I'm new in Omnetpp and I am using it to study queueing with the help of inet framework.
In this I need to have a function that repeat a string n-times. I'm searching it but I'm not finding.
For this reason I'm trying to implement it in omnetpp 5.6.2. I defined it in
Omnetpp-5.6.2\src\sim\nedfunctions.cc adding this code:
cNedValue nedf_repeatstr(cComponent *contextComponent, cNedValue argv[], int argc) {
std::string s = argv[0].stdstringValue();
std::string s1 = argv[0].stdstringValue();
int n = argv[1];
for (int i=1; i<n;i++)
s += s1;
return s; } Define_NED_Function(ned_repeatstr, "string repeatstr(string s, int n)");
But when I play the omnepp.ini it say "define_ned_function() or define_ned_math_function() missing from c++?"
Where am I wrong?
Can some one help me?
Related
std::XXX::inerator always support operator+, such as
const string s = "abcdef";
cout << *(s.begin() + 3);//output d
But ptree doesn't support operator+.
ptree p = root.get_child("insert");
//I want to directly goto the 3rd child.
auto iter = p.begin()+3;//error
I know I can use a for loop to do this. But I wonder if there is a more grace way to do this?
I achieved this by:
template <class InputIterator, class Distance>
void advance (InputIterator& it, Distance n);
C++ stl advance document
auto iter = p.begin();
advance(iter, 3);
first of all I admit I'm a newbie in C++ addons for node.js.
I'm writing my first addon and I reached a good result: the addon does what I want. I copied from various examples I found in internet to exchange complex data between the two languages, but I understood almost nothing of what I wrote.
The first thing scaring me is that I wrote nothing that seems to free some memory; another thing which is seriously worrying me is that I don't know if what I wrote may helps or creating confusion for the V8 garbage collector; by the way I don't know if there are better ways to do what I did (iterating over js Object keys in C++, creating js Objects in C++, creating Strings in C++ to be used as properties of js Objects and what else wrong you can find in my code).
So, before going on with my job writing the real math of my addon, I would like to share with the community the nan and V8 part of it to ask if you see something wrong or that can be done in a better way.
Thank you everybody for your help,
iCC
#include <map>
#include <nan.h>
using v8::Array;
using v8::Function;
using v8::FunctionTemplate;
using v8::Local;
using v8::Number;
using v8::Object;
using v8::Value;
using v8::String;
using Nan::AsyncQueueWorker;
using Nan::AsyncWorker;
using Nan::Callback;
using Nan::GetFunction;
using Nan::HandleScope;
using Nan::New;
using Nan::Null;
using Nan::Set;
using Nan::To;
using namespace std;
class Data {
public:
int dt1;
int dt2;
int dt3;
int dt4;
};
class Result {
public:
int x1;
int x2;
};
class Stats {
public:
int stat1;
int stat2;
};
typedef map<int, Data> DataSet;
typedef map<int, DataSet> DataMap;
typedef map<float, Result> ResultSet;
typedef map<int, ResultSet> ResultMap;
class MyAddOn: public AsyncWorker {
private:
DataMap *datas;
ResultMap results;
Stats stats;
public:
MyAddOn(Callback *callback, DataMap *set): AsyncWorker(callback), datas(set) {}
~MyAddOn() { delete datas; }
void Execute () {
for(DataMap::iterator i = datas->begin(); i != datas->end(); ++i) {
int res = i->first;
DataSet *datas = &i->second;
for(DataSet::iterator l = datas->begin(); l != datas->end(); ++l) {
int dt4 = l->first;
Data *data = &l->second;
// TODO: real population of stats and result
}
// test result population
results[res][res].x1 = res;
results[res][res].x2 = res;
}
// test stats population
stats.stat1 = 23;
stats.stat2 = 42;
}
void HandleOKCallback () {
Local<Object> obj;
Local<Object> res = New<Object>();
Local<Array> rslt = New<Array>();
Local<Object> sts = New<Object>();
Local<String> x1K = New<String>("x1").ToLocalChecked();
Local<String> x2K = New<String>("x2").ToLocalChecked();
uint32_t idx = 0;
for(ResultMap::iterator i = results.begin(); i != results.end(); ++i) {
ResultSet *set = &i->second;
for(ResultSet::iterator l = set->begin(); l != set->end(); ++l) {
Result *result = &l->second;
// is it ok to declare obj just once outside the cycles?
obj = New<Object>();
// is it ok to use same x1K and x2K instances for all objects?
Set(obj, x1K, New<Number>(result->x1));
Set(obj, x2K, New<Number>(result->x2));
Set(rslt, idx++, obj);
}
}
Set(sts, New<String>("stat1").ToLocalChecked(), New<Number>(stats.stat1));
Set(sts, New<String>("stat2").ToLocalChecked(), New<Number>(stats.stat2));
Set(res, New<String>("result").ToLocalChecked(), rslt);
Set(res, New<String>("stats" ).ToLocalChecked(), sts);
Local<Value> argv[] = { Null(), res };
callback->Call(2, argv);
}
};
NAN_METHOD(AddOn) {
Local<Object> datas = info[0].As<Object>();
Callback *callback = new Callback(info[1].As<Function>());
Local<Array> props = datas->GetOwnPropertyNames();
Local<String> dt1K = Nan::New("dt1").ToLocalChecked();
Local<String> dt2K = Nan::New("dt2").ToLocalChecked();
Local<String> dt3K = Nan::New("dt3").ToLocalChecked();
Local<Array> props2;
Local<Value> key;
Local<Object> value;
Local<Object> data;
DataMap *set = new DataMap();
int res;
int dt4;
DataSet *dts;
Data *dt;
for(uint32_t i = 0; i < props->Length(); i++) {
// is it ok to declare key, value, props2 and res just once outside the cycle?
key = props->Get(i);
value = datas->Get(key)->ToObject();
props2 = value->GetOwnPropertyNames();
res = To<int>(key).FromJust();
dts = &((*set)[res]);
for(uint32_t l = 0; l < props2->Length(); l++) {
// is it ok to declare key, data and dt4 just once outside the cycles?
key = props2->Get(l);
data = value->Get(key)->ToObject();
dt4 = To<int>(key).FromJust();
dt = &((*dts)[dt4]);
int dt1 = To<int>(data->Get(dt1K)).FromJust();
int dt2 = To<int>(data->Get(dt2K)).FromJust();
int dt3 = To<int>(data->Get(dt3K)).FromJust();
dt->dt1 = dt1;
dt->dt2 = dt2;
dt->dt3 = dt3;
dt->dt4 = dt4;
}
}
AsyncQueueWorker(new MyAddOn(callback, set));
}
NAN_MODULE_INIT(Init) {
Set(target, New<String>("myaddon").ToLocalChecked(), GetFunction(New<FunctionTemplate>(AddOn)).ToLocalChecked());
}
NODE_MODULE(myaddon, Init)
One year and half later...
If somebody is interested, my server is up and running since my question and the amount of memory it requires is stable.
I can't say if the code I wrote really does not has some memory leak or if lost memory is freed at each thread execution end, but if you are afraid as I was, I can say that using same structure and calls does not cause any real problem.
You do actually free up some of the memory you use, with the line of code:
~MyAddOn() { delete datas; }
In essence, C++ memory management boils down to always calling delete for every object created by new. There are also many additional architecture-specific and legacy 'C' memory management functions, but it is not strictly necessary to use these when you do not require the performance benefits.
As an example of what could potentially be a memory leak: You're passing the object held in the *callback pointer to the function AsyncQueueWorker. Yet nowhere in your code is this pointer freed, so unless the Queue worker frees it for you, there is a memory leak here.
You can use a memory tool such as valgrind to test your program further. It will spot most memory problems for you and comes highly recommended.
One thing I've observed is that you often ask (paraphrased):
Is it okay to declare X outside my loop?
To which the answer actually is that declaring variables inside of your loops is better, whenever you can do it. Declare variables as deep inside as you can, unless you have to re-use them. Variables are restricted in scope to the outermost set of {} brackets. You can read more about this in this question.
is it ok to use same x1K and x2K instances for all objects?
In essence, when you do this, if one of these objects modifies its 'x1K' string, then it will change for all of them. The advantage is that you free up memory. If the string is the same for all these objects anyway, instead of having to store say 1,000,000 copies of it, your computer will only keep a single one in memory and have 1,000,000 pointers to it instead. If the string is 9 ASCII characters long or longer under amd64, then that amounts to significant memory savings.
By the way, if you don't intend to modify a variable after its declaration, you can declare it as const, a keyword short for constant which forces the compiler to check that your variable is not modified after declaration. You may have to deal with quite a few compiler errors about functions accepting only non-const versions of things they don't modify, some of which may not be your own code, in which case you're out of luck. Being as conservative as possible with non-const variables can help spot problems.
I populate a very large array using a stxxl::VECTOR_GENERATOR<MyData>::result::bufwriter_type (something like 100M entries) which I need to sort in parallel.
I use the stxxl::sort(vector->begin(), vector->end(), cmp(), memoryAmount) method, which in theory should do what I need: sort the elements very efficiently.
However, during the execution of this method I noticed that only one processor is fully utilised, and all the other cores are quite idle (I suspect there is little activity to fetch the input, but in practice they don't do anything).
This is my question: is it possible to exploit more cores during the sorting phase, or is the parallelism used only to fetch the input asynchronously? If so, are there documents that explain how to enable it? (I looked extensively the documentation on the website, but I couldn't find anything).
Thanks very much!
EDIT
Thanks for the suggestion. I provide below some more information.
First of all I use MacOs for my experiments. What I do is that I launch the following program and I study its behaviour.
typedef struct Triple {
long t1, t2, t3;
Triple(long s, long p, long o) {
this->t1 = s;
this->t2 = p;
this->t3 = o;
}
Triple() {
t1 = t2 = t3 = 0;
}
} Triple;
const Triple minv(std::numeric_limits<long>::min(),
std::numeric_limits<long>::min(), std::numeric_limits<long>::min());
const Triple maxv(std::numeric_limits<long>::max(),
std::numeric_limits<long>::max(), std::numeric_limits<long>::max());
struct cmp: std::less<Triple> {
bool operator ()(const Triple& a, const Triple& b) const {
if (a.t1 < b.t1) {
return true;
} else if (a.t1 == b.t1) {
if (a.t2 < b.t2) {
return true;
} else if (a.t2 == b.t2) {
return a.t3 < b.t3;
}
}
return false;
}
Triple min_value() const {
return minv;
}
Triple max_value() const {
return maxv;
}
};
typedef stxxl::VECTOR_GENERATOR<Triple>::result vector_type;
int main(int argc, const char** argv) {
vector_type vector;
vector_type::bufwriter_type writer(vector);
for (int i = 0; i < 1000000000; ++i) {
if (i % 10000000 == 0)
std::cout << "Inserting element " << i << std::endl;
Triple t;
t.t1 = rand();
t.t2 = rand();
t.t3 = rand();
writer << t;
}
writer.finish();
//Sort the vector
stxxl::sort(vector.begin(), vector.end(), cmp(), 1024*1024*1024);
std::cout << vector.size() << std::endl;
}
Indeed there seems to be only one or maximum two threads working during the execution of this program. Notice that the machine has only a single disk.
Can you please confirm me whether the parallelism work on macos? If not, then I will try to use linux to see what happens. Or is perhaps because there is only one disk?
In principle what you are doing should work out-of-the-box. With everything working you should see all cores doing processing.
Since it doesnt work, we'll have to find the error, and debugging why we see no parallel speedups is still tricky business these days.
The main idea is to go from small to large examples:
what platform is this? There is no parallelism on MSVC, only on Linux/gcc.
