code changes by Sonu Sharma during FOSSEE Fellowship 2018

1 files changed, 67 insertions, 0 deletions

diff --git a/macros/digitrevorder.sci b/macros/digitrevorder.sci
new file mode 100644
index 0000000..886c43f
--- /dev/null
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+// Returns input data in digit-reversed order
+
+// Calling Sequence
+//[y,i] = digitrevorder(x,r)
+//y = digitrevorder(x,r)
+
+// Parameters
+//x: Vector of real or complex values
+//r: radix / base
+//y: input vector in digit reverse order
+//i: indices
+
+// Description
+//This function returns the input data after reversing the digits of the indices and reordering the elements of the input array.
+
+// Examples
+//x = [%i,1,3,6*%i] ;
+//r = 2 ;
+//[y i]=digitrevorder(x, r)
+//Output :
+// i  =
+//
+//    1.    3.    2.    4.
+// y  =
+//
+//    i      3.    1.    6.i
+function [y, i] = digitrevorder (x, r)
+    funcprot(0);
+    [nargout, nargin] = argn() ;
+
+  if (nargin > 2 | nargin <= 1)
+    error("digitrevorder : invalid number of inputs")
+  elseif (~ isvector (x))
+    error ("digitrevorder : X must be a vector");
+  elseif (~ (isscalar (r) & r == fix (r) & r >= 2 & r <= 36))
+    error ("digitrevorder : R must be an integer between 2 and 36");
+  else
+    tmp = log (length(x)) / log (r);
+    if (fix (tmp) ~= tmp)
+      error ("digitrevorder: X must have length equal to an integer power of radix");
+    end
+  end
+
+  old_ind = 0:length(x) - 1;
+
+  //new_ind = base2dec(mtlb_fliplr(dec2base(old_ind, r)), r); //it works only on octave
+  old_ind_base = dec2base(old_ind, r) ;
+  new_ind_base = [] ;
+  b = [] ;
+  for i=1:length(x)
+      new_ind_base = [new_ind_base mtlb_fliplr(old_ind_base(i))];
+  end
+  new_ind = base2dec(new_ind_base,r) ;
+  //end of index conversion
+
+  i = new_ind + 1;
+  y(old_ind + 1) = x(i);
+
+  [rows_x columns_x] = size(x) ;
+
+  if (columns_x == 1)
+    y = y';
+  else
+    i = i;
+  end
+
+endfunction