logspace2

LOGSPACE Logarithmically spaced vector.
   LOGSPACE(X1, X2) generates a row vector of 50 logarithmically
   equally spaced points between decades 2^X1 and 2^X2.  If X2
   is pi, then the points are between 2^X1 and pi.

   LOGSPACE(X1, X2, N) generates N points.
   For N < 2, LOGSPACE returns 2^X2.

   Class support for inputs X1,X2:
      float: double, single

   See also LINSPACE, :.

0001 function y = logspace(d1, d2, n)
0002 %LOGSPACE Logarithmically spaced vector.
0003 %   LOGSPACE(X1, X2) generates a row vector of 50 logarithmically
0004 %   equally spaced points between decades 2^X1 and 2^X2.  If X2
0005 %   is pi, then the points are between 2^X1 and pi.
0006 %
0007 %   LOGSPACE(X1, X2, N) generates N points.
0008 %   For N < 2, LOGSPACE returns 2^X2.
0009 %
0010 %   Class support for inputs X1,X2:
0011 %      float: double, single
0012 %
0013 %   See also LINSPACE, :.
0014 
0015 %   Copyright 1984-2004 The MathWorks, Inc.
0016 %   $Revision: 5.11.4.1 $  $Date: 2004/07/05 17:01:21 $
0017 %
0018 %   5/31/07 S.T. adapted from logspace.m to fit a log2 curve
0019 
0020 if nargin == 2
0021     n = 50;
0022 end
0023 n = double(n);
0024 
0025 if d2 == pi
0026     d2 = log2(pi);
0027 end
0028 
0029 if d2 == single(pi)   
0030     d2 = log2(single(pi));
0031 end
0032 
0033 y = (2).^ [d1+(0:n-2)*(d2-d1)/(floor(n)-1), d2];