By default STXXL builds on Linux/gcc with USE_GNU_PARALLEL. you can turn it off to see if it has an effect.
Try reproducing the example values shown in http://stxxl.sourceforge.net/tags/master/stxxl_tool.html - with and without USE_GNU_PARALLEL
See if just in memory parallel sorting scales on your processor/system.
Deep in the sauce here. I haven't worked with time to much so I'm a little confused here. I know there is FILETIME and SYSTEMTIME. What I am trying to get at this point (because it might change) are file that are less than a 20 seconds old. This returning the files and their size and something in seconds, What I'd like to know is where it is filtering by time if it is, and how can I adjust it to suit my needs. Thank you.
using namespace std;
typedef vector<WIN32_FIND_DATA> tFoundFilesVector;
std::wstring LastWriteTime;
int getFileList(wstring filespec, tFoundFilesVector &foundFiles)
{
WIN32_FIND_DATA findData;
HANDLE h;
int validResult=true;
int numFoundFiles = 0;
h = FindFirstFile(filespec.c_str(), &findData);
if (h == INVALID_HANDLE_VALUE)
return 0;
while (validResult)
{
numFoundFiles++;
foundFiles.push_back(findData);
validResult = FindNextFile(h, &findData);
}
return numFoundFiles;
}
void showFileAge(tFoundFilesVector &fileList)
{
unsigned _int64 fileTime, curTime, age;
tFoundFilesVector::iterator iter;
FILETIME ftNow;
//__int64 nFileSize;
//LARGE_INTEGER li;
//li.LowPart = ftNow.dwLowDateTime;
//li.HighPart = ftNow.dwHighDateTime;
CoFileTimeNow(&ftNow);
curTime = ((_int64) ftNow.dwHighDateTime << 32) + ftNow.dwLowDateTime;
for (iter=fileList.begin(); iter<fileList.end(); iter++)
{
fileTime = ((_int64)iter->ftLastWriteTime.dwHighDateTime << 32) + iter->ftLastWriteTime.dwLowDateTime;
age = curTime - fileTime;
cout << "FILE: '" << iter->cFileName << "', AGE: " << (_int64)age/10000000UL << " seconds" << endl;
}
}
int main()
{
string fileSpec = "*.*";
tFoundFilesVector foundFiles;
tFoundFilesVector::iterator iter;
int foundCount = 0;
getFileList(L"c:\\Mapper\\*.txt", foundFiles);
getFileList(L"c:\\Mapper\\*.jpg", foundFiles);
foundCount = foundFiles.size();
if (foundCount)
{
cout << "Found "<<foundCount<<" matching files.\n";
showFileAge(foundFiles);
}
system("pause");
return 0;
}
I don't know what you've done to try to debug this but your code doesn't work at all. The reason is you're passing getFileList() a wstring but then passing that to the ANSI version of FindFirstFile(). Unless you #define UNICODE or use the appropriate compiler option, all system calls will expect char *, not UNICODE.
The easiest fix is to simply change the declaration of getFileList() to this:
int getFileList(const char * filespec, tFoundFilesVector &foundFiles)
Change the call to FindFirstFile() to this:
h = FindFirstFile((LPCSTR)filespec, &findData);
And then change the calls to it to this:
getFileList("c:\\Mapper\\*.txt", foundFiles);
getFileList("c:\\Mapper\\*.jpg", foundFiles);
Your other option is to switch all char strings to wide chars, but either way you need to be consistent throughout. Once you do that the program works as expected.
As for your final question, your program is not filtering by time at all.
Not quite an answer, but you might want to read about file system tunneling.
It may prevent you from what you're trying to do in some situations.
I have a C++ code that I am trying to interface with Matlab. My mex file runs fine in the first run but crashes in the second run. However, if I clear all the variables in the Matlab before execution (using clear all) program never crashes. So I have a question in this:
1. Can mex function takes variables from the Matlab workspace without using some special functions? Am I doing it somehow in my code, unintentionally?
