I use current(2013/12/12) latest revision of yaml-cpp.
I noticed that both YAML::Load("")
and YAML::Load("---\n...") results in a Null node,
i.e. YAML::Load("").Type() == YAML::NodeType::Null
yet when sent to std::ostream the former outputs an empty string
but the latter outputs tilde (~).
I want both nodes to output an empty string.
How can I achieve it?
I want to do so because I noticed tilde is interpreted as a string when I use YAML::Load.
Here is the code to show this difference.
#include <yaml-cpp/yaml.h>
#include <iostream>
#include <cassert>
int main() {
YAML::Node node1 = YAML::Load("");
YAML::Node node2 = YAML::Load("---\n...");
assert (node1.Type() == YAML::NodeType::Null);
assert (node2.Type() == YAML::NodeType::Null);
std::cout << node1 << std::endl;
std::cout << node2 << std::endl;
}
/* OUTPUT:
~
*/
According to the Github Issue, this behavior was fixed in 2016.
Related
this is my first stackoverflow question, so I hope the following text meets the question requirements. If not, please tell me what needs to be changed so I can adapt the question.
I'm new to CGAL and C++ in general. I would like to use CGAL 5.0.2 on a Macbook Pro early 2015 with macOS Catalina Version 10.15.4.
So to begin with, I followed the instruction steps given by the CGAL documentation using the package manager Homebrew. Since CGAL is a header-only library I configured it using CMake, as is recommended by the documentation.
It all worked out fine, so I went on trying the recommended examples given in the file CGAL-5.0.2.tar.xz, which is provided here. I'm particularly interested in the example Voronoi_Diagram_2.
Using the Terminal I executed the command -DCGAL_DIR=$HOME/CGAL-5.0.2 -DCMAKE_BUILD_TYPE=Release . in the example folder called Voronoi_Diagram_2. Then I executed the command make. All went well, no error messages were prompted. But executing the resulting exec file didn't produce any results.
After some research I managed to modify the code in a way that it prints the values of some variables. Problem seems to be that the input file which contains the line segments for which the voronoi diagramm shall be calculated is not correctly read.
The while loop which I highlighted in the code below by inserting //// signs seems not to be entered. That's why I assume that the variable ifs is empty, even though the input file "data1.svd.cin", which can be found in the folder "data" of the example, wasn't.
Does anyone have an idea for the reasons of this behaviour? Any help is appreciated.
This is the vd_2_point_location_sdg_linf.cpp file included in the example, which I modified:
// standard includes
#include <iostream>
#include <fstream>
#include <cassert>
// includes for defining the Voronoi diagram adaptor
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Segment_Delaunay_graph_Linf_filtered_traits_2.h>
#include <CGAL/Segment_Delaunay_graph_Linf_2.h>
#include <CGAL/Voronoi_diagram_2.h>
#include <CGAL/Segment_Delaunay_graph_adaptation_traits_2.h>
#include <CGAL/Segment_Delaunay_graph_adaptation_policies_2.h>
// typedefs for defining the adaptor
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Segment_Delaunay_graph_Linf_filtered_traits_2<K> Gt;
typedef CGAL::Segment_Delaunay_graph_Linf_2<Gt> DT;
typedef CGAL::Segment_Delaunay_graph_adaptation_traits_2<DT> AT;
typedef CGAL::Segment_Delaunay_graph_degeneracy_removal_policy_2<DT> AP;
typedef CGAL::Voronoi_diagram_2<DT,AT,AP> VD;
// typedef for the result type of the point location
typedef AT::Site_2 Site_2;
typedef AT::Point_2 Point_2;
typedef VD::Locate_result Locate_result;
typedef VD::Vertex_handle Vertex_handle;
