function b=double2bin(n)
%DOUBLE2BIN Convert double precision floating point to binary string.
%   DOUBLE2BIN(N) returns the binary representation of the double precision
%   floating point number N in the form [sign][exponent][mantissa].
%
%   The binary representation of F is computed, not converted from its 
%   hexadecimal representation as in NUM2BIN. 
%
%   See also NUM2BIN, DEC2BIN, BIN2DEC, HEX2DEC, BASE2DEC.

%   Francisco J. Beron-Vera
%   $Revision: 1.3 $  $Date: 2006/08/30 16:19:35 $

% Convert integer part to binary string.
i=abs(fix(n));
ib=[];
while i~=0
   ib=[ib num2str(rem(i,2))];
   i=fix(i/2);
end
if isempty(ib)
   ib=['0'];
end
ib=fliplr(ib);
% Convert fractional part to binary string.
f=abs(n-fix(n));
fb=[];
for j=1:53
   fb=[fb num2str(fix(f*2))];
   f=f*2-fix(f*2);
end
% Output as a string of the form [sign][exponent][mantissa].
if n>0
   s='0';
else
   s='1';
end
if length(ib)==1
   if str2num(ib)==0
      e=[dec2bin(0) dec2bin(1022)];
      m=fb(2:end);
   else
      e=[dec2bin(0) dec2bin(1023)];
      m=fb;
   end
else
   e=dec2bin(length(ib)+1022);
   m=[ib(2:end) fb];
end
b=['[' s '][' e '][' m(1:52) ']'];