22 Appendix D: NED Functions¶

The functions that can be used in NED expressions and ini files are the following. The question mark (as in “rng?”) marks optional arguments.

22.1 Category "conversion":¶

• double : quantity double(any x)
  Converts x to double, and returns the result. A boolean argument becomes 0 or 1; a string is interpreted as number; an XML argument causes an error. Units are preserved.
• int : intquantity int(any x)
  Converts x to int, and returns the result. A boolean argument becomes 0 or 1; a double is converted using floor(); a string is interpreted as number; an XML argument causes an error. Units are preserved.
• string : string string(any x)
  Converts x to string, and returns the result.

22.2 Category "math":¶

• acos : double acos(double)
  Trigonometric function; see standard C function of the same name
• asin : double asin(double)
  Trigonometric function; see standard C function of the same name
• atan : double atan(double)
  Trigonometric function; see standard C function of the same name
• atan2 : double atan2(double, double)
  Trigonometric function; see standard C function of the same name
• ceil : double ceil(double)
  Rounds down; see standard C function of the same name
• cos : double cos(double)
  Trigonometric function; see standard C function of the same name
• exp : double exp(double)
  Exponential; see standard C function of the same name
• fabs : quantity fabs(quantity x)
  Returns the absolute value of the quantity.
• floor : double floor(double)
  Rounds up; see standard C function of the same name
• fmod : quantity fmod(quantity x, quantity y)
  Returns the floating-point remainder of x/y; unit conversion takes place if needed.
• hypot : double hypot(double, double)
  Length of the hypotenuse; see standard C function of the same name
• log : double log(double)
  Natural logarithm; see standard C function of the same name
• log10 : double log10(double)
  Base-10 logarithm; see standard C function of the same name
• max : quantity max(quantity a, quantity b)
  Returns the greater one of the two quantities; unit conversion takes place if needed.
• min : quantity min(quantity a, quantity b)
  Returns the smaller one of the two quantities; unit conversion takes place if needed.
• pow : double pow(double, double)
  Power; see standard C function of the same name
• sin : double sin(double)
  Trigonometric function; see standard C function of the same name
• sqrt : double sqrt(double)
  Square root; see standard C function of the same name
• tan : double tan(double)
  Trigonometric function; see standard C function of the same name

22.3 Category "misc":¶

• firstAvailable : string firstAvailable(...)
  Accepts any number of strings, interprets them as NED type names (qualified or unqualified), and returns the first one that exists and its C++ implementation class is also available. Throws an error if none of the types are available.
• select : any select(int index, ...)
  Returns the <index>th item from the rest of the argument list; numbering starts from 0.
• simTime : quantity simTime()
  Returns the current simulation time.

22.4 Category "ned":¶

• ancestorIndex : int ancestorIndex(int numLevels)
  Returns the index of the ancestor module numLevels levels above the module or channel in context.
• fullName : string fullName()
  Returns the full name of the module or channel in context.
• fullPath : string fullPath()
  Returns the full path of the module or channel in context.
• parentIndex : int parentIndex()
  Returns the index of the parent module, which has to be part of module vector.

22.5 Category "random/continuous":¶

• beta : double beta(double alpha1, double alpha2, int rng?)
  Returns a random number from the Beta distribution
• cauchy : quantity cauchy(quantity a, quantity b, int rng?)
  Returns a random number from the Cauchy distribution
• chi_square : double chi_square(int k, int rng?)
  Returns a random number from the Chi-square distribution
• erlang_k : quantity erlang_k(int k, quantity mean, int rng?)
  Returns a random number from the Erlang distribution
• exponential : quantity exponential(quantity mean, int rng?)
  Returns a random number from the Exponential distribution
• gamma_d : quantity gamma_d(double alpha, quantity theta, int rng?)
  Returns a random number from the Gamma distribution
• lognormal : double lognormal(double m, double w, int rng?)
  Returns a random number from the Lognormal distribution
• normal : quantity normal(quantity mean, quantity stddev, int rng?)
  Returns a random number from the Normal distribution
• pareto_shifted : quantity pareto_shifted(double a, quantity b, quantity c, int rng?)
  Returns a random number from the Pareto-shifted distribution
• student_t : double student_t(int i, int rng?)
  Returns a random number from the Student-t distribution
• triang : quantity triang(quantity a, quantity b, quantity c, int rng?)
  Returns a random number from the Triangular distribution
• truncnormal : quantity truncnormal(quantity mean, quantity stddev, int rng?)
  Returns a random number from the truncated Normal distribution
• uniform : quantity uniform(quantity a, quantity b, int rng?)
  Returns a random number from the Uniform distribution
• weibull : quantity weibull(quantity a, quantity b, int rng?)
  Returns a random number from the Weibull distribution

