OpenTTD Source  20241121-master-g67a0fccfad
FlowStat Class Reference

Flow statistics telling how much flow should be sent along a link. More...

#include <station_base.h>

Public Types

typedef std::map< uint32_t, StationIDSharesMap
 

Public Member Functions

 FlowStat ()
 Invalid constructor. More...
 
 FlowStat (StationID st, uint flow, bool restricted=false)
 Create a FlowStat with an initial entry. More...
 
void AppendShare (StationID st, uint flow, bool restricted=false)
 Add some flow to the end of the shares map. More...
 
uint GetShare (StationID st) const
 Get flow for a station. More...
 
void ChangeShare (StationID st, int flow)
 Change share for specified station. More...
 
void RestrictShare (StationID st)
 Restrict a flow by moving it to the end of the map and decreasing the amount of unrestricted flow. More...
 
void ReleaseShare (StationID st)
 Release ("unrestrict") a flow by moving it to the begin of the map and increasing the amount of unrestricted flow. More...
 
void ScaleToMonthly (uint runtime)
 Scale all shares from link graph's runtime to monthly values. More...
 
const SharesMap * GetShares () const
 Get the actual shares as a const pointer so that they can be iterated over. More...
 
uint GetUnrestricted () const
 Return total amount of unrestricted shares. More...
 
void SwapShares (FlowStat &other)
 Swap the shares maps, and thus the content of this FlowStat with the other one. More...
 
StationID GetViaWithRestricted (bool &is_restricted) const
 Get a station a package can be routed to. More...
 
StationID GetVia () const
 Get a station a package can be routed to. More...
 
StationID GetVia (StationID excluded, StationID excluded2=INVALID_STATION) const
 Get a station a package can be routed to, but exclude the given ones. More...
 
void Invalidate ()
 Reduce all flows to minimum capacity so that they don't get in the way of link usage statistics too much. More...
 

Static Public Attributes

static const SharesMap empty_sharesmap
 Static instance of FlowStat::SharesMap. More...
 

Private Attributes

SharesMap shares
 Shares of flow to be sent via specified station (or consumed locally).
 
uint unrestricted
 Limit for unrestricted shares.
 

Detailed Description

Flow statistics telling how much flow should be sent along a link.

This is done by creating "flow shares" and using std::map's upper_bound() method to look them up with a random number. A flow share is the difference between a key in a map and the previous key. So one key in the map doesn't actually mean anything by itself.

Definition at line 32 of file station_base.h.

Constructor & Destructor Documentation

◆ FlowStat() [1/2]

FlowStat::FlowStat ( )
inline

Invalid constructor.

This can't be called as a FlowStat must not be empty. However, the constructor must be defined and reachable for FlowStat to be used in a std::map.

Definition at line 43 of file station_base.h.

◆ FlowStat() [2/2]

FlowStat::FlowStat ( StationID  st,
uint  flow,
bool  restricted = false 
)
inline

Create a FlowStat with an initial entry.

Parameters
stStation the initial entry refers to.
flowAmount of flow for the initial entry.
restrictedIf the flow to be added is restricted.

Definition at line 51 of file station_base.h.

References shares, and unrestricted.

Member Function Documentation

◆ AppendShare()

void FlowStat::AppendShare ( StationID  st,
uint  flow,
bool  restricted = false 
)
inline

Add some flow to the end of the shares map.

Only do that if you know that the station isn't in the map yet. Anything else may lead to inconsistencies.

Parameters
stRemote station.
flowAmount of flow to be added.
restrictedIf the flow to be added is restricted.

Definition at line 66 of file station_base.h.

References shares, and unrestricted.

Referenced by FlowStatMap::PassOnFlow().

◆ ChangeShare()

void FlowStat::ChangeShare ( StationID  st,
int  flow 
)

Change share for specified station.

By specifying INT_MIN as parameter you can erase a share. Newly added flows will be unrestricted.

Parameters
stNext Hop to be removed.
flowShare to be added or removed.

Definition at line 4874 of file station_cmd.cpp.

References shares, and unrestricted.

Referenced by FlowStatMap::DeleteFlows().

