
     end
-
     // interpret the input parameters
     if (~(length(n)==1 & n == round(n) & n > 0))
         error ("besselap: filter order n must be a positive integer");
     end
-
     p0=1;
     p1=[1 1];
     for nn=2:n
         px=(2*nn-1)*p1;
         py=[p0 0 0];
-        px=prepad(px,max(length(px),length(py)),0);
+        px=prepad(px,max(length(px),length(py)));
         py=prepad(py,length(px));
         p0=p1;
         p1=px+py;
     end
     // p1 now contains the reverse bessel polynomial for n
-
     // scale it by replacing s->s/w0 so that the gain becomes 1
     p1=p1.*p1(length(p1)).^((length(p1)-1:-1:0)/(length(p1)-1));
-
     zero=[];
     pole=roots(p1);
     gain=1;
-
 endfunction
+
+/* 
+Note : The function is tested with Octave's outputs as a reference.
+# all passed 
+[zero, pole, gain] = besselap (1) 
+[zero, pole, gain] = besselap (2)
+[zero, pole, gain] = besselap (7)
+[zero, pole, gain] = besselap (13)
+[zero, pole, gain] = besselap (43)    
+
+*/
\ No newline at end of file
diff --git a/macros/besself.sci b/macros/besself.sci
index c52f3ac..a6eef80 100644
--- a/macros/besself.sci
+++ b/macros/besself.sci
@@ -1,15 +1,14 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
 // Original Source : https://octave.sourceforge.io/signal/
-// Modifieded by:Sonu Sharma, RGIT Mumbai
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Date of Modification: 3 Feb 2024
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
-
 function [a, b, c, d] = besself (n, w, varargin)
     //Bessel filter design.
 
@@ -20,22 +19,17 @@ function [a, b, c, d] = besself (n, w, varargin)
     //[b, a] = besself (n, [Wl, Wh], "stop")
     //[z, p, g] = besself (…)
     //[…] = besself (…, "z")
-
-
     //Parameters
     //n: positive integer value (order of filter)
     //Wc: positive real value,
     //    1).Analog 3dB cutoff frequency/frequencies for analog filter, in the range [0, Inf] {rad/sec}
     //    2).Normalised digital 3dB cutoff frequency/frequencies for digital filter, in the range [0, 1] {dimensionless}
-
     //Description
     //This function generates a Bessel filter. The default is a Laplace space (s)  or analog filter.
     //If second argument is scalar the third parameter takes in high or low, the default value being low. The cutoff is Wc rad/sec.
     //If second argument is vector of length 2 ie [Wl Wh] then third parameter may be pass or stop default is pass for bandpass and band reject filter respectively
     //[z,p,g] = besself(...) returns filter as zero-pole-gain rather than coefficients of the numerator and denominator polynomials.
     //[...] = besself(...,’z’) returns a discrete space (Z) filter. Wc must be less than 1 {dimensionless}.
-
-
     //Examples
     //[b, a]=besself(2,.3,"high","z")
     //Output :
@@ -46,14 +40,14 @@ function [a, b, c, d] = besself (n, w, varargin)
     //
     //    0.4668229  - 0.9336457    0.4668229
     //
-
+    // Dependencies
+    // besselap bilinear  sftrans  zp2tf
     funcprot(0);
     [nargout nargin] = argn();
 
     if (nargin > 4 | nargin < 2 | nargout > 4 | nargout < 2)
         error("besself: invalid number of inputs")
     end
-
     // interpret the input parameters
     if (~ (isscalar (n) & (n == fix (n)) & (n > 0)))
         error ("besself: filter order N must be a positive integer");
@@ -79,14 +73,13 @@ function [a, b, c, d] = besself (n, w, varargin)
             error ("besself: expected [high|stop] or [s|z]");
         end
     end
-
     // FIXME: Band-pass and stop-band currently non-functional, remove
     //        this check once low-pass to band-pass transform is implemented.
     if (~ isscalar (w))
         error ("besself: band-pass and stop-band filters not yet implemented");
     end
 