I have a posted the mex function that I wrote. It has a one dimensional vector called "block" that is read inside the C++ function called sphere_detector. For the present problem the block size is 1x1920 and it is read in the chunk of 16 elements inside the sphere_detector. Program crashed when I read the SECOND chunk of 16 elements. The first element that I read in the chunk will throw this error:
First-chance exception at 0x000007fefac7206f (sphere_decoder.mexw64) in MATLAB.exe: 0xC0000005: Access violation reading location 0xffffffffffffffff.
MATLAB.exe has triggered a breakpoint
I checked my block vector, it should have all the values initialized and it has that. So, I am little confused as to why I am facing this problem.
I am using Matlab 2010a and Visual Studio 2010 Professional.
Here is the mex function:
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
double *mod_scheme, *Mt, *Mr, *block_length, *SNR;
mod_scheme = mxGetPr(prhs[0]);
Mt = mxGetPr(prhs[1]);
Mr = mxGetPr(prhs[2]);
block_length = mxGetPr(prhs[3]);
SNR = mxGetPr(prhs[4]);
/* Now take the input block. This is an encoded block and sphere detector will do the transmission too -- I can change it later */
double *block = mxGetPr(prhs[5]);
double *LIST_SIZE = mxGetPr(prhs[6]);
double **cand_sym;
int a = *mod_scheme;
int b = *Mt;
int c = *Mr;
int d = *block_length;
int e = *SNR;
int f = *LIST_SIZE;
int bitSize = (int)(log10(1.0*a)/log10(2.0));
for(int i=0; i<(int)*block_length; ++i)
{
printf("%d\n", (int)block[i]);
}
printf("Hello world %d %d %d %d %d!\n", (int)*mod_scheme, (int)*Mt, (int)*Mr, (int)*block_length, (int)*SNR);
/* Inputs are read correctly now set the outputs */
double *llr, *cand_dist;
/* for llrs */
plhs[0] = mxCreateDoubleMatrix(1, d, mxREAL);
llr = mxGetPr(plhs[0]);
/* for cand_dist */
int no_mimo_sym = d/(b*bitSize);
plhs[1] = mxCreateDoubleMatrix(1, f*no_mimo_sym, mxREAL);
cand_dist = mxGetPr(plhs[1]);
/* for cand_syms */
plhs[2] = mxCreateDoubleMatrix(b*bitSize*no_mimo_sym, f,mxREAL); //transposed version
double *candi;
candi = mxGetPr(plhs[2]);
cand_sym = (double**)mxMalloc(f*sizeof(double*));
if(cand_sym != NULL)
{
for(int i=0;i<f; ++i)
{
cand_sym[i] = candi + i*b*bitSize*no_mimo_sym;
}
}
sphere_decoder(a,b,c,d,e,block,f,llr,cand_dist,cand_sym);
// mxFree(cand_sym);
}
The portion inside the sphere decoder code where I get read exception looks like this:
for(int _block_length=0;_block_length<block_length; _block_length+=Mt*bitSize)
{
printf("Transmitting MIMO Symbol: %d\n", _block_length/(Mt*bitSize));
for(int _antenna = 0; _antenna < Mt; ++_antenna)
for(int _tx_part=0;_tx_part<bitSize; _tx_part++)
{
// PROGRAM CRASHES EXECUTING THIS LINE
bitstream[_antenna][_tx_part] = (int)block_data[_block_length + _antenna*bitSize + _tx_part];
}
............................REST OF THE CODE..................
}
Any help would be appreciated.
With regards,
Newbie
Well I finally managed to solve the problem. It was a very stupid mistake that I made. I had a pointer to a pointer(double *a;) of data type double and by mistake I assigned it memory of integer (I ran a find and replace command where I changed lots of int to double but this one left). Hence heap was getting corrupted. Also I changed my Mex function where I created dynamic variables using calloc and passed them to the C++ function. Once C++ function returned I copied there values to matlab variables and freed them usind free().