Check nvidia card video memory usage on linux

nvidia-smi

GCC C++ Linker errors: Undefined reference to 'vtable for XXX', Undefined reference to 'ClassName::ClassName()'

(From Stack Overflow)
 Answer:

Assuming those methods are in one of the libs it looks like an ordering problem.
When linking libraries into an executable they are done in the order they are declared.
Also the linker will only take the methods/functions required to resolve currently oustanding dependencies. If a subsequent library then uses methods/functions that were not originally required by the objects you will have missing dependencies.
How it works:

• Take all the object files and combine them into an executable
• Resolve any dependecies among object files.
• Foreach library in order:
  • Check unresolved dependencies and see if the lib resolves them.
  • If so load required part into the executable.

Example:
Objects requires:

• Open
• Close
• BatchRead
• BatchWrite

Lib 1 provides:

• Open
• Close
• read
• write

Lib 2 provides

• BatchRead (but uses lib1:read)
• BatchWrite (but uses lib1:write)

If linked like this:

gcc -o plop plop.o -l1 -l2

Then the linker will fail to resolve the read and write symbols.
But if I linki the application like this:

gcc -o plop plop.o -l2 -l1

Then it will link correctly. As l2 resolves the BatchRead and BatchWrite dependencies but also adds two new ones (read and write). When we link with l1 next all four dependencies are resolved.

Recursively Delete .svn Directories

find . -type d -name .svn -exec rm -rf {} \;

Patch metis-4.0 error: conflicting types for __log2

Origin post found here: http://leembong.blogspot.com/2012/02/how-to-patch-metis-40-error-conflicting.html#!/2012/02/how-to-patch-metis-40-error-conflicting.html


METIS is a set of serial programs for partitioning graphs, partitioning finite element meshes, and producing fill reducing orderings for sparse matrices. The algorithms implemented in METIS are based on the multilevel recursive-bisection, multilevel k-way, and multi-constraint partitioning schemes. I give a patch for metis-4.0 software, compilation fails with gcc 4.4.x

make a patch file:
--------------------- metis-4.0.patch--------------------

diff -rupN metis-4.0/Lib/kmetis.c metis-4.0.NEW/Lib/kmetis.c
--- metis-4.0/Lib/kmetis.c 1998-11-30 17:26:47.000000000 +0100
+++ metis-4.0.NEW/Lib/kmetis.c 2010-04-29 17:49:55.000000000 +0200
@@ -66,7 +66,7 @@ void METIS_WPartGraphKway(int *nvtxs, id
     ctrl.dbglvl = options[OPTION_DBGLVL];
   }
   ctrl.optype = OP_KMETIS;
-  ctrl.CoarsenTo = amax((*nvtxs)/(40*log2(*nparts)), 20*(*nparts));
+  ctrl.CoarsenTo = amax((*nvtxs)/(40*log2_function(*nparts)), 20*(*nparts));
   ctrl.maxvwgt = 1.5*((graph.vwgt ? idxsum(*nvtxs, graph.vwgt) : (*nvtxs))/ctrl.CoarsenTo);
 
   InitRandom(-1);
diff -rupN metis-4.0/Lib/kvmetis.c metis-4.0.NEW/Lib/kvmetis.c
--- metis-4.0/Lib/kvmetis.c 1998-11-30 17:26:47.000000000 +0100
+++ metis-4.0.NEW/Lib/kvmetis.c 2010-04-29 17:49:55.000000000 +0200
@@ -66,7 +66,7 @@ void METIS_WPartGraphVKway(int *nvtxs, i
     ctrl.dbglvl = options[OPTION_DBGLVL];
   }
   ctrl.optype = OP_KVMETIS;
-  ctrl.CoarsenTo = amax((*nvtxs)/(40*log2(*nparts)), 20*(*nparts));
+  ctrl.CoarsenTo = amax((*nvtxs)/(40*log2_function(*nparts)), 20*(*nparts));
   ctrl.maxvwgt = 1.5*((graph.vwgt ? idxsum(*nvtxs, graph.vwgt) : (*nvtxs))/ctrl.CoarsenTo);
 
   InitRandom(-1);
diff -rupN metis-4.0/Lib/mkmetis.c metis-4.0.NEW/Lib/mkmetis.c
--- metis-4.0/Lib/mkmetis.c 1998-11-30 17:26:48.000000000 +0100
+++ metis-4.0.NEW/Lib/mkmetis.c 2010-04-29 17:49:55.000000000 +0200
@@ -47,7 +47,7 @@ void METIS_mCPartGraphKway(int *nvtxs, i
     ctrl.dbglvl = options[OPTION_DBGLVL];
   }
   ctrl.optype = OP_KMETIS;
-  ctrl.CoarsenTo = amax((*nvtxs)/(20*log2(*nparts)), 30*(*nparts));
+  ctrl.CoarsenTo = amax((*nvtxs)/(20*log2_function(*nparts)), 30*(*nparts));
 
   ctrl.nmaxvwgt = 1.5/(1.0*ctrl.CoarsenTo);
 
diff -rupN metis-4.0/Lib/proto.h metis-4.0.NEW/Lib/proto.h
--- metis-4.0/Lib/proto.h 1998-11-30 17:26:50.000000000 +0100
+++ metis-4.0.NEW/Lib/proto.h 2010-04-29 17:49:55.000000000 +0200
@@ -459,7 +459,7 @@ double drand48();
 void srand48(long);
 int ispow2(int);
 void InitRandom(int);
-int log2(int);
+int log2_function(int);
 
 
 
diff -rupN metis-4.0/Lib/rename.h metis-4.0.NEW/Lib/rename.h
--- metis-4.0/Lib/rename.h 1998-11-30 17:26:50.000000000 +0100
+++ metis-4.0.NEW/Lib/rename.h 2010-04-29 17:49:55.000000000 +0200
@@ -410,7 +410,8 @@
 #define RandomPermute   __RandomPermute
 #define ispow2    __ispow2
 #define InitRandom   __InitRandom
-#define log2    __log2
+/* Correction bug Nadir SOUALEM*/
+#define log2_function    __log2_function
 
 
 
diff -rupN metis-4.0/Lib/util.c metis-4.0.NEW/Lib/util.c
--- metis-4.0/Lib/util.c 1998-11-30 17:26:50.000000000 +0100
+++ metis-4.0.NEW/Lib/util.c 2010-04-29 17:49:55.000000000 +0200
@@ -507,9 +507,9 @@ void InitRandom(int seed)
 }
 
 /*************************************************************************
-* This function returns the log2(x)
+* This function returns the log2_function(x)
 **************************************************************************/
-int log2(int a)
+int log2_function(int a)
 {
   int i; 

---------------------------------------------------------------------- 

command:

nsoualem@gold: -> cd metis-4.0
nsoualem@gold: -> patch -p1 < metis-4.0.patch

CUDA: unspecified launch failure

"An unspecified launch failure is almost always a segfault."

Compile Boost with cxx flags

sh ./bootstrap.sh
sudo ./b2 install --build-type=complete --layout=tagged cxxflags=-fPIC

Switching GCC version

aptitude install gcc-4.4 g++-4.4
update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.4 10
update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.4 10

Bug due to inherentance

1. Derived class call base class function A which call base class's other functions B
The program will go to derived class if B is reimplemented.

Debug MPI

For small number of processes

Valgrind
mpiexec -n 8 valgrind --log-file=valgrind-%p.txt <program and args>


Xterm+GDB
mpiexec -np 3 xterm -e gdb <program to debug without args>
in GDB r <args Here>

Install lastest nvidia driver on ubuntu

sudo apt-add-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
sudo apt-get install nvidia-current