◆ GetShare()

uint FlowStat::GetShare ( StationID  st) const

Get flow for a station.

Parameters
stStation to get flow for.
Returns
Flow for st.

Definition at line 4783 of file station_cmd.cpp.

References shares.

Referenced by FlowStatMap::FinalizeLocalConsumption().

◆ GetShares()

const SharesMap* FlowStat::GetShares ( ) const
inline

Get the actual shares as a const pointer so that they can be iterated over.

Returns
Actual shares.

Definition at line 88 of file station_base.h.

References shares.

Referenced by FlowStatMap::DeleteFlows().

◆ GetUnrestricted()

uint FlowStat::GetUnrestricted ( ) const
inline

Return total amount of unrestricted shares.

Returns
Amount of unrestricted shares.

Definition at line 94 of file station_base.h.

References unrestricted.

◆ GetVia() [1/2]

StationID FlowStat::GetVia ( ) const
inline

Get a station a package can be routed to.

This done by drawing a random number between 0 and sum_shares and then looking that up in the map with lower_bound. So each share gets selected with a probability dependent on its flow. Don't include restricted flows.

Returns
A station ID from the shares map.

Definition at line 130 of file station_base.h.

References RandomRange(), shares, and unrestricted.

◆ GetVia() [2/2]

StationID FlowStat::GetVia ( StationID  excluded,
StationID  excluded2 = INVALID_STATION 
) const

Get a station a package can be routed to, but exclude the given ones.

Parameters
excludedStationID not to be selected.
excluded2Another StationID not to be selected.
Returns
A station ID from the shares map.

Definition at line 4802 of file station_cmd.cpp.

References unrestricted.

◆ GetViaWithRestricted()

StationID FlowStat::GetViaWithRestricted ( bool &  is_restricted) const
inline

Get a station a package can be routed to.

This done by drawing a random number between 0 and sum_shares and then looking that up in the map with lower_bound. So each share gets selected with a probability dependent on its flow. Do include restricted flows here.

Parameters
is_restrictedOutput if a restricted flow was chosen.
Returns
A station ID from the shares map.

Definition at line 115 of file station_base.h.

References RandomRange(), shares, and unrestricted.

◆ Invalidate()

void FlowStat::Invalidate ( )

Reduce all flows to minimum capacity so that they don't get in the way of link usage statistics too much.

Keep them around, though, to continue routing any remaining cargo.

Definition at line 4855 of file station_cmd.cpp.

References shares, and unrestricted.

◆ ReleaseShare()

void FlowStat::ReleaseShare ( StationID  st)

Release ("unrestrict") a flow by moving it to the begin of the map and increasing the amount of unrestricted flow.

Parameters
stStation of flow to be released.

Definition at line 4955 of file station_cmd.cpp.

References shares, and unrestricted.

◆ RestrictShare()

void FlowStat::RestrictShare ( StationID  st)

Restrict a flow by moving it to the end of the map and decreasing the amount of unrestricted flow.

Parameters
stStation of flow to be restricted.

Definition at line 4924 of file station_cmd.cpp.

References shares, and unrestricted.

◆ ScaleToMonthly()

void FlowStat::ScaleToMonthly ( uint  runtime)

Scale all shares from link graph's runtime to monthly values.

Parameters
runtimeTime the link graph has been running without compression.
Precondition
runtime must be greater than 0 as we don't want infinite flow values.

Definition at line 4992 of file station_cmd.cpp.

References shares, and unrestricted.

◆ SwapShares()

void FlowStat::SwapShares ( FlowStat other)
inline

Swap the shares maps, and thus the content of this FlowStat with the other one.

Parameters
otherFlowStat to swap with.

Definition at line 101 of file station_base.h.

References shares, Swap(), and unrestricted.

Field Documentation

◆ empty_sharesmap

const FlowStat::SharesMap FlowStat::empty_sharesmap
static

Static instance of FlowStat::SharesMap.

Note: This instance is created on task start. Lazy creation on first usage results in a data race between the CDist threads.

Definition at line 36 of file station_base.h.

Referenced by FlowEdgeIterator::SetNode().


The documentation for this class was generated from the following files: