aGrUM  0.13.2

All the maths you'll need. More...

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## Detailed Description

All the maths you'll need.

## Classes

class  gum::Formula
Evaluates a string as a algebraic formula. More...

class  gum::Chi2
Represent the chi2 distribution. More...

class  gum::Dirichlet
A class for sampling w.r.t. More...

class  gum::FormulaPart
Represents part of a formula. More...

class  gum::GammaLog2
The class for computing Log2 (Gamma(x)) More...

class  gum::Rational< GUM_SCALAR >
Class template used to approximate decimal numbers by rationals. More...

## Integers Pow utility methods

unsigned long gum::intPow (unsigned long base, unsigned long exponent)
Specialized pow function with integers (faster implementation). More...

unsigned long gum::int2Pow (unsigned long exponent)
Specialized base 2 pow function with integer. More...

void gum::superiorPow (unsigned long card, unsigned long &num_bits, unsigned long &new_card)
Compute the superior and closest power of two of an integer. More...

## Function Documentation

 INLINE unsigned long gum::int2Pow ( unsigned long exponent )

Specialized base 2 pow function with integer.

Parameters
 exponent The unsigned long integer exponent used to compute $$2^{exponent}$$ which will hold the result of afterward.

Definition at line 46 of file pow_inl.h.

46 { return 1UL << exponent; }

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 INLINE unsigned long gum::intPow ( unsigned long base, unsigned long exponent )

Specialized pow function with integers (faster implementation).

Parameters
 base The constant unsigned long integer base used to compute $$base^{exponent}$$. exponent The unsigned long integer exponent used which will hold the result afterward.

Definition at line 33 of file pow_inl.h.

33  {
34  if (exponent == 0) { return 1UL; }
35
36  unsigned long out = base;
37
38  for (unsigned long i = 1; i < exponent; i++)
39  out *= base;
40
41  return out;
42  }

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 INLINE void gum::superiorPow ( unsigned long card, unsigned long & num_bits, unsigned long & new_card )

Compute the superior and closest power of two of an integer.

Given an integer, compute it's - superior - and closest power of two, i.e. the number of bits necessary to represent this integer as well as the maximum integer that can be represented by those bits.

Parameters
 card The constant unsigned long integer we wish to represent by bits. num_bits The unsigned long integer used as a "return" value to get the minimum number of bits used to represend card. new_card The unsigned long integer used as a "return" value to get the maximum number those bits can represent, i.e. $$2^{num\_bits}$$.

Definition at line 52 of file pow_inl.h.

54  {
55  if (card == 0) {
56  num_bits = 0;
57  new_card = 1;
58  return;
59  }
60
61  num_bits = 1;
62  new_card = 2;
63
64  while (new_card < card) {
65  new_card *= 2;
66  num_bits++;
67  }
68  }

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