--- /dev/null
+/* Copyright (c) 2017-2018. The SimGrid Team. All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "xbt/log.h"
+#include <simgrid/s4u.hpp>
+
+XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_engine_filtering, "Messages specific for this s4u example");
+
+namespace filter {
+class FrequencyChanged {
+ std::map<simgrid::s4u::Host*, int> host_list;
+
+public:
+ FrequencyChanged(simgrid::s4u::Engine& e) {
+ std::vector<simgrid::s4u::Host*> list = e.get_all_hosts();
+ for (auto& host : list) {
+ host_list.insert({host, host->get_pstate()});
+ }
+ }
+
+ bool operator()(simgrid::s4u::Host* host) { return host->get_pstate() != host_list.at(host); }
+
+ double get_old_speed(simgrid::s4u::Host* host) { return host_list.at(host); }
+};
+class SingleCore {
+public:
+ bool operator()(simgrid::s4u::Host* host) { return host->get_core_count() == 1; }
+};
+
+bool filter_speed_more_than_50Mf(simgrid::s4u::Host* host);
+bool filter_speed_more_than_50Mf(simgrid::s4u::Host* host)
+{
+ return host->getSpeed() > 50E6;
+}
+}
+int main(int argc, char* argv[])
+{
+ simgrid::s4u::Engine e(&argc, argv);
+ e.load_platform(argv[1]);
+
+ /**
+ * Use a lambda function to filter hosts: We only want multicore hosts
+ */
+ XBT_INFO("Hosts currently registered with this engine: %lu", e.get_host_count());
+ std::vector<simgrid::s4u::Host*> list =
+ e.get_filtered_hosts([](simgrid::s4u::Host* host) { return host->get_core_count() > 1; });
+
+ for (auto& host : list)
+ XBT_INFO("The following hosts have more than one core: %s", host->get_cname());
+
+ xbt_assert(list.size() == 1);
+
+ /*
+ * Use a function object (functor) without memory
+ */
+ list = e.get_filtered_hosts(filter::SingleCore());
+
+ for (auto& host : list)
+ XBT_INFO("The following hosts are SingleCore: %s", host->get_cname());
+
+ /**
+ * This just shows how to use a function object that uses
+ * memory to filter.
+ */
+ XBT_INFO("A simple example: Let's retrieve all hosts that changed their frequency");
+ filter::FrequencyChanged filter(e);
+ e.host_by_name("MyHost2")->set_pstate(2);
+ list = e.get_filtered_hosts(filter);
+
+ for (auto& host : list)
+ XBT_INFO("The following hosts changed their frequency: %s (from %.1ff to %.1ff)", host->get_cname(), host->getPstateSpeed(filter.get_old_speed(host)), host->getSpeed());
+
+ /*
+ * You can also just use any normal function (namespaced as well, if you want) to filter
+ */
+ list = e.get_filtered_hosts(filter::filter_speed_more_than_50Mf);
+
+ for (auto& host : list)
+ XBT_INFO("The following hosts have a frequency > 50Mf: %s", host->get_cname());
+
+ return 0;
+}
--- /dev/null
+#!/usr/bin/env tesh
+
+p Let's filter some hosts...
+$ ${bindir:=.}/s4u-engine-filtering$EXEEXT ${platfdir}/energy_platform.xml "--log=root.fmt:[%10.6r]%e(%i:%P@%h)%e%m%n" --cfg=network/model:CM02 --cfg=network/crosstraffic:no
+> [ 0.000000] (0:maestro@) Configuration change: Set 'network/model' to 'CM02'
+> [ 0.000000] (0:maestro@) Configuration change: Set 'network/crosstraffic' to 'no'
+> [ 0.000000] (0:maestro@) Hosts currently registered with this engine: 3
+> [ 0.000000] (0:maestro@) The following hosts have more than one core: MyHost1
+> [ 0.000000] (0:maestro@) The following hosts are SingleCore: MyHost2
+> [ 0.000000] (0:maestro@) The following hosts are SingleCore: MyHost3
+> [ 0.000000] (0:maestro@) A simple example: Let's retrieve all hosts that changed their frequency
+> [ 0.000000] (0:maestro@) The following hosts changed their frequency: MyHost2 (from 100000000.0f to 20000000.0f)
+> [ 0.000000] (0:maestro@) The following hosts have a frequency > 50Mf: MyHost1
+> [ 0.000000] (0:maestro@) The following hosts have a frequency > 50Mf: MyHost3