typedef VD::Face_handle Face_handle;
typedef VD::Halfedge_handle Halfedge_handle;
typedef VD::Ccb_halfedge_circulator Ccb_halfedge_circulator;
void print_endpoint(Halfedge_handle e, bool is_src) {
std::cout << "\t";
if ( is_src ) {
if ( e->has_source() ) std::cout << e->source()->point() << std::endl;
else std::cout << "point at infinity" << std::endl;
} else {
if ( e->has_target() ) std::cout << e->target()->point() << std::endl;
else std::cout << "point at infinity" << std::endl;
}
}
int main()
{
std::ifstream ifs("data/data1.svd.cin");
assert( ifs );
VD vd;
Site_2 t;
// /////////// Inserted Comment ////////////////////////////////
std::cout << "In the following the insertion from ifs should take place" << std::flush;
// ///////////////// while loop which doesn't seem to be active //////////////////
while ( ifs >> t ) {
// Existing Code to insert the points in the voronoi structure
vd.insert(t);
// Inserted Code to check if while loop is entered
std::cout << "Entered while loop" << std::flush;
}
// ///////////////////////////////////////////////////////////////////////////////
ifs.close();
assert( vd.is_valid() );
std::ifstream ifq("data/queries1.svd.cin");
assert( ifq );
Point_2 p;
while ( ifq >> p ) {
std::cout << "Query point (" << p.x() << "," << p.y()
<< ") lies on a Voronoi " << std::flush;
Locate_result lr = vd.locate(p);
if ( Vertex_handle* v = boost::get<Vertex_handle>(&lr) ) {
std::cout << "vertex." << std::endl;
std::cout << "The Voronoi vertex is:" << std::endl;
std::cout << "\t" << (*v)->point() << std::endl;
} else if ( Halfedge_handle* e = boost::get<Halfedge_handle>(&lr) ) {
std::cout << "edge." << std::endl;
std::cout << "The source and target vertices "
<< "of the Voronoi edge are:" << std::endl;
print_endpoint(*e, true);
print_endpoint(*e, false);
} else if ( Face_handle* f = boost::get<Face_handle>(&lr) ) {
std::cout << "face." << std::endl;
std::cout << "The vertices of the Voronoi face are"
<< " (in counterclockwise order):" << std::endl;
Ccb_halfedge_circulator ec_start = (*f)->ccb();
Ccb_halfedge_circulator ec = ec_start;
do {
print_endpoint(ec, false);
} while ( ++ec != ec_start );
}
std::cout << std::endl;
}
ifq.close();
return 0;
}
I am new to CGAL.
I tried to modify Examples/Arrangement_on_surfaces_2 Bezier_curves.cpp to save arrangement to file as shown below:
//! \file examples/Arrangement_on_surface_2/Bezier_curves.cpp
// Constructing an arrangement of Bezier curves.
#include <fstream>
#include <CGAL/basic.h>
#ifndef CGAL_USE_CORE
#include <iostream>
int main ()
{
std::cout << "Sorry, this example needs CORE ..." << std::endl;
return 0;
}
#else
#include <CGAL/Cartesian.h>
#include <CGAL/CORE_algebraic_number_traits.h>
#include <CGAL/Arr_Bezier_curve_traits_2.h>
#include <CGAL/Arrangement_2.h>
#include <CGAL/IO/Arr_iostream.h>
#include "arr_inexact_construction_segments.h"
#include "arr_print.h"
typedef CGAL::CORE_algebraic_number_traits Nt_traits;
typedef Nt_traits::Rational NT;
typedef Nt_traits::Rational Rational;
typedef Nt_traits::Algebraic Algebraic;
typedef CGAL::Cartesian<Rational> Rat_kernel;
typedef CGAL::Cartesian<Algebraic> Alg_kernel;
typedef Rat_kernel::Point_2 Rat_point_2;
typedef CGAL::Arr_Bezier_curve_traits_2<Rat_kernel, Alg_kernel, Nt_traits>
Traits_2;
typedef Traits_2::Curve_2 Bezier_curve_2;
typedef CGAL::Arrangement_2<Traits_2> Arrangement_2;
//typedef CGAL::Arrangement_2<Traits_2> Arrangement;
int main (int argc, char *argv[])
{
// Get the name of the input file from the command line, or use the default
// Bezier.dat file if no command-line parameters are given.