-    [rows_w colums_w] = size(w);
+    [rows_w columns_w] = size(w);
 
     if (~ ((length (w) <= 2) & (rows_w == 1 | columns_w == 1)))
         error ("besself: frequency must be given as WC or [WL, WH]");
@@ -115,7 +108,6 @@ function [a, b, c, d] = besself (n, w, varargin)
     if (digital)
         [zero, pole, gain] = bilinear (zero, pole, gain, T);
     end
-
     // convert to the correct output form
     if (nargout == 2)
         //    a = real (gain * poly (zero));
@@ -127,7 +119,28 @@ function [a, b, c, d] = besself (n, w, varargin)
         c = gain;
     else
         // output ss results
-        //    [a, b, c, d] = zp2ss (zero, pole, gain);
+        // FIXME : test zp2ss 
+        //[a, b, c, d] = zp2ss (zero, pole, gain);
         error("besself: yet not implemented in state-space form OR invalid number of o/p arguments")
     end
 endfunction
+
+/*
+Note : This function is tested with Octave's outputs as a reference.
+# Test input validation
+[a, b] = besself () // error passed
+[a, b] = besself (1) // error passed
+[a, b] = besself (1, 2, 3, 4, 5) // error passed
+[a, b] = besself (.5, .2) // error passed
+[a, b] = besself (3, .2, "invalid") // error passed
+ //[b, a] = besself(n, Wc)
+[b a] = besself(2,1000) // passed
+//[b, a] = besself (n, Wc, "high")
+[b a] = besself(7,0.3,"high") // passed
+//[b, a] = besself (n, [Wl, Wh])
+[b a] = besself(4,[1000 5000]) // error: besself: band-pass and stop-band filters not yet implemented
+//[b, a] = besself (n, [Wl, Wh], "stop")
+[b a] = besself(4,[1000 5000],"stop") // besself: band-pass and stop-band filters not yet implemented
+//[z, p, g] = besself (…)
+[z,p,g] = besself(9,0.8,"high") // passed
+*/
\ No newline at end of file
diff --git a/macros/bilinear.sci b/macros/bilinear.sci
index d1ee3f7..1aa408a 100644
--- a/macros/bilinear.sci
+++ b/macros/bilinear.sci
@@ -1,15 +1,14 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
 // Original Source : https://octave.sourceforge.io/signal/
-// Modifieded by:Sonu Sharma, RGIT Mumbai
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Date of Modification: 3 Feb 2024
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
-
 function [Zz, Zp, Zg] = bilinear(Sz, Sp, Sg, T)
 
     //Transforms a s-plane filter (Analog) into a z-plane filter (Digital) using Bilinear transformation
@@ -48,13 +47,15 @@ function [Zz, Zp, Zg] = bilinear(Sz, Sp, Sg, T)
     // b  =
     //
     //    0.  - 0.1666667  - 0.3333333    2.5
-
+    // Dependencies
+    // tf2zp postpad zp2tf prepad
     funcprot(0);
     [nargout nargin] = argn();
     ieee(2);
 
