I have the following test code trying to read file into a list
open('raw250-split1.pl', read, Stream),
read(Stream,train_xs(TrainXs)),
length(TrainXs, MaxTrain).
I will omit part of the output due to the file is quite large.
It works well with yap,
➜ chill git:(master) ✗ yap [18/06/19| 5:48PM]
% Restoring file /usr/lib/Yap/startup.yss
YAP 6.2.2 (x86_64-linux): Sat Sep 17 13:59:03 UTC 2016
?- open('raw250-split1.pl', read, Stream),
read(Stream, train_xs(TrainXs)),
length(TrainXs, MaxTrain).
MaxTrain = 225,
Stream = '$stream'(3),
TrainXs = [[parse([which,rivers,run,through,states,bordering,new,mexico,/],answer(_A,(river(_A),traverse(_A,_B),next_to(_B,_C),const(_C,stateid('new mexico')))))],
<omited output>
,[parse([what,is,the,largest,state,capital,in,population,?],answer(_ST,largest(_SU,(capital(_ST),population(_ST,_SU)))))]]
But on swi-prolog, it will produce Type error
➜ chill git:(master) ✗ swipl [18/06/19| 7:24PM]
Welcome to SWI-Prolog (threaded, 64 bits, version 7.6.4)
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.
Please run ?- license. for legal details.
For online help and background, visit http://www.swi-prolog.org
For built-in help, use ?- help(Topic). or ?- apropos(Word).
?- open('raw250-split1.pl', read, Stream),
read(Stream, train_xs(TrainXs)),
length(TrainXs, MaxTrain).
ERROR: raw250-split1.pl:4:
Type error: `list' expected, found `parse(which.(rivers.(run.(through.(states.(bordering.(new.(mexico.((/).[])))))))),
<omited output>
,answer(_67604,(state(_67604),next_to(_67604,_67628),const(_67628,stateid(kentucky))))).[].(parse(what.((is).(the.(largest.(state.(capital.(in.(population.((?).[])))))))),answer(_67714,largest(_67720,(capital(_67714),population(_67714,_67720))))).[].[]))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))' (a compound)
In:
[10] throw(error(type_error(list,...),context(...,_67800)))
[7] <user>
Note: some frames are missing due to last-call optimization.
Re-run your program in debug mode (:- debug.) to get more detail.
What might be the problem for the error here?
File raw250-split1.pl can be found from the ftp url below, if you'd like to try it.
Thank you for the help!
I am trying to migrate an earlier code to SWI-Prolog, which was written in
SICStus 3 #3: Thu Sep 12 09:54:27 CDT 1996 or earlier
by Raymond J. Mooney ftp://ftp.cs.utexas.edu/pub/mooney/chill/.
All the questions with this tag are all related to this task. I'm new to prolog, helps and suggestions are welcomed!
The raw250-split1.pl was apparently written using canonical notation. The traditional list functor is ./2 but SWI-Prolog 7.x changed it to '[|]'/2 in order to use ./2 for other purposes. This results in the the variable TrainXs being instantiated by the read/2 call to a compound term whose argument is not a list:
?- open('raw250-split1.pl', read, Stream), read(Stream,train_xs(TrainXs)).
Stream = <stream>(0x7f8975e08e90),
TrainXs = parse(which.(rivers.(run.(through.(states.(bordering.(... . ...)))))), answer(_94, (river(_94), traverse(_94, _100), next_to(_100, _106), const(_106, stateid('new mexico'))))).[].(parse(what.((is).(the.(highest.(point.(... . ...))))), answer(_206, (high_point(_204, _206), const(_204, stateid(montana))))).[].(parse(what.((is).(the.(most.(... . ...)))), answer(_298, largest(_300, (population(_298, _300), state(...), ..., ...)))).[].(parse(through.(which.(states.(... . ...))), answer(_414, (state(_414), const(..., ...), traverse(..., ...)))).[].(parse(what.((is).(... . ...)), answer(_500, longest(_500, river(...)))).[].(parse(how.(... . ...), answer(_566, (..., ...))).[].(parse(... . ..., answer(..., ...)).[].(parse(..., ...).[].(... . ... .(... . ...))))))))).
YAP still uses the ./2 functor for lists, which explains why it can handle it. A workaround for SWI-Prolog is to start it with the --traditional command-line option:
$ swipl --traditional
...
?- open('raw250-split1.pl', read, Stream), read(Stream,train_xs(TrainXs)).