22.6 Category "random/discrete":¶

• bernoulli : int bernoulli(double p, int rng?)
  Returns a random number from the Bernoulli distribution
• binomial : int binomial(int n, double p, int rng?)
  Returns a random number from the Binomial distribution
• geometric : int geometric(double p, int rng?)
  Returns a random number from the Geometric distribution
• intuniform : int intuniform(intquantity a, intquantity b, int rng?)
  Returns a random integer uniformly distributed over [a, b]
• negbinomial : int negbinomial(int n, double p, int rng?)
  Returns a random number from the Negbinomial distribution
• poisson : int poisson(double lambda, int rng?)
  Returns a random number from the Poisson distribution

22.7 Category "strings":¶

• choose : string choose(int index, string list)
  Interprets list as a space-separated list, and returns the item at the given index. Negative and out-of-bounds indices cause an error.
• contains : bool contains(string s, string substr)
  Returns true if string s contains substr as substring
• endsWith : bool endsWith(string s, string substr)
  Returns true if s ends with the substring substr.
• expand : string expand(string s)
  Expands $ variables ($configname, $runnumber, etc.) in the given string, and returns the result.
• indexOf : int indexOf(string s, string substr)
  Returns the position of the first occurrence of substring substr in s, or -1 if s does not contain substr.
• length : int length(string s)
  Returns the length of the string
• replace : string replace(string s, string substr, string repl, int startPos?)
  Replaces all occurrences of substr in s with the string repl. If startPos is given, search begins from position startPos in s.
• replaceFirst : string replaceFirst(string s, string substr, string repl, int startPos?)
  Replaces the first occurrence of substr in s with the string repl. If startPos is given, search begins from position startPos in s.
• startsWith : bool startsWith(string s, string substr)
  Returns true if s begins with the substring substr.
• substring : string substring(string s, int pos, int len?)
  Return the substring of s starting at the given position, either to the end of the string or maximum len characters
• substringAfter : string substringAfter(string s, string substr)
  Returns the substring of s after the first occurrence of substr, or the empty string if s does not contain substr.
• substringAfterLast : string substringAfterLast(string s, string substr)
  Returns the substring of s after the last occurrence of substr, or the empty string if s does not contain substr.
• substringBefore : string substringBefore(string s, string substr)
  Returns the substring of s before the first occurrence of substr, or the empty string if s does not contain substr.
• substringBeforeLast : string substringBeforeLast(string s, string substr)
  Returns the substring of s before the last occurrence of substr, or the empty string if s does not contain substr.
• tail : string tail(string s, int len)
  Returns the last len character of s, or the full s if it is shorter than len characters.
• toLower : string toLower(string s)
  Converts s to all lowercase, and returns the result.
• toUpper : string toUpper(string s)
  Converts s to all uppercase, and returns the result.
• trim : string trim(string s)
  Discards whitespace from the start and end of s, and returns the result.

22.8 Category "units":¶

• convertUnit : quantity convertUnit(quantity x, string unit)
  Converts x to the given unit.
• dropUnit : double dropUnit(quantity x)
  Removes the unit of measurement from quantity x.
• replaceUnit : quantity replaceUnit(quantity x, string unit)
  Replaces the unit of x with the given unit.
• unitOf : string unitOf(quantity x)
  Returns the unit of the given quantity.

22.9 Category "units/conversion":¶

• A : quantity A(quantity x)
  Converts to A (ampere) from a compatible unit or a dimensionless number.
• Ah : quantity Ah(quantity x)
  Converts to Ah (ampere-hour) from a compatible unit or a dimensionless number.
• As : quantity As(quantity x)
  Converts to As (ampere-second) from a compatible unit or a dimensionless number.
• B : quantity B(quantity x)
  Converts to B (byte) from a compatible unit or a dimensionless number.
• C : quantity C(quantity x)
  Converts to C (coulomb) from a compatible unit or a dimensionless number.
• GB : quantity GB(quantity x)
  Converts to GB (gigabyte) from a compatible unit or a dimensionless number.
• GHz : quantity GHz(quantity x)
  Converts to GHz (gigahertz) from a compatible unit or a dimensionless number.
• etc.

A similar NED function exists for all registered measurement units. Units are listed in section [19.5.9].

22.10 Category "xml":¶

• xml : xml xml(string xmlstring, string xpath?)
  Parses the given XML string into a cXMLElement tree, and returns the root element. When called with two arguments, it returns the first element from the tree that matches the expression given in simplified XPath syntax.
• xmldoc : xml xmldoc(string filename, string xpath?)
  Parses the given XML file into a cXMLElement tree, and returns the root element. When called with two arguments, it returns the first element from the tree that matches the expression given in simplified XPath syntax.