From c0460d554ac69b218fca3c39fdc4557b6a3512f4 Mon Sep 17 00:00:00 2001
From: Chandra Pratap
Date: Wed, 7 Aug 2024 17:51:44 +0530
Subject: Implement ifftshift1.sci in Scilab

---
 macros/ifftshift1.sci | 105 +++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 82 insertions(+), 23 deletions(-)

diff --git a/macros/ifftshift1.sci b/macros/ifftshift1.sci
index 7426130..c81a285 100644
--- a/macros/ifftshift1.sci
+++ b/macros/ifftshift1.sci
@@ -1,24 +1,83 @@
-function y= ifftshift1(X,DIM)
+function y = ifftshift1(x, dim)
 //Undo the action of the 'fftshift1' function.
-//Calling Sequence
-// ifftshift1 (X)
-// ifftshift1 (X, DIM)
-//Parameters 
-//X:It is a vector of N elements corresponding to time samples
-//DIM: The optional DIM argument can be used to limit the dimension along which the permutation occurs
-//Description
-//This is an Octave function.
-//Undo the action of the 'fftshift1' function.
-//
-//For even length X, 'fftshift1' is its own inverse, but odd lengths differ slightly.
-	rhs= argn(2);
-	if(rhs <1 | rhs >2)
-		error('Wrong number of Input arguments');
-	end
-	select(rhs)
-	case 1 then
-		y=callOctave("ifftshift",X);
-	case 2 then
-		y=callOctave("ifftshift",X,DIM);
-	end
-endfunction
\ No newline at end of file
+//Calling Sequence:
+// ifftshift1(x)
+// ifftshift1(x, dim)
+//Parameters:
+//x- It is a vector of N elements corresponding to time samples
+//dim- The optional DIM argument can be used to limit the dimension along which the permutation occurs
+//Description:
+//Undoes the action of the 'fftshift1' function. For 'x' of even length 'fftshift1' is its own inverse, but odd lengths differ slightly.
+//Examples:
+//x = [1, 2, 3, 4];
+//ifftshift1(fftshift1(x));
+//ans =
+//[1, 2, 3, 4];
+
+  funcprot(0);
+  rhs = argn(2);
+  if (rhs < 1 | rhs > 2) then
+    error ("ifftshift1: wrong number of arguments");
+  end
+
+ if (~or(type(x) == [1 5 8 10 4 6]))
+    error ("ifftshitft1: arg1 (x) must be a vector or matrix");
+  end
+
+  if (rhs == 1) then
+    dim = 1:max(size(size(x)));
+  else
+    if (~(isscalar(dim) & dim > 0 & dim == fix(dim))) then
+      error ("ifftshift1: arg2 (dim) must be a positive integer");
+    end
+  end
+
+  for d = dim
+    sz = size(x);
+    sz2 = floor(sz(d) / 2);
+    dim_idx = [sz2+1:sz(d), 1:sz2];
+    if (d == 1) then
+      x = x(dim_idx, :);
+    elseif ( d == max(size(size(x))) ) then
+      x = x(:, dim_idx);
+    else
+      idx = repmat({':'}, 1, max(size(size(x))));
+      idx(d) = {dim_idx};
+      x = x(idx{:});
+    end
+  end
+  y = x;
+
+endfunction
+
+//input validation:
+//assert_checkerror("ifftshift1()", "ifftshift1: wrong number of arguments");
+//assert_checkerror("ifftshift1(1, 2, 3)", "Wrong number of input arguments.");
+//assert_checkerror("ifftshift1(0:2, -1)", "ifftshift1: arg2 (dim) must be a positive integer");
+//assert_checkerror("ifftshift1(0:2, 0:3)", "ifftshift1: arg2 (dim) must be a positive integer");
+
+//test mx1 input:
+//x = [0:7];
+//y = ifftshift1(x);
+//assert_checkequal(y, [4 5 6 7 0 1 2 3]);
+//assert_checkequal(ifftshift1(y), x);
+
+//test 1xm input:
+//x = [0:6]';
+//y = ifftshift1(x);
+//assert_checkequal(y, [3;4;5;6;0;1;2]);
+//assert_checkequal(ifftshift1(y), [6;0;1;2;3;4;5]);
+
+//test mxn input:
+//x = [0:3];
+//x = [x;2*x;3*x+1;4*x+1];
+//y = ifftshift1(x);
+//assert_checkequal(y, [[7 10 1 4];[9 13 1 5];[2 3 0 1];[4 6 0 2]]);
+//assert_checkequal(ifftshift1(y), x);
+
+//test dim is provided:
+//x = [0:3];
+//x = [x;2*x;3*x+1;4*x+1];
+//y = ifftshift1(x, 2);
+//assert_checkequal(y, [[2 3 0 1];[4 6 0 2];[7 10 1 4];[9 13 1 5]]);
+//assert_checkequal(ifftshift1(y, 2), x);
-- 
cgit