Various functions and classes

Sort

Syntax :

  void Sort(int& a, int& b);
  void Sort(TinyVector& a, TinyVector& b);
  void Sort(int& a, int& b, int& c);
  void Sort(int& a, int& b, int& c, int& d);

This function sorts the arguments (a, b, c and d for the last syntax) in ascending order.

Example :

int a = 3, b = 5, c = -4;

// we should obtain a = -4, b = 3, c = 5
Sort(a, b, c);

Location :

Check_And_ReallocateIfNecessary

Syntax :

  void Check_And_ReallocateIfNecessary(Vector& X, int n);

This function checks if the size of x is greater or equal to n. If the size of x is lower than n, the vector is resized to contain 1.5*n + 2 elements.

Example :

// in order to avoid too many reallocations
// which is the case for PushBack
// you can use this function
Vector<double> num;

int i = 0, n = 0;
while (i != 4)
  {
    n++;
    Check_And_ReallocateIfNecessary(num, n);
    i = rand();
    num(n-1) = i;
  }

// once num is filled, you can resize it to its exact size
num.Resize(n);

Location :

SetIncidentAngle

Syntax :

  void SetIncidentAngle(const T& omega, TinyVector& kwave, const T& teta, const T& phi);

This function fills the wave vector kwave with the amplitude omega and the two incident angles teta and phi. This function is available in 2-D and 3-D. In 2-D the wave vector is equal to (ω cos θ, ω sin θ). In 3-D the wave vector is equal to (ω sin θ cos φ, ω sin θ sin φ, ω cos θ). In 2-D, this function is the reciprocal function of CartesianToPolar. In 3-D, this is the reciprocal function of CartesianToSpherical.

Example :

Real_wp omega = pi_wp;
Real_wp teta = 0.5*pi_wp, phi = pi_wp;
TinyVector<Real_wp, 3> kwave;

// we compute the wave vector kwave from the wave number omega
// and the two incident angles teta and phi
SetIncidentAngle(omega, kwave, teta, phi);

// if you want to find original omega(=r in spherical coordinates), teta and phi from kwave you can call  CartesianToSpherical
Real_wp theta0, phi0, cos_teta0, sin_teta0;
CartesianToSpherical(kwave(0), kwave(1), kwave(2), theta0, phi0, cos_teta0, sin_teta0);
// teta0 and phi0 should be equal to teta and phi

Location :

PrintNoBrackets

Syntax :

  void PrintNoBrackets(ostream& out, const Vector& u);
  void PrintNoBrackets(ostream& out, const TinyVector& u);

This function prints vectors or tiny vectors without brackets and commas.

Example :

TinyVector<double, 5> x;

// cout << x will display x with parenthesis and commas
// PrintNoBrackets prints the values of x separated by spaces
PrintNoBrackets(cout, x);

// you can also display a vector of tiny vectors
Vector<TinyVector<double, 5> > y;
PrintNoBrackets(cout, y);

Location :

GetMemorySize

Syntax :

  size_t GetMemorySize(const Vector<Vector>&);
  size_t GetMemorySize(const Vector<Matrix>&);
  size_t GetMemorySize(const Matrix<Matrix>&);
  size_t GetMemorySize(const Vector<Vector<Vector> >&);
  size_t GetMemorySize(const Vector<Vector<Matrix> >&);
  size_t GetMemorySize(const Vector<TinyVector<Vector> >&);
  size_t GetMemorySize(const TinyVector<Vector>&);

This function returns the memory (in bytes) used by composed structures such as vector of vectors, vector of matrices, etc.

Example :

Vector<Vector<double> > x;

// if you want to know the size used to store x (all the values)
size_t taille = GetMemorySize(x);

Location :

FillZero

Syntax :

  template<class T>
  void FillZero(T&);

This function sets to 0 all the elements of the structure by calling function FillZero on each element of the structure.

Example :

// it works for any type
Matrix<TinyVector<double, 3> > B(3, 3);
FillZero(B);

Location :

TinyMatrix.cxx

MakeLink

Syntax :

  void MakeLink(string source, string destination);

This function creates a symbolic link. source is the original file. destination is the created symbolic link pointing to the original file.

Example :

// disque_bis.mesh will be a link pointing to disque.mesh
MakeLink("disque.mesh", "disque_bis.mesh");

Location :

CopyFile

Syntax :

  void CopyFile(string source, string destination);

This function copies the source file to a destination file.

Example :

// disque_bis.mesh will be a hard copy of disque.mesh
CopyFile("disque.mesh", "disque_bis.mesh");

Location :

StringTokenize

Syntax :

  void StringTokenize(string phrase, Vector<string>& mots, string delim);

This function splits the string phrase into words contained in the variable mots. The words are assumed to be separated by one of the character contained in delim.

Example :

string phrase = "coucou me   voila.";
Vector<string> mots;

// if the words are separated with space or tab character
StringTokenize(phrase, mots, " \t");

// mots should contain "coucou", "me" and "voila."
DISP(mots);

Location :

StringTrim

Syntax :

  void StringTrim(string& s);

This function removes spaces contained in the string s.

Example :

string s = "  Coucou Me   Voila. ";

StringTrim(s);
// s should be equal to "CoucouMeVoila."

Location :

DeleteSpaceAtExtremityOfString

Syntax :

  void DeleteSpaceAtExtremityOfString(string& s);

This function removes spaces located at the extremities of the string s.

Example :

string s = "  Coucou Me   Voila. ";

DeleteSpaceAtExtremityOfString(s);
// s should be equal to "Coucou Me   Voila."

Location :

NumberToString

Syntax :

  string NumberToString(int n);
  string NumberToString(int n, int nb_char);

This function returns the string corresponding to n with additional zeros on the left. By default, the returned string should contain 4 characters. The second argument is optional and specifies the number of characters of the returned string.

Example :

// s should be equal to "0023"
string s = NumberToString(23);

// s should be equal to "000023"
s = NumberToString(23, 6);

Location :

Linspace

Syntax :

  void Linspace(T a, T b, int N, Vector<T>& x);

This function computes a regular subdivision of the interval [a, b] with N points. The result is placed in vector x.

Example :

Vector<double> x;
double a = -2.0, b = 3.0;

// to produce a vector of 100 points uniformly distributed
// in the interval [a, b] :
Linspace(a, b, 100, x);

Location :

GetHumanReadableMemory

Syntax :

  string GetHumanReadableMemory(size_t taille);

This function returns a string describing taille in human-readable string. The string contains the quantity with the unit (bytes, KiB, MiB, etc).

Example :

Vector<double> x;

// if you want to display the memory used to store x
// with readable units :
cout << "Memory used to store x = " << GetHumanReadableMemory(x.GetMemorySize()) << endl;

Location :

InitMontjoie

Syntax :

  void InitMontjoie(int argc, char** argv);
  void InitMontjoie(int argc, char** argv, int print_level);

This function should be called prior to any Montjoie function. Usually it is called in the main function of all targets. It calls MPI_Init (if MPI is used in the Makefile), and completes other initializations. The third argument is optional and sets the verbosity level of this function. By default, it will display the MPI_Init_thread level (MPI_THREAD_SINGLE, MPI_THREAD_FUNNELED, MPI_THREAD_SERIALIZED or MPI_THREAD_MULTIPLE).

Example :

// for any new main function
#include "Montjoie.hxx"

using namespace Montjoie;

int main(int argc, char** argv)
{
  // prior to any call to Montjoie functions : InitMontjoie should be called
  // this function calls MPI_Init
  InitMontjoie(argc, argv);

  // here you can call any function


  // finally, MPI_Finalize is called through FinalizeMontjoie
  return FinalizeMontjoie();
}

Location :

Share/MontjoieTypes.cxx

FinalizeMontjoie

Syntax :

  int FinalizeMontjoie();

This function should be called before ending the program for a clean termination of all processes. It calls MPI_Finalize.

Example :

// for any new main function
#include "Montjoie.hxx"

using namespace Montjoie;

int main(int argc, char** argv)
{
  // prior to any call to Montjoie functions : InitMontjoie should be called
  // this function calls MPI_Init
  InitMontjoie(argc, argv);

  // here you can call any function


  // finally, MPI_Finalize is called through FinalizeMontjoie
  return FinalizeMontjoie();
}

Location :

Share/MontjoieTypes.cxx

toInteger

Syntax :

  int toInteger(Real_wp x);

This function converts a float into an integer

Example :

Real_wp x = 2.8;

// closest integer with round
int n = toInteger(round(x));

Location :

toDouble

Syntax :

  double toDouble(Real_wp x);

This function converts a float into a double.

Example :

Real_wp x = 2.8;

// conversion in double precision
double t = toDouble(x);

Location :

GetPrecisionMachine

Syntax :

  T GetPrecisionMachine(T x);

This function computes the machine precision (i.e. the difference between 1 and its closest number in the representation of type T) of the type T. This function is used in InitMontjoie to compute epsilon_machine which is the precision for Real_wp.

Example :

// machine precision for long double
long double x;
long double eps = GetPrecisionMachine(x);

Location :

to_complex

Syntax :

  to_complex(T x, T& y);

This function converts x in y. If x is complex and y real, it takes the real part of x.