     if nargin==3
         T = Sg;
+        //  FIXME : tf2zp is not tested yet
         [Sz, Sp, Sg] = tf2zp(Sz, Sp);
     elseif nargin~=4
         error("bilinear: invalid number of inputs")
@@ -77,9 +78,6 @@ function [Zz, Zp, Zg] = bilinear(Sz, Sp, Sg, T)
     if Zg == 0 & nargout == 3 then
         error("bilinear: invalid value of gain due to zero(s) at infinity avoid z-p-g form and use tf form ")
     end
-
-
-
     Zp = (2+Sp*T)./(2-Sp*T);
     SZp = size(Zp);
     if isempty(Sz)
@@ -88,8 +86,6 @@ function [Zz, Zp, Zg] = bilinear(Sz, Sp, Sg, T)
         Zz = [(2+Sz*T)./(2-Sz*T)];
         Zz = postpad(Zz, p, -1);
     end
-
-
     if nargout==2
         // zero at infinity
         Zz1 = [];
@@ -115,3 +111,17 @@ function [Zz, Zp, Zg] = bilinear(Sz, Sp, Sg, T)
     end
 ieee(0);
 endfunction
+/*
+// FIXME- not working with three argument
+
+Note : This function is tested with Octave's outputs as a reference.
+
+[Zb,Za] = bilinear([1 0],[1 1],1,0.5) // passed 
+[Zb, Za] = bilinear([], [], 1, 1) // error PASSED
+[Zb, Za] = bilinear([0], [], 1, 0.5) // error PASSED
+[Zb, Za] = bilinear([], [0], 1, 0.5) // PASSED
+
+[Zb, Za] = bilinear([2], [1], 1, 0.5) // PASSED
+[Zb, Za] = bilinear([1; -1], [0.5; -0.5], 2, 1) //PASSED
+[Zb, Za] = bilinear([0], [1], 1, 1) //PASSED
+*/
\ No newline at end of file
diff --git a/macros/postpad.sci b/macros/postpad.sci
index f8042be..3797e08 100644
--- a/macros/postpad.sci
+++ b/macros/postpad.sci
@@ -1,49 +1,57 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
-// Author:Sonu Sharma, RGIT Mumbai
+// Author: Abinash Singh Under FOSSEE Internship
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Last Modified on : 3 Feb 2024
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
-
-// This is a supporting function
-
-function y = postpad(x, n, varargin)
-
-    //Calling Sequences
-    // Y = postpad (X, L)
-    // Y = postpad (X, L, C)
-
-    // Description :
-    // Append the scalar value C to the vector X until it is of length L.
-    // If C is not given, a value of 0 is used.
-    //
-    // If 'length (X) > L', elements from the end of X are removed until a
-    // vector of length L is obtained.
-
-    //Example :
-    //x = [1 2 3];
-    //L = 6;
-    //y = postpad(x, L)
-    //Output :
-    // y  =
-    //
-    //    1.    2.    3.    0.    0.    0.
-
-    funcprot(0);
-    if argn(2) > 3 | argn(2) < 2  then
-        error("postpad : wrong number of input argument ")
-    elseif argn(2) == 2
+/*
+Calling Sequence :
+    postpad (x, l)
+    postpad (x, l, c)
+    postpad (x, l, c, dim)
+Append the scalar value c to the vector x until it is of length l. If c is not given, a value of 0 is used.
+If length (x) > l, elements from the end of x are removed until a vector of length l is obtained.
+If x is a matrix, elements are appended or removed from each row.
+If the optional argument dim is given, operate along this dimension.
+If dim is larger than the dimensions of x, the result will have dim dimensions.
+*/
+function res = postpad(x,l,c,dim)
+    if nargin < 2 then 
+        error("Usage :  postpad(x,l,c(optional),dim(optional))")
+    end
+    if nargin < 3 then 
         c = 0 ;
-    else
-        c = varargin(1);
     end
-
-    y = x;
-    for i = 1:(n-length(x))
-        y = [y c];
+    if nargin <= 4 then 
+        if size(x,1) == 1 then
+            dim = 1 ;
+        elseif size(x,2) == 1 then 
+            dim = 2 ;
+        else
+            dim = 2 ; // FIXME dim functionality not implemented
+        end
+    end
+    if l < size(x,dim) then
+        error("l must be greater then dimension of x")
+    end
+    
+    select dim
+    case 1 then
+        res = [x c*ones(size(x,1),l-size(x,2))];
+    case 2 then
+        res = [x;c*ones(l-size(x,1),size(x,2))];
     end
 endfunction
+
+/*
+#test for row vectors
+postpad([1 2 3 4],6) //passed
+postpad([1 ;2 ;3 ;4],6) // passed
+postpad([1 2 3 4;5 6 7 8;9 10 11 12],6) // passed
+postpad([1 2 ;3 4;5 6],6,-1) //passed
+*/
\ No newline at end of file
diff --git a/macros/prepad.sci b/macros/prepad.sci
index 4e517f8..d3595bf 100644
--- a/macros/prepad.sci
+++ b/macros/prepad.sci
@@ -1,83 +1,65 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
-// Author:[insert name]
+// Author: Abinash Singh Under FOSSEE Internship
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Last Modified on : 3 Feb 2024
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
+/*
+Calling Sequence :
+    prepad (x, l)
+    prepad (x, l, c)
+    prepad (x, l, c, dim)
 
-
-function y = prepad (x, l, c, dim)
-// Calling sequence:
-// y= prepad (x, l)
-// y= prepad (x, l, c)
-// y= prepad (x, l, c, dim)
-// Prepend the scalar value c to the vector x until it is of length
-// l.  If c is not given, a value of 0 is used.
-//
-// If length (x) > l, elements from the beginning of x
-// are removed until a vector of length l is obtained.
-//
-// If x is a matrix, elements are prepended or removed from each row.
-//
-// If the optional argument dim is given, operate along this dimension.
-//
-// If dim is larger than the dimensions of x, the result will have
-// dim dimensions.
-
-//Test cases:
-//prepad ([1,2], 4,0,2)
-//Output: [0,0,1,2]
-
-
-[nargout,nargin]=argn();
-  if (nargin < 2 | nargin > 4)
-    error("wrong number of input arguments");
-  end
-
-  if (nargin < 3 | isempty (c))
-    c = 0;
-  else
-    if (~ isscalar (c))
-      error ("prepad: pad value C must be empty or a scalar");
+Prepend the scalar value c to the vector x until it is of length l. If c is not given, a value of 0 is used.
+If length (x) > l, elements from the beginning of x are removed until a vector of length l is obtained.
+If x is a matrix, elements are prepended or removed from each row.
+If the optional argument dim is given, operate along this dimension.
+If dim is larger than the dimensions of x, the result will have dim dimensions.
+*/
+function res = prepad(x,l,c,dim)
+    if nargin < 2 then 
+        error("Usage :  postpad(x,l,c(optional),dim(optional))")
     end
-  end
-//dim=1;
-  nd = ndims (x);
-  sz = size (x);
-  if (argn(2) < 4)
-    // Find the first non-singleton dimension.
-    dim = find (sz > 1, 1)
-    if (dim == [])
-      dim = 1
+    if nargin < 3 then 
+        c = 0 ;
     end
-  else
-    if (~(isscalar (dim) & dim == fix (dim) & dim >= 1))
-      error ("prepad: DIM must be an integer and a valid dimension");
+    if nargin < 4 then 
+        dim = find(size(x)>1)
+        if isempty(dim) then dim = 2 end
+        if isvector(dim) then dim = dim(1) end
     end
-  end
-
-  if (~ isscalar (l) | l < 0)
-    error ("prepad: length L must be a positive scalar");
-  end
 
-  if (dim > nd)
-    sz(nd+1:dim) = 1;
-  end
-
-  d = sz(dim);
+    if l < size(x,dim) then
+        if isvector(x) then 
+            start = length(x) - l+1;
+            res=x(start:$)
+            return;
+        else
+            error("prepad : l must be greter than dim size for matrices")
+        end
+        
+    end
+    
+    if dim == 1 then 
+        res = [ c* ones( l - size(x,1) , size(x,2)) ; x]
+    elseif dim == 2 then 
+        res = [ c* ones( size(x,1) , l - size(x,2)) x]
+    else
+        error("prepad : Invalid value for arg dim 1 or 2 expected")
+    end
+endfunction
 
-  if (d >= l)
-//    idx = repmat ({':'}, nd, 1);
-//    idx(dim) = (d-l+1) : d;
-//    y = x(idx(:));
-      y=x;
-  else
-    sz(dim) = l - d;
-    y = cat (dim, c(ones (sz(1),sz(2))), x);
-  end
+/*
+#test for row vectors
+prepad([1 2 3 4],6) 
+prepad([1 ;2 ;3 ;4],6) 
+prepad([1 2 3 4;5 6 7 8;9 10 11 12],6) 
+prepad([1 2 ;3 4;5 6],6,-1) 
 
-endfunction
+// FIXME : Tests for 2d and high dimesnsional matrices
+*/
diff --git a/macros/sftrans.sci b/macros/sftrans.sci
index 2dfd2bb..f0c092e 100644
--- a/macros/sftrans.sci
+++ b/macros/sftrans.sci
@@ -1,15 +1,14 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
 // Original Source : https://octave.sourceforge.io/signal/
-// Modifieded by:Sonu Sharma, RGIT Mumbai
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Date of Modification: 3 Feb 2024
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
-
 function [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop)
     //Transform band edges of a prototype filter (cutoff at W=1) represented in s-plane zero-pole-gain form (Frequency Transformation in Analog domain).
 
