Hi John,
Sure, here is the code to demonstrate the problem:
---------------------------------------------------------------------------------------------
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <bitvector.h>
int main(int argc, char *argv[]) {
ibis::bitvector bv;
ibis::bitvector bv2;
bv2.setBit(0,1);
bv2.print(std::cout);
for(int i = 0; i < 315; i++)
{
bv.setBit(i, 0);
}
bv.setBit(315,1);
bv.print(std::cout);
bv = bv2;
bv.print(std::cout);
}
______________________________________________________
The output of this is:
This bitvector stores 0 bits of a 1-bit (1 set) sequence in a 0-word array
and one bit in the active word
0 1 1 2 2 3
0123456789012345678901234567890
-------------------------------
40000000 1
This bitvector stores 310 bits of a 316-bit (1 set) sequence in a 1-word
array and 6 bits in the active word
0 1 1 2 2 3
0123456789012345678901234567890
-------------------------------
0 8000000a 310*0
02000000 000001
This bitvector stores 310 bits of a 311-bit (1 set) sequence in a 1-word
array and one bit in the active word
0 1 1 2 2 3
0123456789012345678901234567890
-------------------------------
0 8000000a 310*0
40000000 1
--------------------------------------------------------------------------------------------------------
Note that bv still has 310 0's out front when it should just be a single
1....
Hope that helps,
I fixed it by calling clear on bv before reassigning it.... Perhaps clear
should be called inside the "=" operator.
If you need anything else, let me know.....
Cheers,
Teryl
On Tue, Mar 20, 2012 at 7:20 PM, K. John Wu <[email protected]> wrote:
> Hi, Teryl,
>
> Thanks for your patience. I imagine that you have a small test
> program that demonstrate this little problem. Would you mind sharing
> it with us? It would save me some trouble of recreate it.
>
> Thanks.
>
> John
>
>
>
> On 3/19/12 1:19 PM, Teryl Taylor wrote:
> > Okay, looks like I found the problem. The problem isn't with
> > adjustSize, it's with the bitvector "=" operator. I had the
> > following setup similar to this:
> >
> > bitvector bitv = "0000000000000000000000000000000000"
> > bitvector bitv2 = "1";
> >
> > I did a
> > bitv = bitv2
> >
> > and expected bitv = "1"
> > but it actually was bitv = "0000000000000000000000000000000001"
> >
> > So that screwed up the |= operation further down.
> >
> > The work around I used to solve this was to clear bitv before
> > assigning bitv2.
> >
> > bitv.clear();
> > bitv = bitv2;
> >
> > now bitv = "1"
> >
> >
> > Not sure if that is the intended usage of "=".
> >
> > Thanks John!
> >
> > Take Care,
> >
> > Teryl
> >
> >
> >
> >
> >
> > On Mon, Mar 19, 2012 at 2:56 PM, Teryl Taylor <[email protected]
> > <mailto:[email protected]>> wrote:
> >
> > Hi John,
> >
> > So looking into this a little more, it looks like appendFill (used
> > by adjustSize) pushes the existing bitmap over and fills in the
> > LSBs. So if I have a bitmap with 1 at the zero element, and I
> > adust the size, to 10, the 1 gets pushed to over 10. Was this the
> > intended functionality of the function? I'm looking for something
> > that will leave the 1 in it's same location and put the zeros on
> > the other side of it. Is there an easy way to do that?
> >
> > Best Regards,
> >
> > Teryl
> >
> >
> > On Mon, Mar 19, 2012 at 12:40 PM, Teryl Taylor
> > <[email protected] <mailto:[email protected]>> wrote:
> >
> > Hi John,
> >
> > It looks like the adjustSize is the problem. If I call
> > adjustsSize(0, 316) on the vector, it prepends the zeros to
> > the front of the bitvector instead of appending the zeros to
> > the end of the bitvector.
> >
> > Is that the intended functionality of adjustSize?