Example :

Real_wp x = 0.3;
Complex_wp y;

// we copy x into y
to_complex(x, y);

// for the reverse operation x = real(y)
to_complex(y, x);

Location :

SetImaginaryI

Syntax :

  void SetImaginaryI(Real_wp& x); 
  void SetImaginaryI(Complex_wp& x);

If the argument is complex, it is set to the pure imaginary number i. If the argument is real, it is set to one.

Example :

Real_wp x = 0.3;
Complex_wp y;

// y = i
SetImaginaryI(y);

// x = 1
SetImaginaryI(x);

Location :

realpart

Syntax :

  T realpart(T x);
  T realpart(complex<T> x);

If the argument is complex, it returns the real part. If the argument is real, it returns the argument.

Example :

Real_wp x = 0.3;
Complex_wp y(0.5, -0.2);

// returns x since x is real
Real_wp xr = realpart(x);

// returns real(y) = 0.5
xr = realpart(y);

Location :

imagpart

Syntax :

  T imagpart(T x);
  T imagpart(complex<T> x);

If the argument is complex, it returns the imaginary part. If the argument is real, it returns zero.

Example :

Real_wp x = 0.3;
Complex_wp y(0.5, -0.2);

// returns 0 since x is real
Real_wp xi = imagpart(x);

// returns imag(y) = -0.2
xr = imagpart(y);

Location :

sign

Syntax :

  T sign(T x);

It returns -1 if x is nonpositive, 1 otherwise.

Example :

Real_wp x = 0.3;

// returns 1.0
Real_wp s = sign(x);

// returns -1.0
s = sign(-x);

Location :

Sqrt

Syntax :

  T Sqrt(T x);

It returns the square root of x.

Example :

Real_wp x = 0.3;

// equivalent to sqrt
Real_wp s = Sqrt(x);

Location :

abs_real

Syntax :

  T abs_real(T x);

It returns abs(real(x)) if x is complex, otherwise it returns abs(x) if x is real.

Example :

Complex_wp z(-0.3, 0.8);

// the result should be 0.3
Real_wp s = abs_real(z);

Location :

abs_cplx

Syntax :

  T abs_cplx(T x);

It is equivalent to function abs.

Example :

Complex_wp z(-0.3, 0.8);

// the result should be the modulus of z
Real_wp s = abs(z);

Location :

abs_cplx

Syntax :

  bool isnan(complex<T> x);

It returns true if the real part or imaginary part is nan (not a number).

Example :

Complex_wp z(-0.3, nan);

// the result should be true
bool s = isnan(z);

Location :

InitPrecisionConstants

Syntax :

  void InitPrecisionConstants();

It is called by InitMontjoie and sets pi_wp, Iwp and epsilon_machine. Since InitMontjoie is usually called, this function should not be called.

Example :

InitPrecisionConstants();

Location :

Clear

Syntax :

  void Clear();

This method releases the memory used by the object.

Example :

VarRandomGenerator var_random;

// selecting a random generator 
var_random.SetRandomGenerator(var_random.GSL_RANLUX);

// then you use the random generator
Real_wp y = var_random.GetRand();

// you can erase the object
var_random.Clear();

Location :

RoundToSquare

Syntax :

  void RoundToSquare(int& n, Real_wp alpha, int& nx, int& ny);
  void RoundToSquare(int& n, Real_wp alpha, Real_wp beta, int& nx, int& ny, int& nz);

This static method modifies the integer n such that n = nx*ny where ny is close to alpha*nx. The second syntax is designed for 3-D, by searching n = nx*ny*nz where ny is close to alpha*nx and nz close to beta*nx.

Example :

// you have a target (number of points)
int N = 40000;

// ratio between the number of points in y and in x
Real_wp alpha = 2.0;

// then you want to construct a 2-D grid with approximatively this number of points
// the 2-D grid contains nx points along x and ny points along y
// and you want to have ny = alpha*nx (for a square, alpha is equal to 1)
// RoundToSquare will give you N such that N = nx*ny and ny approximatively equal to alpha*nx
int nx, ny;
VarRandomGenerator::RoundToSquare(N, alpha, nx, ny);

cout << "Number of points in x, y : " << nx << " " << ny << endl;

// for 3-D grid, you need to know a ratio beta such that nz \approx beta*nx
Real_wp beta = 1.5;
int nz;
VarRandomGenerator::RoundToSquare(N, alpha, beta, nx, ny, nz);

Location :

GetRand

Syntax :

  Real_wp GetRand();

This method returns a random number between 0 and 1.

