The custom stopping criterion creation example.
This example depends on simple-solver, minimal-cuda-solver.
Introduction
About the example
The commented program
#include <ginkgo/ginkgo.hpp>
#include <fstream>
#include <iostream>
#include <map>
#include <string>
#include <thread>
/ **
* The ByInteraction class is a criterion which asks for user input to stop
* the iteration process. Using this criterion is slightly more complex than the
* other ones, because it is asynchronous therefore requires the use of threads.
* /
class ByInteraction
public:
{
/ **
* Boolean set by the user to stop the iteration process
* /
stop_iteration_process, nullptr);
};
GKO_ENABLE_CRITERION_FACTORY(ByInteraction, parameters, Factory);
protected:
bool check_impl(
gko::uint8 stoppingId,
bool setFinalized,
bool* one_changed, const Criterion::Updater&) override
{
bool result = *(parameters_.stop_iteration_process);
if (result) {
this->set_all_statuses(stoppingId, setFinalized, stop_status);
*one_changed = true;
}
}
explicit ByInteraction(std::shared_ptr<const gko::Executor> exec)
: EnablePolymorphicObject<ByInteraction, Criterion>(std::move(exec))
{}
: EnablePolymorphicObject<ByInteraction, Criterion>(
parameters_{
factory->get_parameters()}
{}
};
void run_solver(volatile bool* stop_iteration_process,
std::shared_ptr<gko::Executor> exec)
{
This mixin inherits from (a subclass of) PolymorphicObject and provides a base implementation of a ne...
Definition polymorphic_object.hpp:691
An array is a container which encapsulates fixed-sized arrays, stored on the Executor tied to the arr...
Definition array.hpp:187
The Criterion class is a base class for all stopping criteria.
Definition criterion.hpp:64
#define GKO_CREATE_FACTORY_PARAMETERS(_parameters_name, _factory_name)
This Macro will generate a new type containing the parameters for the factory _factory_name.
Definition abstract_factory.hpp:308
#define GKO_FACTORY_PARAMETER_SCALAR(_name, _default)
Creates a scalar factory parameter in the factory parameters structure.
Definition abstract_factory.hpp:473
#define GKO_ENABLE_BUILD_METHOD(_factory_name)
Defines a build method for the factory, simplifying its construction by removing the repetitive typin...
Definition abstract_factory.hpp:422
@ factory
LinOpFactory events.
The Ginkgo namespace.
Definition abstract_factory.hpp:48
constexpr T one()
Returns the multiplicative identity for T.
Definition math.hpp:803
std::uint8_t uint8
8-bit unsigned integral type.
Definition types.hpp:149
This struct is used to pass parameters to the EnableDefaultCriterionFactoryCriterionFactory::generate...
Definition criterion.hpp:233
Some shortcuts
using ValueType = double;
using IndexType = int;
CSR is a matrix format which stores only the nonzero coefficients by compressing each row of the matr...
Definition csr.hpp:146
Dense is a matrix format which explicitly stores all values of the matrix.
Definition dense.hpp:136
BiCGSTAB or the Bi-Conjugate Gradient-Stabilized is a Krylov subspace solver.
Definition bicgstab.hpp:82
typename detail::remove_complex_s< T >::type remove_complex
Obtain the type which removed the complex of complex/scalar type or the template parameter of class b...
Definition math.hpp:354
Read Data
Create solver factory and solve system
auto solver =
bicg::build()
.with_criteria(ByInteraction::build().with_stop_iteration_process(
stop_iteration_process))
.on(exec)
->generate(A);
gko::log::Logger::iteration_complete_mask, std::cout, true));
solver->apply(b, x);
std::cout << "Solver stopped" << std::endl;
Stream is a Logger which logs every event to a stream.
Definition stream.hpp:59
Print solution
std::cout << "Solution (x): \n";
write(std::cout, x);
Calculate residual
A->apply(one, x, neg_one, b);
b->compute_norm2(res);
std::cout << "Residual norm sqrt(r^T r): \n";
}
int main(int argc, char* argv[])
{
void write(StreamType &&os, MatrixPtrType &&matrix, layout_type layout=detail::mtx_io_traits< std::remove_cv_t< detail::pointee< MatrixPtrType > > >::default_layout)
Writes a matrix into an output stream in matrix market format.
Definition mtx_io.hpp:324
Print version information
static const version_info & get()
Returns an instance of version_info.
Definition version.hpp:168
Figure out where to run the code
if (argc == 2 && (std::string(argv[1]) == "--help")) {
std::cerr << "Usage: " << argv[0] << " [executor]" << std::endl;
std::exit(-1);
}
Figure out where to run the code
const auto executor_string = argc >= 2 ? argv[1] : "reference";
Figure out where to run the code
std::map<std::string, std::function<std::shared_ptr<gko::Executor>()>>
exec_map{
{"cuda",
[] {
}},
{"hip",
[] {
}},
{"dpcpp",
[] {
}},
{"reference", [] { return gko::ReferenceExecutor::create(); }}};
static std::shared_ptr< CudaExecutor > create(int device_id, std::shared_ptr< Executor > master, bool device_reset, allocation_mode alloc_mode=default_cuda_alloc_mode, CUstream_st *stream=nullptr)
Creates a new CudaExecutor.
static std::shared_ptr< DpcppExecutor > create(int device_id, std::shared_ptr< Executor > master, std::string device_type="all", dpcpp_queue_property property=dpcpp_queue_property::in_order)
Creates a new DpcppExecutor.
static std::shared_ptr< HipExecutor > create(int device_id, std::shared_ptr< Executor > master, bool device_reset, allocation_mode alloc_mode=default_hip_alloc_mode, CUstream_st *stream=nullptr)
Creates a new HipExecutor.
static std::shared_ptr< OmpExecutor > create(std::shared_ptr< CpuAllocatorBase > alloc=std::make_shared< CpuAllocator >())
Creates a new OmpExecutor.