const char *filename = (argc > 1) ? argv[1] : "Bezier.dat";
const char *outfilename = (argc > 1) ? argv[1] : "BezierOut.dat";
// Open the input file.
std::ifstream in_file (filename);
if (! in_file.is_open()) {
std::cerr << "Failed to open " << filename << std::endl;
return 1;
}
// Read the curves from the input file.
unsigned int n_curves;
std::list<Bezier_curve_2> curves;
Bezier_curve_2 B;
unsigned int k;
in_file >> n_curves;
for (k = 0; k < n_curves; k++) {
// Read the current curve (specified by its control points).
in_file >> B;
curves.push_back (B);
std::cout << "B = {" << B << "}" << std::endl;
}
in_file.close();
// Construct the arrangement.
Arrangement_2 arr;
insert (arr, curves.begin(), curves.end());
// Print the arrangement size.
std::ofstream out_file;
out_file.open(outfilename);
out_file << "The arrangement size:" << std::endl
<< " V = " << arr.number_of_vertices()
<< ", E = " << arr.number_of_edges()
<< ", F = " << arr.number_of_faces() << std::endl;
out_file << arr;
out_file.close();
return 0;
}
#endif
If I comment out the line out_file << arr; it works fine. Otherwise it generates a C2678 error in read_x_monotone_curve in Arr_text_formtter.h
I am using Visual Studio 15 x86.
Thank you for any help.
I solve this by modifying the print_arrangement(arr) routine in arr_print.h to save_arrangement(arr) with a std::ofstream in place of std::cout.
It appears that the << operator does not work.
If someone else has a better solution I am open to it.
Points of intersections in an arrangement of Bezier curves cannot be represented in an exact manner. Therefore, such an arrangement cannot be saved using the default export (<<) operator and the standard format.
The easiest solution is to store the curves, but this means that the arrangement must be recomputed each time the curves are read. Perhaps other solution could be devised, but they are not implemented.
I am using the wcin in order to store a single character in a wchar_t. Then I try to print it with a wcout call and the french character 'é' : but I can't see it at my console.
My compiler is g++ 4.5.4 and my OS is Ubuntu 12.10 64 bits.
Here is my attempt (wideChars.cpp) :
#include <iostream>
int main(){
using namespace std;
wchar_t aChar;
cout << "Enter your char : ";
wcin >> aChar;
wcout << L"You entered " << aChar << L" .\n";
return 0;
}
When I lauch the programm :
$ ./wideChars
Enter your char : é
You entered .
So, what's wrong with this code ?
First, add some error checking. Test what does wcin.good() return after the input and what does wcout.good() return after the "You entered" print? I suspect one of those will return false.
What are your LANG and LC_* environment variables set to?
Then try to fix this by adding this at the top of your main(): wcin.imbue(std::locale("")); wcout.imbue(std::locale(""));
I do not have my Ubuntu at hand right now, so I am flying blind here and mostly guessing.
UPDATE
If the above suggestion does not help then try to construct locale like this and imbue() this locale instead.
std::locale loc (
std::locale (),
new std::codecvt_byname<wchar_t, char, std::mbstate_t>("")));
UPDATE 2
Here is what works for me. The key is to set the C locale as well. IMHO, this is a bug in GNU C++ standard library implementation. Unless I am mistaken, setting std::locale::global(""); should also set the C library locale.
#include <iostream>
#include <locale>
#include <clocale>
#define DUMP(x) do { std::wcerr << #x ": " << x << "\n"; } while (0)
int main(){
using namespace std;
std::locale loc ("");
std::locale::global (loc);
DUMP(std::setlocale(LC_ALL, NULL));
DUMP(std::setlocale(LC_ALL, ""));
wcin.imbue (loc);
DUMP (wcin.good());
wchar_t aChar = 0;
wcin >> aChar;
DUMP (wcin.good());
DUMP ((int)aChar);
wcout << L"You entered " << aChar << L" .\n";
return 0;
}
UPDATE 3
I am confused, now I cannot reproduce it again and setting std::locale::global(loc); seems to do the right thing wrt/ the C locale as well.
So, after spending hours reading and understanding I have finally made my first OpenCL program that actually does something, which is it adds two vectors and outputs to a file.
#include <iostream>
#include <vector>
#include <cstdlib>
#include <string>
#include <fstream>
#define __CL_ENABLE_EXCEPTIONS
#include <CL/cl.hpp>
int main(int argc, char *argv[])
{
try
{
// get platforms, devices and display their info.
std::vector<cl::Platform> platforms;
cl::Platform::get(&platforms);
std::vector<cl::Platform>::iterator i=platforms.begin();
std::cout<<"OpenCL \tPlatform : "<<i->getInfo<CL_PLATFORM_NAME>()<<std::endl;
std::cout<<"\tVendor: "<<i->getInfo<CL_PLATFORM_VENDOR>()<<std::endl;
std::cout<<"\tVersion : "<<i->getInfo<CL_PLATFORM_VERSION>()<<std::endl;
std::cout<<"\tExtensions : "<<i->getInfo<CL_PLATFORM_EXTENSIONS>()<<std::endl;
// get devices
std::vector<cl::Device> devices;
i->getDevices(CL_DEVICE_TYPE_ALL,&devices);
int o=99;
std::cout<<"\n\n";
// iterate over available devices
for(std::vector<cl::Device>::iterator j=devices.begin(); j!=devices.end(); j++)
{
std::cout<<"\tOpenCL\tDevice : " << j->getInfo<CL_DEVICE_NAME>()<<std::endl;
std::cout<<"\t\t Type : " << j->getInfo<CL_DEVICE_TYPE>()<<std::endl;
std::cout<<"\t\t Vendor : " << j->getInfo<CL_DEVICE_VENDOR>()<<std::endl;
std::cout<<"\t\t Driver : " << j->getInfo<CL_DRIVER_VERSION>()<<std::endl;
std::cout<<"\t\t Global Mem : " << j->getInfo<CL_DEVICE_GLOBAL_MEM_SIZE>()/(1024*1024)<<" MBytes"<<std::endl;
std::cout<<"\t\t Local Mem : " << j->getInfo<CL_DEVICE_LOCAL_MEM_SIZE>()/1024<<" KBbytes"<<std::endl;
std::cout<<"\t\t Compute Unit : " << j->getInfo<CL_DEVICE_MAX_COMPUTE_UNITS>()<<std::endl;
std::cout<<"\t\t Clock Rate : " << j->getInfo<CL_DEVICE_MAX_CLOCK_FREQUENCY>()<<" MHz"<<std::endl;
}
std::cout<<"\n\n\n";
//MAIN CODE BEGINS HERE
//get Kernel
std::ifstream ifs("vector_add_kernel.cl");
std::string kernelSource((std::istreambuf_iterator<char>(ifs)), std::istreambuf_iterator<char>());
std::cout<<kernelSource;
//Create context, select device and command queue.
cl::Context context(devices);
cl::Device &device=devices.front();
cl::CommandQueue cmdqueue(context,device);
// Generate Source vector and push the kernel source in it.
cl::Program::Sources sourceCode;
sourceCode.push_back(std::make_pair(kernelSource.c_str(), kernelSource.size()));
//Generate program using sourceCode
cl::Program program=cl::Program(context, sourceCode);
//Build program..
try
{
program.build(devices);
}
catch(cl::Error &err)
{
std::cerr<<"Building failed, "<<err.what()<<"("<<err.err()<<")"
<<"\nRetrieving build log"
<<"\n Build Log Follows \n"
<<program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(devices.front());
}
//Declare and initialize vectors
std::vector<cl_float>B(993448,1.3);
std::vector<cl_float>C(993448,1.3);
std::vector<cl_float>A(993448,1.3);
cl_int N=A.size();
//Declare and intialize proper work group size and global size. Global size raised to the nearest multiple of workGroupSize.
int workGroupSize=128;
int GlobalSize;
if(N%workGroupSize) GlobalSize=N - N%workGroupSize + workGroupSize;
else GlobalSize=N;
//Declare buffers.
cl::Buffer vecA(context, CL_MEM_READ_WRITE, sizeof(cl_float)*N);
cl::Buffer vecB(context, CL_MEM_READ_ONLY , (B.size())*sizeof(cl_float));
cl::Buffer vecC(context, CL_MEM_READ_ONLY , (C.size())*sizeof(cl_float));
//Write vectors into buffers
cmdqueue.enqueueWriteBuffer(vecB, 0, 0, (B.size())*sizeof(cl_float), &B[0] );
cmdqueue.enqueueWriteBuffer(vecB, 0, 0, (C.size())*sizeof(cl_float), &C[0] );
//Executing kernel
cl::Kernel kernel(program, "vector_add");
cl::KernelFunctor kernel_func=kernel.bind(cmdqueue, cl::NDRange(GlobalSize), cl::NDRange(workGroupSize));
kernel_func(vecA, vecB, vecC, N);
//Reading back values into vector A
cmdqueue.enqueueReadBuffer(vecA,true,0,N*sizeof(cl_float), &A[0]);
cmdqueue.finish();
//Saving into file.
std::ofstream output("vectorAdd.txt");
for(int i=0;i<N;i++) output<<A[i]<<"\n";
}
catch(cl::Error& err)
{
std::cerr << "OpenCL error: " << err.what() << "(" << err.err() <<
")" << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
The problem is, for smaller values of N, I'm getting the correct result that is 2.6
But for larger values, like the one in the code above (993448) I get garbage output varying between 1 and 2.4.
Here is the Kernel code :
__kernel void vector_add(__global float *A, __global float *B, __global float *C, int N) {
// Get the index of the current element
int i = get_global_id(0);
//Do the operation
if(i<N) A[i] = C[i] + B[i];
}
UPDATE : Ok it seems the code is working now. I have fixed a few minor mistakes in my code above
1) The part where GlobalSize is initialized has been fixed.
2)Stupid mistake in enqueueWriteBuffer (wrong parameters given)
It is now outputting the correct result for large values of N.
Try to change the data type from float to double etc.
I want to parse scalar as bool.
This example works:
#include <yaml.h>
#include <iostream>
#include <sstream>
#include <string>
void operator>> (const YAML::Node & node, bool & b)
{
std::string tmp;
node >> tmp;
std::cout << tmp << std::endl;
b = (tmp == "1") || (tmp == "yes");
}
int main()
{
bool b1, b2;
std::stringstream ss("key: да\notherkey: no");
YAML::Parser parser(ss);
YAML::Node doc;
parser.GetNextDocument(doc);
doc["key"] >> b1;
doc["otherkey"] >> b2;
std::cout << b1 << std::endl;
std::cout << b2 << std::endl;
return 0;
}
But in more complicated case template operator is used:
YAML::operator>><bool> (node=..., value=#0x63f6e8) at /usr/include/yaml-cpp/nodeimpl.h:24
And I get 'YAML::InvalidScalar' if string in not 'yes' or 'no'.
yaml-cpp already reads bools by default, as specified by the YAML spec.
y, yes, true, on
produce true, and
n, no, false, off
produce false. If you want to extend or change this behavior (for example, so that "да" also produces true), as you found out, overloading operator >> in the YAML namespace works.
The reason it needs to be in the YAML namespace (but only for "more complicated examples" - meaning where you don't directly call operator >> with a bool argument) is the way C++ lookup works.
See this answer to my old question for a great explanation.