Example :

VarRandomGenerator var_random;

// selecting a random generator (otherwise it will use rand() function)
var_random.SetRandomGenerator(var_random.GSL_RANLUX);

// then you use the random generator
Real_wp y = var_random.GetRand();
Real_wp z = var_random.GetRand();

Location :

GenerateRandomNumbers

Syntax :

  void GenerateRandomNumbers(int N, VectReal_wp& R);

This method fills the vector R with N random numbers between 0 and 1.

Example :

VarRandomGenerator var_random;

// selecting a random generator (otherwise it will use rand() function)
var_random.SetRandomGenerator(var_random.GSL_RANLUX);

// if you want to generate N random values
int N = 100;
VectReal_wp val;
var_random.GenerateRandomNumbers(N, val);

Location :

ApplyRandomPermutation

Syntax :

  void ApplyRandomPermutation(VectReal_wp& R);

This method shuffles values contained in R. R is replaced by R(P) where P is a random permutation.

Example :

VarRandomGenerator var_random;

// selecting a random generator (otherwise it will use rand() function)
var_random.SetRandomGenerator(var_random.GSL_RANLUX);

// a vector x is constructed
VectReal_wp x;
Linspace(-1.0, 1.0, 100, x);

// then if you want to permute randomly values contained in x
var_random.ApplyRandomPermutation(x);

Location :

GenerateRandomPermutation

Syntax :

  void GenerateRandomPermutation(int N, IVect& permut);

This method generates a random permutation, and stores this permutation in the output argument permut.

Example :

VarRandomGenerator var_random;

// selecting a random generator (otherwise it will use rand() function)
var_random.SetRandomGenerator(var_random.GSL_RANLUX);

int N = 100;

// then if you want to obtain a random permutation
// i.e. numbers 0, 1, 2, .., N-1 shuffled
IVect permut;
var_random.GenerateRandomPermutation(N, permut);

Location :

SetRandomGenerator

Syntax :

  void SetRandomGenerator(int type);

This method selects the random generator to be used. It also initializes the random generator. For the default random generator, it will call srand(time(NULL)). The different types are RANDOM, BIT_REVERSED, GSL_MT19937, GSL_RANLXD1, GSL_RANLXD2, GSL_RANLUX, GSL_RANLUX389, GSL_CMRG, GSL_MRG, GSL_TAUS, GSL_TAUS2, GSL_GFSR4. RANDOM corresponds to the function rand().

Example :

VarRandomGenerator var_random;

// selecting a random generator (otherwise it will use rand() function)
var_random.SetRandomGenerator(var_random.GSL_RANLUX);

// once the random generator is selected, you can generate 
// as many random numbers as you want
Real_wp x = var_random.GetRand();

Location :

SetInputRandomGenerator

Syntax :

  void SetInputRandomGenerator(string nom);

Example :

VarRandomGenerator var_random;

// selecting a random generator (otherwise it will use rand() function)
var_random.SetInputRandomGenerator("GSL_RANLUX");

// once the random generator is selected, you can generate 
// as many random numbers as you want
Real_wp x = var_random.GetRand();

Location :

GenerateBitReversedNumbers

Syntax :

  void GenerateBitReversedNumbers(int n, VectReal_wp& x);

This method generates random numbers with the bit-reversed method.

Example :

VarRandomGenerator var_random;

// selecting a random generator (otherwise it will use rand() function)
var_random.SetInputRandomGenerator("GSL_RANLUX");

// if GenerateBitReversedNumbers is called, the selected random generator
// is not called, but the random numbers are generated with the bit-reversed method
int N = 100;
VectReal_wp x;
var_random.GenerateBitReversedNumbers(N, x);

Location :

FindPrimeNumbers

Syntax :

  void FindPrimeNumbers(IVect& prime_numbers, int N);

This function computes all the prime numbers less than 2*N. These prime numbers are stored in the array prime_numbers. They are computed with a Eratosthene's sieve.

Example :

IVect prime_numbers;
// for example, if you want to know all prime numbers p <= 2*N
int N = 100;
FindPrimeNumbers(prime_numbers, N);

// the prime numbers are stored in the array prime_numbers;

Location :

FindPrimeDecomposition

Syntax :

  void FindPrimeDecomposition(int n, IVect& prime_decomp, const IVect& prime_num);
  void FindPrimeDecomposition(int n, IVect& prime_decomp);

This function finds the decomposition of an integer n into prime numbers whose list is provided in the array prime_num. The result is stored in prime_decomp. If n is not factorizable with the prime numbers contained in prime_num, prime_decomp will store in the last element the irreducible factor. The second syntax computes the decomposition without providing prime numbers. In that case, prime numbers are automatically computed such that there is no irreducible factor.