> >
> > Cheers,
> >
> > Teryl
> >
> >
> >
> >
> > On Fri, Mar 16, 2012 at 2:13 PM, K. John Wu <[email protected]
> > <mailto:[email protected]>> wrote:
> >
> > Hi, Teryl,
> >
> > Looks like the code for handling tow bitvectors with
> > differing sizes
> > has some bugs in it. I will look into the problem. In
> > the mean time,
> > simply making sure the two bitvectors represents the same
> > number of
> > bits should give the desired answer. The function to use
> > to make sure
> > the shorter one has the same number of bits as the longer
> > one is
> > ibis::bitvector::adjustSize. This function takes two
> > arguments, it
> > will fill the bitvector with 1s until the position given
> > by the first
> > argument and then fill the remaining positions with 0s
> > until the
> > second argument.
> >
> > Good luck.
> >
> > John
> >
> > PS: The documentation of ibis::bitvector::adjustSize is
> > available
> > online at
> >
> >
> http://lbl.gov/~kwu/fastbit/doc/html/classibis_1_1bitvector.html#a96d95020682574405a91ac6dfed1da69
> > <
> http://lbl.gov/%7Ekwu/fastbit/doc/html/classibis_1_1bitvector.html#a96d95020682574405a91ac6dfed1da69
> >
> >
> >
> >
> > On 3/16/12 9:31 AM, Teryl Taylor wrote:
> > > Hi John,
> > >
> > > I hope all is going well! I'm playing around with the
> > > ibis::bitvector API and I'm seeing some peculiar
> > behavior. I'm
> > > trying to AND two bitmaps of different sizes
> > together.... The first
> > > bitmap looks as follows:
> > >
> > >
> > >
> > >
> >
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > -----------------------------------------------------------
> > >
> > > This bitvector stores 0 bits of a 1-bit (1 set) sequence
> > in a 0-word
> > > array and one bit in the active word
> > > 0 1 1 2 2 3
> > > 0123456789012345678901234567890
> > > -------------------------------
> > > 40000000 1
> > > -----------------------------------------------------------
> > >
> > >
> > >
> >
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > It has one set bit, and that is the zeroth bit in the
> > bitmap. It is
> > > basically one 32 bit literal.
> > >
> > >
> > > I want to And it with the following bitmap which is 326
> > bits long
> > > which is basically all 1's.
> > >
> > >
> > >
> >
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > >
> > > This bitvector stores 310 bits of a 326-bit (326 set)
> > sequence in a
> > > 1-word array and 16 bits in the active word
> > > 0 1 1 2 2 3
> > > 0123456789012345678901234567890
> > > -------------------------------
> > > 0 c000000a 310*1
> > > 7fff8000 1111111111111111
> > >
> > >
> > >
> >
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > >
> > > Now, the first bitmap, should match with the first bit
> > of the second
> > > bitmap (so, basically the first bitmap should be seen as
> > 326 bits
> > > long...with the first bit being set to 1, and the rest
> > zeros). So
> > > when I AND the two together, I want the result to be a
> > bitvector with
> > > the first bit set to one, and the following 325 bits all
> > set to zero.
> > >
> > >
> > > But what I'm seeing is the following result:
> > >
> > >
> >
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > >
> > > This bitvector stores 310 bits of a 326-bit (1 set)
> > sequence in a
> > > 1-word array and 16 bits in the active word
> > > 0 1 1 2 2 3
> > > 0123456789012345678901234567890
> > > -------------------------------
> > > 0 8000000a 310*0
> > > 40000000 1000000000000000
> > >
> > >
> >
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > Which has 310 0's before the one bit is set.... I'm
> > using the &=
> > > operator to do operation. so it goes smallBitmap &=
> > bigBitmap.
> > >
> > >
> > > Is there an easy way to get the answer I am looking for?
> > Or am I
> > > using the bitvectors incorrectly?
> > >
> > >
> > > Best Regards,
> > >
> > >
> > > Teryl
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > FastBit-users mailing list
> > > [email protected]
> > <mailto:[email protected]>
> > >
> >
> https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
> >
> >
> >
> >
>
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