Stream = <stream>(0x7faeb2f77700),
TrainXs = [[parse([which, rivers, run, through, states, bordering|...], answer(_94, (river(_94), traverse(_94, _100), next_to(_100, _106), const(_106, stateid('new mexico')))))], [parse([what, is, the, highest, point|...], answer(_206, (high_point(_204, _206), const(_204, stateid(montana)))))], [parse([what, is, the, most|...], answer(_298, largest(_300, (population(_298, _300), state(...), ..., ...))))], [parse([through, which, states|...], answer(_414, (state(_414), const(..., ...), traverse(..., ...))))], [parse([what, is|...], answer(_500, longest(_500, river(...))))], [parse([how|...], answer(_566, (..., ...)))], [parse([...|...], answer(..., ...))], [parse(..., ...)], [...]|...].
The type error you get is due to the length/2 expecting a list when the first argument is bound.
There is a tilde as last character in that file, causing the syntax being invalid, so you should remove it before reading. I don't know why YAP accept the file as valid, should raise an error AFAIK.
There is a read option dotlists/2 in SWI-Prolog:
dotlists(Bool)
If true (default false), read .(a,[]) as a
list, even if lists are internally nor constructed
using the dot as functor. This is primarily intended
to read the output from write_canonical/1 from
other Prolog systems. See section 5.1.
http://www.swi-prolog.org/pldoc/man?predicate=read_term/2
This gives you the desired result, without changing the mode:
Welcome to SWI-Prolog (threaded, 64 bits, version 8.1.0)
?- read_term(X, [dotlists(true)]).
|: .(a,.(b,.(c,[]))).
X = [a, b, c].
I am working on Pintos OS project. I get this message:
Page fault at 0xbfffefe0: not present error writing page in user context.
The problem with Pintos OS project is that it won't simply tell the line and method that caused the exception.
I know how to use breakpoints/watchpoints etc. but is there any way to step right to it without going through the WHOLE flow and ALL OS files line by line so that I could jump into line that caused exception and put breakpoint there? I looked at GDB commands but didn't find anything.
When I debug this project I have to step through the whole program until I find that error/exception which is very time consuming. There is probably a faster way to do this.
Thanks.
Whole trace:
nestilll#vdebian:~/Class/pintos/proj-3-bhling-nestilll-nsren/src/vm/build$ pintos -v -k -T 60 --qemu --gdb --filesys-size=2 -p tests/vm/pt-grow-pusha -a pt-grow-pusha --swap-size=4 -- -q -f run pt-grow-pusha
Use of literal control characters in variable names is deprecated at /home/nestilll/Class/pintos/src/utils/pintos line 909.
Prototype mismatch: sub main::SIGVTALRM () vs none at /home/nestilll/Class/pintos/src/utils/pintos line 933.
Constant subroutine SIGVTALRM redefined at /home/nestilll/Class/pintos/src/utils/pintos line 925.
warning: disabling timeout with --gdb
Copying tests/vm/pt-grow-pusha to scratch partition...
qemu -hda /tmp/N2JbACdqyV.dsk -m 4 -net none -nographic -s -S
PiLo hda1
Loading............
Kernel command line: -q -f extract run pt-grow-pusha
Pintos booting with 4,088 kB RAM...
382 pages available in kernel pool.
382 pages available in user pool.
Calibrating timer... 419,020,800 loops/s.
hda: 13,104 sectors (6 MB), model "QM00001", serial "QEMU HARDDISK"
hda1: 205 sectors (102 kB), Pintos OS kernel (20)
hda2: 4,096 sectors (2 MB), Pintos file system (21)
hda3: 98 sectors (49 kB), Pintos scratch (22)
hda4: 8,192 sectors (4 MB), Pintos swap (23)
filesys: using hda2
scratch: using hda3
swap: using hda4
Formatting file system...done.
Boot complete.
Extracting ustar archive from scratch device into file system...
Putting 'pt-grow-pusha' into the file system...
Erasing ustar archive...
Executing 'pt-grow-pusha':
(pt-grow-pusha) begin
Page fault at 0xbfffefe0: not present error writing page in user context.
pt-grow-pusha: dying due to interrupt 0x0e (#PF Page-Fault Exception).
Interrupt 0x0e (#PF Page-Fault Exception) at eip=0x804809c
cr2=bfffefe0 error=00000006
eax=bfffff8c ebx=00000000 ecx=0000000e edx=00000027
esi=00000000 edi=00000000 esp=bffff000 ebp=bfffffa8
cs=001b ds=0023 es=0023 ss=0023
pt-grow-pusha: exit(-1)
Execution of 'pt-grow-pusha' complete.