Example :

IVect prime_numbers;
// for example, if you want to know all prime numbers p <= 2*N
int N = 100;
FindPrimeNumbers(prime_numbers, N);

// the prime numbers are stored in the array prime_numbers
int p = 2*2*2*3*3*11*17*17;
// p is factorized with prime_numbers that have been computed
IVect prime_decomp;
FindPrimeDecomposition(p, prime_decomp, prime_numbers);

// here prime_decomp should give (2, 2, 2, 3, 3, 11, 17, 17)
// the prime number is repeated with its power

// here prime_numbers will be equal to (2, 3, 5, 7)
FindPrimeNumbers(prime_numbers, 5);

// p is not decomposable with only these prime numbers
// p = 2*2*2*3*3* (11*17*17)
// the irreducible factor is 11*17*17 = 3179
FindPrimeDecomposition(p, prime_decomp, prime_numbers);

// prime_decomp should be equal to (2, 2, 2, 3, 3, 3179)

// if you do not want to provide prime numbers
// and compute the decomposition will all prime numbers 
// that can appear in the decomposition of p
FindPrimeDecomposition(p, prime_decomp);

// here prime_decomp should give (2, 2, 2, 3, 3, 11, 17, 17)

Location :

FindPrimeFactorizaion

Syntax :

  void FindPrimeFactorization(int& n, IVect& prime_decomp, const IVect& prime_num);
  void FindPrimeFactorization(int& n, IVect& prime_decomp, int pmax);

This function increases n until that n is an exact product of prime numbers stored in prime_num. In the second syntax, pmax is the maximal prime number allowed.

Example :

IVect prime_numbers;
// prime_numbers = (2, 3, 5, 7)
FindPrimeNumbers(prime_numbers, 5);

// 37 is a prime number that cannot be decomposed with 2, 3, 5 and 7
int p = 37;
// you can ask for the nearest integer greater than p, such that
// p_new = pow(2, n1)*pow(3, n2)*pow(5, n3)*pow(6, n4)
int p_new = p;
IVect prime_decomp;
FindPrimeFactorization(p_new, prime_decomp, prime_numbers);

// here it should find p_new = 40 and prime_decomp = (2, 2, 2, 5)

// the result should be the same, the third argument if the maximum prime number, you allow in the decomposition of p_new
p_new = 37;
FindPrimeFactorization(p_new, prime_decomp, 7);

Location :

FindTwoFactors

Syntax :

  void FindTwoFactors(int n, int& nx, int& ny);

This function computes nx and ny such that n = nx*ny (exactly) with nx and ny as close as possible.

Example :

int N = 20, nx ny;
// here it should find nx = 4 and ny = 5
FindTwoFactors(N, nx, ny);

Location :

FindClosestPow2

Syntax :

  int FindClosestPow2(int n);

This function returns the power of 2 that is the closest integer greater than n.

Example :

// approximate number of points
int N = 1000;
int nb_points = FindClosestPow2(N);

// here you should have nb_points = 1024 = pow(2, 10);

Location :

FindClosestPow23

Syntax :

  int FindClosestPow23(int n);

This function returns an integer 2ⁱ 3^j that is the closest integer greater than n.

Example :

// approximate number of points
int N = 900;
int nb_points = FindClosestPow23(N);

// here you should have nb_points = 972 = 2*2*3*3*3*3*3

Location :

FindClosestPow235

Syntax :

  int FindClosestPow235(int n);

This function returns an integer 2ⁱ 3^j 5^k that is the closest integer greater than n.

Example :

// approximate number of points
int N = 950;
int nb_points = FindClosestPow235(N);

// here you should have nb_points = 960 = 2*2*2*2*2*2*3*5

Location :

FindClosestPow2357

Syntax :

  int FindClosestPow2357(int n);

This function returns an integer 2ⁱ 3^j 5^k 7^m that is the closest integer greater than n.

Example :

// approximate number of points
int N = 975;
int nb_points = FindClosestPow2357(N);

// here you should have nb_points = 980 = 2*2*5*7*7

Location :

ExtendIntegerInterval

Syntax :

  void ExtendIntegerInterval(int& i0, int& i1, int Nt, int n);

This function extends the interval [i0, i1] such that they stay within the interval [0, Nt-1] and i1-i0+1 = N.

Example :

int i0 = 2, i1 = 10;
int Nt = 20; int N = 12;

// i0 is decremented and i1 incremented such that 
// the interval [i0, i1] contains N elements
// i0 and i1 must stay between 0 and Nt-1
ExtendIntegerInterval(i0, i1, Nt, N);

Location :

EvaluateContinuedFraction

Syntax :

  void EvaluateContinuedFraction(const Vector<int>& num, Real_wp& x);

This function evaluates the continued fraction stored in num. The result is placed in x.

Example :

// continued fraction a0 + 1 / (a1 + 1/(a2 + 1/...)) 
// coefficients a0, a1, a2 are stored in num
Vector<int> num(3);
num(0) = 2; num(1) = 4; num(2) = 3;

// evaluation of the continued fraction
Real_wp x;
EvaluateContinuedFraction(num, x);

Location :

DecomposeContinuedFraction

Syntax :

  void DecomposeContinuedFraction(Real_wp x, Real_wp epsilon, IVect& decomp);

This function constructs the continued fraction that is an approximation of x. The continued fraction is stopped as soon as the result is close enough to x (with a threshold epsilon).

Example :

// continued fraction of pi with an accuracy of 1e-6
IVect decomp;
DecomposeContinuedFraction(pi_wp, Real_wp(1e-6), decomp);

Location :

GetNumeratorDenominator

Syntax :

  void GetNumeratorDenominator(const IVect& decomp, int& num, int& denom);

This function computes the numerator and denominator of a continued fraction.

Example :

// continued fraction of pi with an accuracy of 1e-6
IVect decomp;
DecomposeContinuedFraction(pi_wp, Real_wp(1e-6), decomp); 

// then you can compute p and q, such that p/q is the fraction approximating pi
int p, q;
GetNumeratorDenominator(decomp, p, q);

Location :

GetNumber

Syntax :

  int GetNumber();

This method creates a new timer and returns the number associated with this timer.

Example :

// object containing a set of timers
BasicTimer timer;

// if you want to create a new timer
int jeton = timer.GetNumber();

// then you can start the timer with the retrieved number
timer.Start(jeton);

// perform operations
...

// then stop the timer
timer.Stop(jeton);

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds(jeton) << endl;

Location :

ReleaseNumber

Syntax :

  void ReleaseNumber(int n);

This method destroys the timer n.

Example :

// object containing a set of timers
BasicTimer timer;

// if you want to create a new timer
int jeton = timer.GetNumber();

// then you can start the timer with the retrieved number
timer.Start(jeton);

// perform operations
...

// then stop the timer
timer.Stop(jeton);

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds(jeton) << endl;

// once you no longer need this timer, you can release the number
timer.ReleaseNumber(jeton);

Location :

ReserveNumber

Syntax :

  void ReserveNumber(int n);

This method reserves the timer n. It may destroy an already existing number or be in concurrence with predefined timers (ALL, PROD, etc). So this functionality should be used cautiously.

Example :

// object containing a set of timers
BasicTimer timer;

// if you want to reserve some numbers
timer.ReserveNumber(0);
timer.ReserveNumber(1);

// then you can start the timer with the reserved numbers
timer.Start(0);

// perform operations
...

// then stop the timer
timer.Stop(0);

timer.Start(1);

// perform operations
...

// then stop the timer
timer.Stop(1);

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds(0) << endl;
cout << "Time spent = " << timer.GetSeconds(1) << endl;

Location :

Reset

Syntax :

  void Reset(int n);

This method resets the timer n, i.e. the elapsed time is set to 0 for this timer.

Example :

// object containing a set of timers
BasicTimer timer;

// if you want to create a new timer
int jeton = timer.GetNumber();

// then you can start the timer with the retrieved number
timer.Start(jeton);

// perform operations
...

// then stop the timer
timer.Stop(jeton);

// if you restart the timer, the time is incremented
timer.Start(jeton);

// other operations
...

// final stop
timer.Stop(jeton);

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds(jeton) << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset(jeton);

Location :

Start

Syntax :

  void Start(int n);

This method starts the timer n. The elapsed time is incremented.

Example :

// object containing a set of timers
BasicTimer timer;

// if you want to create a new timer
int jeton = timer.GetNumber();

// then you can start the timer with the retrieved number
timer.Start(jeton);

// perform operations
...

// then stop the timer
timer.Stop(jeton);

// if you start again the timer, the time is incremented
timer.Start(jeton);

// other operations
...

// final stop
timer.Stop(jeton);

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds(jeton) << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset(jeton);

Location :

Stop

Syntax :

  void Stop(int n);

This method stops the timer n. The elapsed time is updated only when this method is called.

Example :

// object containing a set of timers
BasicTimer timer;

// if you want to create a new timer
int jeton = timer.GetNumber();

// then you can start the timer with the retrieved number
timer.Start(jeton);

// perform operations
...

// then stop the timer
timer.Stop(jeton);

// if you start again the timer, the time is incremented
timer.Start(jeton);

// other operations
...