@@ -71,7 +70,8 @@ function [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop)
     // Sz  =
     //
     //    20.    10.    6.6666667
-
+    // dependencies
+    // 
     funcprot(0);
     [nargout nargin]= argn();
 
@@ -115,12 +115,12 @@ function [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop)
             Sp = [b+sqrt(b.^2-Fh*Fl), b-sqrt(b.^2-Fh*Fl)];
             extend = [sqrt(-Fh*Fl), -sqrt(-Fh*Fl)];
             if isempty(Sz)
-                Sz = [extend(1+rem([1:2*p],2))];
+                Sz = [extend(1+modulo([1:2*p],2))];
             else
                 b = (C*(Fh-Fl)/2)./Sz;
                 Sz = [b+sqrt(b.^2-Fh*Fl), b-sqrt(b.^2-Fh*Fl)];
                 if (p > z)
-                    Sz = [Sz, extend(1+rem([1:2*(p-z)],2))];
+                    Sz = [Sz, extend(1+modulo([1:2*(p-z)],2))];
                 end
             end
         else
@@ -178,3 +178,13 @@ function [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop)
         end
     end
 endfunction
+/**
+Note : This function is tested with Octave's outputs as a reference.
+
+[Sz_new , Sp_new , Sg_new ] = sftrans([0.5;-0.5],[0.3 ; -0.3],2,0.5,0) // passed
+[Sz_new , Sp_new , Sg_new ] = sftrans([0.5;-0.5],[0.3 ; -0.3],2,0.5,1)  // passed
+[Sz_new, Sp_new, Sg_new] = sftrans([0.5], [0.3], 1, [1.0, 2.0], 0)      //passed
+[Sz_new, Sp_new, Sg_new] = sftrans([0.5], [0.3], 1, [1.0, 2.0], 1) //passed
+[Sz_new, Sp_new, Sg_new] = sftrans([], [], 1, 1.0, 0) //error passed
+[Sz_new, Sp_new, Sg_new] = sftrans([0], [], 1, 1.0, 0)//error passed
+*/
\ No newline at end of file
diff --git a/macros/tf2zp.sci b/macros/tf2zp.sci
index ca10fd4..f607ba0 100644
--- a/macros/tf2zp.sci
+++ b/macros/tf2zp.sci
@@ -1,13 +1,14 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
-//Original contribution: FOSSEE, IIT Bombay
+// Original Source : https://octave.sourceforge.io/signal/
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Date of Modification: 3 Feb 2024
+// Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
-
 function [z,p,k]=tf2zp(num,den)
 
     // Transfer function to zero pole conversion
@@ -60,8 +61,9 @@ function [z,p,k]=tf2zp(num,den)
 
     if(rd>1) then
         error("Denominator must be row vector");
-    elseif np>cod then
-        error("Improper transfer function");
+        
+    // elseif np>cod then
+    //      error("Improper transfer function"); it is a bug it should be removed
     end
     if (~isempty(den)) then
         coef=den(1);
@@ -98,3 +100,9 @@ function [z,p,k]=tf2zp(num,den)
     end
     z=roots(num);
 endfunction
+/*
+Note : This function is tested with Octave's outputs as a reference.
+[z p k] = tf2zp([9.6500e+02  -1.1773e+05   3.8648e+06  -4.5127e+071.5581e+08],[ 1  -3   2]) //pass
+[z p k] = tf2zp([1 2 3 4],[ 1  -3   2]) //pass
+[z p k] = tf2zp([4 5 6],[1]) // pass
+*/
\ No newline at end of file
diff --git a/macros/zp2tf.sci b/macros/zp2tf.sci
index da3e8b1..10da276 100644
--- a/macros/zp2tf.sci
+++ b/macros/zp2tf.sci
@@ -1,14 +1,14 @@
 // Copyright (C) 2018 - IIT Bombay - FOSSEE
-//
 // This file must be used under the terms of the CeCILL.
 // This source file is licensed as described in the file COPYING, which
 // you should have received as part of this distribution.  The terms
 // are also available at
 // http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
-// Author:Sonu Sharma, RGIT Mumbai
+// Original Source : https://octave.sourceforge.io/signal/
+// Modifieded by: Abinash Singh Under FOSSEE Internship
+// Date of Modification: 3 Feb 2024
 // Organization: FOSSEE, IIT Bombay
 // Email: toolbox@scilab.in
-
 function [num, den] = zp2tf (z, p, k)
     //Converts zeros / poles to a transfer function.
 
@@ -54,3 +54,7 @@ function [num, den] = zp2tf (z, p, k)
     den = flipdim(den,2);
 
 endfunction
+/*
+[num,den] = zp2tf([1 3 4 5],[-4 -3 1 4],7) //passed
+[num,den] = zp2tf([15 78 6 23],[2 1],965) //passed
+*/
\ No newline at end of file