Timer: 71 ticks
Thread: 0 idle ticks, 63 kernel ticks, 8 user ticks
hda2 (filesys): 62 reads, 200 writes
hda3 (scratch): 97 reads, 2 writes
hda4 (swap): 0 reads, 0 writes
Console: 1359 characters output
Keyboard: 0 keys pressed
Exception: 1 page faults
Powering off...
to have the GDB debugger run and stop at the desired location:
gdb filename <--start debug session
br main <--set a breakpoint at the first line of the main() function
r <--run until that breakpoint is reached
br filename.c:linenumber <--set another breakpoint at the desired line of code
c <--continue until second breakpoint is encuntered
The debugger will stop at the desired location in the file, IF it ever actually gets there,
When I debug this project I have to step through the whole program
until I find what caused error/exception which is very time consuming.
There is probably a faster way to do this.
Normally what you would do is set a breakpoint just before the error. Then your program will run at full speed, without your intervention, until it reaches that point.
There are several wrinkles here.
First, sometimes it is difficult to know where to put the breakpoint. In this case I suppose I would look for the code that is printing the message, then work backward from there. Sometimes you have to stop at the failure point, examine the stack, set a new breakpoint further up, and re-run the program.
Then there is the mechanics of setting the breakpoint. One simple way is to break by function name, like break my_function. Another is to use the file name and line number, like break my_file.c:73.
Finally, sometimes a breakpoint can be hit many times before the failure is seen. You can use ignore counts (see help ignore) or conditional breakpoints (like break my_function if variable = 27) to limit the number of stops.
I want to try the LDA -c code by Blie .et.al. as it is in this link.
I have compiled the code, and when I run ./lda in my terminal, the following result is displayed.
usage : lda est [initial alpha] [k] [settings] [data] [random/seeded/manual=filename/*] [directory]
lda inf [settings] [model] [data] [name]
Which means that, it has been complied correctly.
However, in spite reading the README.txt file there, I am not being able to succesfully run the LDA code.
Either it says Segmentation fault (core dumped) or killed.
What am I missing? How to use it on the example data they have given?
I have read the stack overflow answer to the question asked here, but it was not useful as I dont know the default values.
P.S: I am a beginer.
Are you using ap.txt instead of ap.dat by any chance? lda-c doesn't take raw sentences or marked up data as input; it takes a sequence of bag of words information for each document. When ap.dat has a line like
186 0:1 6144:1 3586:2 ..., it means that the corresponding document has 186 distinct words, word 0 appears once, word 6144 appears once, word 3586 appears twice, and so on.
This command works for me (using Blei's original code):
./lda est 0.1 10 settings.txt ap.dat random modeldir
(Feel free to tweak the initial alpha (0.1) and number of topics (10) as you wish.)
I have written some C code that takes an mp4 file with h264-encoded video and AAC-encoded audio and writes it to segmented .ts files.
The code can be seen here: http://pastebin.com/JVdgjM9G
The problem is that the code chokes on audio packets. Because I am converting from h264, I have to use the "h264_mp4toannexb" which I finally got working for video frames. However, as soon as the program reaches the first audio packet (stream 1 below) it crashes.
Sample output:
Output #0, mpegts, to 'testvideo':
Stream #0.0: Video: libx264, yuv420p, 1280x720, q=2-31, 1416 kb/s, 90k tbn, 23.98 tbc
Stream #0.1: Audio: libfaac, 48000 Hz, stereo, 127 kb/s
First chunk: testvideo-00001.ts
Read frame, keyframe: 1, index: 0
Did bitfilter fun!
Read frame, keyframe: 0, index: 0
Did bitfilter fun!
(...this repeats several more times, truncated for space...)
Did bitfilter fun!
Read frame, keyframe: 0, index: 0
Did bitfilter fun!
Read frame, keyframe: 1, index: 1
base(54516) malloc: *** error for object 0x7fd2db404520: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
Abort trap: 6
I tried changing the code to also run the filter on the audio stream (using audio_stream->codec instead of video_stream->codec), but that simply just gives an error from the filter.
The problem happens when I try to call av_interleaved_write_frame(output_context, &packet);- for the filtered video packets, there is no problem but the audio packet it completely chokes on. I am kind of stumped on why though, so any help is appreciated.
It turns out the av_free_packet call after the bitfilter manipulation was actually releasing the video packets. Removing that call caused the code to run correctly!