// final stop
timer.Stop(jeton);

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds(jeton) << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset(jeton);

Location :

GetSeconds

Syntax :

  double GetSeconds(int n);

This method returns the elapsed time between a call to Start and a call to Stop. The elapsed time is updated only when the method Stop is called.

Example :

// object containing a set of timers
BasicTimer timer;

// if you want to create a new timer
int jeton = timer.GetNumber();

// then you can start the timer with the retrieved number
timer.Start(jeton);

// perform operations
...

// then stop the timer
timer.Stop(jeton);

// if you start again the timer, the time is incremented
timer.Start(jeton);

// other operations
...

// final stop
timer.Stop(jeton);

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds(jeton) << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset(jeton);

Location :

SetTimer

Syntax :

  void SetTimer(int type);

This method changes the timing system to use. The choices are BASIC_TIMER, ACCURATE_TIMER and REAL_TIMER (they use respectively the classes BasicTimer, AccurateTimer and RealTimer). When this method is called, all previous timers are erased.

Example :

// object containing a set of timers
MontjoieTimer timer;

// the choice of the timer can be changed before creating timers
timer.SetTimer(MontjoieTimer::ACCURATE_TIMER);

// once the choice is made, it will use the asked timing system for all functions
// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with the retrieved number
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

Location :

SetCommunicator

Syntax :

  void SetCommunicator(MPI::Comm);

This method sets the MPI communicator to use when GetGlobalSeconds is called.

Example :

// object containing a set of timers
MontjoieTimer timer;

// the choice of the timer can be changed before creating timers
timer.SetTimer(MontjoieTimer::ACCURATE_TIMER);

// the communicator can be set anywhere before a call to GetGlobalSeconds
timer.SetCommunicator(MPI::COMM_WORLD);

// once the choice is made, it will use the asked timing system for all functions
// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with the retrieved number
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// if you want to know the sum of elapsed times for all involved processors
// you retrieve also the minimum and maximum
double dt_loc, dt_sum, dt_min, dt_max;
timer.GetGlobalSeconds("Product", dt_loc, dt_sum, dt_min, dt_max);

Location :

Reset

Syntax :

  void Reset(int n);
  void Reset(const string& name);

This method resets the timer (identified either with a number or a string), i.e. the elapsed time is set to 0 for this timer.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with its name for example
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// if you start again the timer, the time is incremented
timer.Start("Product");

// other operations
...

// final stop
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset("Product");

Location :

Start

Syntax :

  void Start(int n);
  void Start(const string& name);

This method starts the timer (identified either with a number or a string). The elapsed time is incremented.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with its name
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// if you start again the timer, the time is incremented
timer.Start("Product");

// other operations
...

// final stop
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset("Product");

Location :

Stop

Syntax :

  void Stop(int n);
  void Stop(const string& name);

This method stops the timer (identified either with a number or a string). The elapsed time is updated only when this method is called.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with its name
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// if you start again the timer, the time is incremented
timer.Start("Product");

// other operations
...

// final stop
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset("Product");

Location :

GetSeconds

Syntax :

  double GetSeconds(int n);
  double GetSeconds(const string& name);

This method returns the elapsed time between a call to Stop and a call to Start. The elapsed time is updated only when the method Stop is called.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with its name
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// if you start again the timer, the time is incremented
timer.Start("Product");

// other operations
...

// final stop
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset("Product");

Location :

SetMessage

Syntax :

  void SetMessage(const string& name, const string& message);

This method creates a new timer associated with the string name. If a timer with the same name already exists, this method will just modify the message associated with the timer. A message is also required, this message is used when elapsed times are displayed with the method DisplayTime.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with its name
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// if you start again the timer, the time is incremented
timer.Start("Product");

// other operations
...

// final stop
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// if you want to reuse the timer, but restart from 0 seconds :
timer.Reset("Product");

Location :

ReleaseName

Syntax :

  void ReleaseName(const string& name);

This method destroys the timer associated with the string name.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create a new timer
timer.SetMessage("Product", "Perform this operation");

// then you can start the timer with its name
timer.Start("Product");

// perform operations
...

// then stop the timer
timer.Stop("Product");

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// once you no longer need this timer, you can release its name
timer.ReleaseName("Product");

Location :

ReserveName

Syntax :

  void ReserveName(const string& name);

This method creates a new timer associated with the string name. If a timer already exists with this name, the program is aborted.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create timers without specifying a message
timer.ReserveName("Product");
timer.ReserveName("Factorize");

// the message can be set afterwards
timer.SetMessage("Product", "perform the matrix vector product");

// then you can start the wished timer
timer.Start("Product");

// perform operations
...

// then stop the timer
timer.Stop("Product");

timer.Start("Factorize");

// perform operations
...

// then stop the timer
timer.Stop("Factorize");

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds("Product") << endl;
cout << "Time spent = " << timer.GetSeconds("Factorize") << endl;

Location :

NameExists

Syntax :

  bool NameExists(const string& name);

This method returns true if a timer with a given name already exists.

Example :

// object containing a set of timers
MontjoieTimer timer;

// if you want to create timers without specifying a message
timer.ReserveName("Product");
timer.ReserveName("Factorize");

// you can test the existence of a timer
if (timer.NameExists("Product"))
  cout << "Timer Product exists" << endl;

// the message can be set afterwards
timer.SetMessage("Product", "perform the matrix vector product");

// then you can start the wished timer
timer.Start("Product");

// perform operations
...

// then stop the timer
timer.Stop("Product");

timer.Start("Factorize");

// perform operations
...

// then stop the timer
timer.Stop("Factorize");

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds("Product") << endl;
cout << "Time spent = " << timer.GetSeconds("Factorize") << endl;

Location :

GetGlobalSeconds

Syntax :

  void GetGlobalSeconds(int n, double& dt_loc, double& dt_sum, double& dt_min, double& dt_max);
  void GetGlobalSeconds(const string& name, double& dt_loc, double& dt_sum, double& dt_min, double& dt_max);

This method retrieves the local time elapsed (i.e. time elapsed on the current processor), the sum of elapsed times on all processors, the maximal time among all processors, and minimal time. The timer is given through its name or its identification number.

Example :

// object containing a set of timers
MontjoieTimer timer;

// the choice of the timer can be changed before creating timers
timer.SetTimer(MontjoieTimer::ACCURATE_TIMER);

// the communicator can be set anywhere before a call to GetGlobalSeconds
timer.SetCommunicator(MPI::COMM_WORLD);

// once the choice is made, it will use the asked timing system for all functions
// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with the retrieved number
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// if you want to know the sum of elapsed times for all involved processors
// you retrieve also the minimum and maximum
double dt_loc, dt_sum, dt_min, dt_max;
timer.GetGlobalSeconds("Product", dt_loc, dt_sum, dt_min, dt_max);

Location :

DisplayTime

Syntax :

  void DisplayTime(int n);
  void DisplayTime(const string& name);

  void DisplayTime(int n, const string& message);
  void DisplayTime(const string& name, const string& message);

This method displays the elapsed time for a given timer (either by giving its number n or its name). The message can be given as a second argument, otherwise the displayed message will be the message given when SetMessage has been called.

Example :

// object containing a set of timers
MontjoieTimer timer;

// the choice of the timer can be changed before creating timers
timer.SetTimer(MontjoieTimer::ACCURATE_TIMER);

// the communicator can be set anywhere before a call to GetGlobalSeconds/DisplayTime
timer.SetCommunicator(MPI::COMM_WORLD);

// once the choice is made, it will use the asked timing system for all functions
// if you want to create a new timer with a string
timer.SetMessage("Product", "Perform the matrix vector product");

// then you can start the timer with the retrieved number
timer.Start("Product");

// perform operations
Matrix<double> A; Vector<double> x, b;
Mlt(A, x, b);

// then stop the timer
timer.Stop("Product");

// and display the elapsed time (it will be the sum of Stop - Start)
cout << "Time spent = " << timer.GetSeconds("Product") << endl;

// for a nice display (and with parallel information)
timer.DisplayTime("Product");

// if you want to specify another message
timer.DisplayTime("Product", "Perform my product");

Location :

DisplayAll

Syntax :

  void DisplayAll();

This method displays the elapsed times for all the created timers (through the methods ReserveName or SetMessage). The timers created with GetNumber/ReserveNumber are not displayed since they do not have a name.

Example :

// object containing a set of timers
MontjoieTimer timer;

// the communicator can be set anywhere before a call to DisplayAll
timer.SetCommunicator(MPI::COMM_WORLD);

// if you want to create timers without specifying a message
timer.ReserveName("Product");
timer.ReserveName("Factorize");

// the message can be set afterwards
timer.SetMessage("Product", "perform the matrix vector product");

// then you can start the wished timer
timer.Start("Product");

// perform operations
...

// then stop the timer
timer.Stop("Product");

timer.Start("Factorize");

// perform operations
...

// then stop the timer
timer.Stop("Factorize");

// and display the elapsed time
cout << "Time spent = " << timer.GetSeconds("Product") << endl;
cout << "Time spent = " << timer.GetSeconds("Factorize") << endl;

// if you want to do that automatically (display elapsed times for all timers)
timer.DisplayAll();

Location :