mlpack  2.2.5

Parses the command line for parameters and holds user-specified parameters. More...

Public Member Functions

 ~CLI ()
 Destructor. More...

 

Static Public Member Functions

static void Add (const std::string &path, const std::string &description, const std::string &alias="", const bool required=false, const bool input=true)
 Adds a parameter to the hierarchy; use the PARAM_*() macros instead of this (i.e. More...

 
template
<
class
T
>
static void Add (const std::string &identifier, const std::string &description, const std::string &alias="", const bool required=false, const bool input=true)
 Adds a parameter to the hierarchy; use the PARAM_*() macros instead of this (i.e. More...

 
static void AddFlag (const std::string &identifier, const std::string &description, const std::string &alias="")
 Adds a flag parameter to the hierarchy; use PARAM_FLAG() instead of this. More...

 
static void DefaultMessages ()
 Parses the parameters for 'help' and 'info'. More...

 
static void Destroy ()
 Destroy the CLI object. More...

 
static std::string GetDescription (const std::string &identifier)
 Get the description of the specified node. More...

 
template
<
typename
T
>
static T & GetParam (const std::string &identifier)
 Grab the value of type T found while parsing. More...

 
static CLIGetSingleton ()
 Retrieve the singleton. More...

 
static bool HasParam (const std::string &identifier)
 See if the specified flag was found while parsing. More...

 
static std::string HyphenateString (const std::string &str, int padding)
 Hyphenate a string or split it onto multiple 80-character lines, with some amount of padding on each line. More...

 
static void ParseCommandLine (int argc, char **argv)
 Parses the commandline for arguments. More...

 
static void Print ()
 Print out the current hierarchy. More...

 
static void PrintHelp (const std::string &param="")
 Print out the help info of the hierarchy. More...

 
static void PrintOutput ()
 Print the value of any output options on stdout. More...

 
static void RegisterProgramDoc (util::ProgramDoc *doc)
 Registers a ProgramDoc object, which contains documentation about the program. More...

 
static void RemoveDuplicateFlags (po::basic_parsed_options< char > &bpo)
 Removes duplicate flags. More...

 

Public Attributes

util::ProgramDocdoc
 Pointer to the ProgramDoc object. More...

 

Detailed Description

Parses the command line for parameters and holds user-specified parameters.

The CLI class is a subsystem by which parameters for machine learning methods can be specified and accessed. In conjunction with the macros PARAM_DOUBLE, PARAM_INT, PARAM_STRING, PARAM_FLAG, and others, this class aims to make user configurability of mlpack methods very easy. There are only three methods in CLI that a user should need: CLI::ParseCommandLine(), CLI::GetParam(), and CLI::HasParam() (in addition to the PARAM_*() macros).

Adding parameters to a program

$ ./executable --bar=5
Note
The = is optional; a space can also be used.

A parameter is specified by using one of the following macros (this is not a complete list; see core/io/cli.hpp):

Parameters
IDName of the parameter.
DESCShort description of the parameter (one/two sentences).
ALIASAn alias for the parameter.
DEFDefault value of the parameter.

The flag (boolean) type automatically defaults to false; it is specified merely as a flag on the command line (no '=true' is required).

Here is an example of a few parameters being defined; this is for the KNN executable (methods/neighbor_search/knn_main.cpp):

PARAM_STRING_REQ("reference_file", "File containing the reference dataset.",
"r");
PARAM_STRING_REQ("distances_file", "File to output distances into.", "d");
PARAM_STRING_REQ("neighbors_file", "File to output neighbors into.", "n");
PARAM_INT_REQ("k", "Number of furthest neighbors to find.", "k");
PARAM_STRING("query_file", "File containing query points (optional).", "q",
"");
PARAM_INT("leaf_size", "Leaf size for tree building.", "l", 20);
PARAM_FLAG("naive", "If true, O(n^2) naive mode is used for computation.",
"N");
PARAM_FLAG("single_mode", "If true, single-tree search is used (as opposed "
"to dual-tree search.", "s");

More documentation is available on the PARAM_*() macros in the documentation for core/io/cli.hpp.

Documenting the program itself

In addition to allowing documentation for each individual parameter and module, the PROGRAM_INFO() macro provides support for documenting the program itself. There should only be one instance of the PROGRAM_INFO() macro. Below is an example:

PROGRAM_INFO("Maximum Variance Unfolding", "This program performs maximum "
"variance unfolding on the given dataset, writing a lower-dimensional "
"unfolded dataset to the given output file.");

This description should be verbose, and explain to a non-expert user what the program does and how to use it. If relevant, paper citations should be included.

Parsing the command line with CLI

To have CLI parse the command line at the beginning of code execution, only a call to ParseCommandLine() is necessary:

int main(int argc, char** argv)
{
CLI::ParseCommandLine(argc, argv);
...
}

CLI provides –help and –info options which give nicely formatted documentation of each option; the documentation is generated from the DESC arguments in the PARAM_*() macros.

Getting parameters with CLI

When the parameters have been defined, the next important thing is how to access them. For this, the HasParam() and GetParam() methods are used. For instance, to see if the user passed the flag (boolean) "naive":

if (CLI::HasParam("naive"))
{
Log::Info << "Naive has been passed!" << std::endl;
}

To get the value of a parameter, such as a string, use GetParam:

const std::string filename = CLI::GetParam<std::string>("filename");
Note
Options should only be defined in files which define main() (that is, main executables). If options are defined elsewhere, they may be spuriously included into other executables and confuse users. Similarly, if your executable has options which you did not define, it is probably because the option is defined somewhere else and included in your executable.
Bug:
The COUNTER variable is used in most cases to guarantee a unique global identifier for options declared using the PARAM_*() macros. However, not all compilers have this support–most notably, gcc < 4.3. In that case, the LINE macro is used as an attempt to get a unique global identifier, but collisions are still possible, and they produce bizarre error messages. See https://github.com/mlpack/mlpack/issues/100 for more information.

Definition at line 194 of file cli.hpp.

Constructor & Destructor Documentation

◆ ~CLI()

~CLI ( )

Destructor.

Member Function Documentation

◆ Add() [1/2]

static void Add ( const std::string &  path,
const std::string &  description,
const std::string &  alias = "",
const bool  required = false,
const bool  input = true 
)
static

Adds a parameter to the hierarchy; use the PARAM_*() macros instead of this (i.e.

PARAM_INT()). Uses char* and not std::string since the vast majority of use cases will be literal strings.

Parameters
identifierThe name of the parameter.
descriptionShort string description of the parameter.
aliasAn alias for the parameter, defaults to "" which is no alias. ("").
requiredIndicates if parameter must be set on command line.
inputIf true, the parameter is an input (not output) parameter.

◆ Add() [2/2]

static void Add ( const std::string &  identifier,
const std::string &  description,
const std::string &  alias = "",
const bool  required = false,
const bool  input = true 
)
static

Adds a parameter to the hierarchy; use the PARAM_*() macros instead of this (i.e.

PARAM_INT()). Uses char* and not std::string since the vast majority of use cases will be literal strings. If the argument requires a parameter, you must specify a type.

Parameters
identifierThe name of the parameter.
descriptionShort string description of the parameter.
aliasAn alias for the parameter, defaults to "" which is no alias.
requiredIndicates if parameter must be set on command line.
inputIf true, the parameter is an input (not output) parameter.

◆ AddFlag()

static void AddFlag ( const std::string &  identifier,
const std::string &  description,
const std::string &  alias = "" 
)
static

Adds a flag parameter to the hierarchy; use PARAM_FLAG() instead of this.

Parameters
identifierThe name of the paramater.
descriptionShort string description of the parameter.
aliasAn alias for the parameter, defaults to "" which is no alias.

◆ DefaultMessages()

static void DefaultMessages ( )
static

Parses the parameters for 'help' and 'info'.

If found, will print out the appropriate information and kill the program.

◆ Destroy()

static void Destroy ( )
static

Destroy the CLI object.

This resets the pointer to the singleton, so in case someone tries to access it after destruction, a new one will be made (the program will not fail).

◆ GetDescription()

static std::string GetDescription ( const std::string &  identifier)
static

Get the description of the specified node.

Parameters
identifierName of the node in question.
Returns
Description of the node in question.

◆ GetParam()

static T& GetParam ( const std::string &  identifier)
static

Grab the value of type T found while parsing.

You can set the value using this reference safely.

Parameters
identifierThe name of the parameter in question.

◆ GetSingleton()

static CLI& GetSingleton ( )
static

Retrieve the singleton.

Not exposed to the outside, so as to spare users some ungainly x.GetSingleton().foo() syntax.

In this case, the singleton is used to store data for the static methods, as there is no point in defining static methods only to have users call private instance methods.

Returns
The singleton instance for use in the static methods.

◆ HasParam()

static bool HasParam ( const std::string &  identifier)
static

See if the specified flag was found while parsing.

Parameters
identifierThe name of the parameter in question.

◆ HyphenateString()

static std::string HyphenateString ( const std::string &  str,
int  padding 
)
static

Hyphenate a string or split it onto multiple 80-character lines, with some amount of padding on each line.

This is ued for option output.

Parameters
strString to hyphenate (splits are on ' ').
paddingAmount of padding on the left for each new line.

◆ ParseCommandLine()

static void ParseCommandLine ( int  argc,
char **  argv 
)
static

Parses the commandline for arguments.

Parameters
argcThe number of arguments on the commandline.
argvThe array of arguments as strings.

◆ Print()

static void Print ( )
static

Print out the current hierarchy.

◆ PrintHelp()

static void PrintHelp ( const std::string &  param = "")
static

Print out the help info of the hierarchy.

◆ PrintOutput()

static void PrintOutput ( )
static

Print the value of any output options on stdout.

◆ RegisterProgramDoc()

static void RegisterProgramDoc ( util::ProgramDoc doc)
static

Registers a ProgramDoc object, which contains documentation about the program.

If this method has been called before (that is, if two ProgramDocs are instantiated in the program), a fatal error will occur.

Parameters
docPointer to the ProgramDoc object.

◆ RemoveDuplicateFlags()

static void RemoveDuplicateFlags ( po::basic_parsed_options< char > &  bpo)
static

Removes duplicate flags.

Parameters
bpoThe basic_program_options to remove duplicate flags from.

Member Data Documentation

◆ doc

Pointer to the ProgramDoc object.

Definition at line 389 of file cli.hpp.


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