Definition executor.hpp:1373
executor where Ginkgo will perform the computation
const auto exec = exec_map.at(executor_string)();
Declare a user controlled boolean for the iteration process
volatile bool stop_iteration_process{};
Create a new a thread to launch the solver
std::thread t(run_solver, &stop_iteration_process, exec);
Look for an input command "stop" in the console, which sets the boolean to true
std::cout << "Type 'stop' to stop the iteration process" << std::endl;
std::string command;
while (std::cin >> command) {
if (command == "stop") {
break;
} else {
std::cout << "Unknown command" << std::endl;
}
}
std::cout << "User input command 'stop' - The solver will stop!"
<< std::endl;
stop_iteration_process = true;
t.join();
}
Results
This is the expected output:
.
.
.
.
.
.
5.17803e-164
-7.6865e-165
-2.06149e-164
-4.84737e-165
-3.36597e-164
2.22353e-164
1.47594e-165
-1.78592e-165
-6.17274e-166
-3.02681e-166
7.82009e-166
8.57102e-165
-1.28879e-164
-2.62076e-165
2.55329e-165
-5.95988e-166
-5.79273e-166
-5.20172e-166
-6.79458e-166
]
User input command 'stop' - The solver will stop
0.252218
0.108645
0.0662811
0.0630433
0.0384088
0.0396536
0.0402648
0.0338935
0.0193098
0.0234653
0.0211499
0.0196413
0.0199151
0.0181674
0.0162722
0.0150714
0.0107016
0.0121141
0.0123025
]
Solver stopped
Solution (x):
%%MatrixMarket matrix array real general
19 1
0.252218
0.108645
0.0662811
0.0630433
0.0384088
0.0396536
0.0402648
0.0338935
0.0193098
0.0234653
0.0211499
0.0196413
0.0199151
0.0181674
0.0162722
0.0150714
0.0107016
0.0121141
0.0123025
Residual norm sqrt(r^T r):
%%MatrixMarket matrix array real general
1 1
6.50306e-16
Definition lin_op.hpp:146
Comments about programming and debugging
The plain program
#include <ginkgo/ginkgo.hpp>
#include <fstream>
#include <iostream>
#include <map>
#include <string>
#include <thread>
class ByInteraction
public:
{
stop_iteration_process, nullptr);
};
GKO_ENABLE_CRITERION_FACTORY(ByInteraction, parameters, Factory);
protected:
bool check_impl(
gko::uint8 stoppingId,
bool setFinalized,
bool* one_changed, const Criterion::Updater&) override
{
bool result = *(parameters_.stop_iteration_process);
if (result) {
this->set_all_statuses(stoppingId, setFinalized, stop_status);
*one_changed = true;
}
}
explicit ByInteraction(std::shared_ptr<const gko::Executor> exec)
: EnablePolymorphicObject<ByInteraction, Criterion>(std::move(exec))
{}
: EnablePolymorphicObject<ByInteraction, Criterion>(
parameters_{
factory->get_parameters()}
{}
};
void run_solver(volatile bool* stop_iteration_process,
std::shared_ptr<gko::Executor> exec)
{
using ValueType = double;
using IndexType = int;
bicg::build()
.with_criteria(ByInteraction::build().with_stop_iteration_process(
stop_iteration_process))
.on(exec)
->generate(A);
gko::log::Logger::iteration_complete_mask, std::cout, true));
std::cout << "Solver stopped" << std::endl;
std::cout << "Solution (x): \n";
A->apply(one, x, neg_one, b);
b->compute_norm2(res);
std::cout << "Residual norm sqrt(r^T r): \n";
}
int main(int argc, char* argv[])
{
if (argc == 2 && (std::string(argv[1]) == "--help")) {
std::cerr << "Usage: " << argv[0] << " [executor]" << std::endl;
std::exit(-1);
}
const auto executor_string = argc >= 2 ? argv[1] : "reference";
std::map<std::string, std::function<std::shared_ptr<gko::Executor>()>>
exec_map{
{"cuda",
[] {
}},
{"hip",
[] {
}},
{"dpcpp",
[] {
}},
{"reference", [] { return gko::ReferenceExecutor::create(); }}};
const auto exec = exec_map.at(executor_string)();
volatile bool stop_iteration_process{};
std::thread t(run_solver, &stop_iteration_process, exec);
std::cout << "Type 'stop' to stop the iteration process" << std::endl;
std::string command;
while (std::cin >> command) {
if (command == "stop") {
break;
} else {
std::cout << "Unknown command" << std::endl;
}
}
std::cout << "User input command 'stop' - The solver will stop!"
<< std::endl;
stop_iteration_process = true;
t.join();
}
detail::shared_type< OwningPointer > share(OwningPointer &&p)
Marks the object pointed to by p as shared.
Definition utils_helper.hpp:254