J.S. Leon's webpage
Goals
- Fix up Leon's code for modern use.
Progress
- Fixed several issues relating to outdated design.
- Originally defaulted to using short's: now uses unsigned's.
- Changed obsolete CLK_TCK to CLOCKS_PER_SEC.
- Discovered a serious fencepost error in loops.
- Temporary solution: allocate one more memory spot than necessary to allow Leon's indexing
- Long term: correct all of Leon's loops to index properly.
- Discovered undocumented restriction on Cayley library names: no hyphens.
Solutions to known bugs
- Related to reading the input file:
./wtdist huffman-code4.gap 6 huffman-matrix4 // seems to work, creates huffman-matrix4 file ./desauto -code huffman-code4.gap huffman-matrix4 huffman-autgp4 // does not work output: Error: Library block huffman-matrix4 not found in specified library. Program was executing function read01Matrix (line 234 in file ../../src/leon/src/readdes.c).
- Related files:
- SOLUTION: Cayley library format does not support names with hyphens. Use only alphanumeric and underscore characters.
- Bus Errors
./wtdist example1::left 4 really Bus error
- Related file:
- Happens on OS X, but not Linux- it is due to invalid memory access.
- SOLUTION: see above, regarding "fencepost error."
Known Bugs in Leon
- Running out of memory:
- W. C. Huffman describes a general procedure to produce examples of this bug:
The main problem always seems to be when there are only a few minimal weight codewords. I think you can create a lot of examples that will make it difficult in the following way: Let C1 be any code you want with minimum weight at least 3. Let C2 be the [2,1,2] code with basis [1 1]. Form the direct sum of C1 and C2. This will create a code of minimum weight 2 with only one codeword of minimum weight 2. I have a feeling this will give you trouble even if the code C1 has an automorphism group that is easy to compute.
- The following codes, as noted by Huffman, commonly cause an out of memory condition. Even if this doesn't happen, they are still good benchmarks for memory use:
Example 1: 1111111111110000000000001100000000 0000000000001010100000000010101011 0000000000000101010000000001010111 0000000000000000001010100000001110 0000000000000000000101010000001101 0000001010101010100000001000100000 0000000101010101010000000100010000 1010100000001010100000001010000000 0101010000000101010000000101000000 0010100000000010100011110000000000 0001010000000001010011110000000000 1000100000001000101100110000000000 0100010000000100011100110000000000 0000000010100011110010100000000000 0000000001010011110001010000000000 0000001000101100111000100000000000 0000000100011100110100010000000000 Example 2: 1111111111110000000000001100000000 0000000000001010100000000010101011 0000000000000101010000000001010111 0000000000000000001010100000001110 0000000000000000000101010000001101 0000001010101010100000001000100000 0000000101010101010000000100010000 1010100000001010100000001010000000 0101010000000101010000000101000000 0010100000000010100011110000000000 0001010000000001010011110000000000 1000100000001000101100110000000000 0100010000000100011100110000000000 0000000010100011110001010000000000 0000000001010011110010100000000000 0000001000101100110100010000000000 0000000100011100111000100000000000 Example 3: 1111111111110000000000001100000000 0000000000000000001111110010101010 0000000000000000001111110001010101 0000000000001010101010100000000011 0000000000000101010101010000000011 0000001010100000000000001000101000 0000000101010000000000000100010100 1010100000000000000000001010001000 0101010000000000000000000101000100 0010100000000010100011110000000000 0001010000000001010011110000000000 1000100000001000101100110000000000 0100010000000100011100110000000000 0000000010100011110010100000000000 0000000001010011110001010000000000 0000001000101100111000100000000000 0000000100011100110100010000000000 Example 4: 1111111111110000000000001100000000 0000000000000000001111110010101010 0000000000000000001111110001010101 0000000000001010101010100000000011 0000000000000101010101010000000011 0000001010100000000000001000101000 0000000101010000000000000100010100 1010100000000000000000001010001000 0101010000000000000000000101000100 0010100000000001010011110000000000 0001010000000010100011110000000000 1000100000000100011100110000000000 0100010000001000101100110000000000 0000000010100011110001010000000000 0000000001010011110010100000000000 0000001000101100110100010000000000 0000000100011100111000100000000000
- W. C. Huffman describes a general procedure to produce examples of this bug:
- Infinite Hangs (?)
- These have not yet been tested...
checking equivalence of: [1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] [0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] [0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1] [0 0 1 1 1 1 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1] ----------------------------------------------------------------- [1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] [0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] [0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1] [0 0 1 1 0 0 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1] checking equivalence of: [1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] [0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] [0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] [0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1] ----------------------------------------------------------------- [1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] [0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] [0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] [0 0 1 1 0 0 1 1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1]
- This example also leads to an infinite loop in computeSubgroup...
./wtdist huffman-code4.gap 6 huffman_matrix4 // now works, using underscores ./desauto -code huffman-code4.gap huffman_matrix4 huffman_autgp4 // fall into infinite loop
- Related files:
- These have not yet been tested...