DrawFromDistri.f90 File Reference

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Functions/Subroutines
subroutine	drawfromdistri (n, p, ix)
	DrawFromDistri
subroutine	drawfrompoissondist (mu, x, randomvalue)
	DrawFromPoissonDist
subroutine	drawfrombinomdist (n, p, x, randomvalue)
	DrawFromBinomDist
subroutine	drawfromnormaldist (mu, s, rx, randomvalue)
	DrawFromNormalDist

Function/Subroutine Documentation

drawfrombinomdist()

subroutine drawfrombinomdist	(	integer, intent(in)	n,
		real, intent(in)	p,
		integer, intent(out)	x,
		real, intent(in)	randomvalue )

DrawFromBinomDist

---

Samples from a binomial distribution.

• binomial distribution density: (n!/(i!(n-i)!)) * p**i (1-p)**(n-i).
• it is solved iteratively.

IN:

• Parameters

  n	: sample size
  p	: probability
  randomvalue	: random value

OUT:

• Parameters

  x	: drawn value

CALLS:

• RANDOM_NUMBER from FORTRAN

CALLED FROM:!> - DrawFromDistri in Interact.f90

Definition at line 160 of file DrawFromDistri.f90.

drawfromdistri()

subroutine drawfromdistri	(	integer, intent(in)	n,
		real, intent(in)	p,
		integer, intent(out)	ix )

DrawFromDistri

---

samples from a binomial distribution

1. for large sample sizes n, the binomial distribution is approximated by
   1. a Poisson distribution, if small probability
   2. a normal distribution, if larger probability
2. otherwise the binomial distribution is explicitly calculated

USE: All_par

• IN:

  • Parameters

    n	: sample size
    p	: probabilitxy

• OUT:
  

  • Parameters

    ix	: drawn value

• CALLS:
  • DrawFromPoissonDist in DrawFromDistri.f90
  • DrawFromBinomDist in DrawFromDistri.f90
  • DrawFromNormalDist in DrawFromDistri.f90
  • RANDOM_NUMBER from FORTRAN
• CALLED FROM:
  • SeedsDispersedFromThisCellAndSpec in Interact.f90

Definition at line 50 of file DrawFromDistri.f90.

drawfromnormaldist()

subroutine drawfromnormaldist	(	real, intent(in)	mu,
		real, intent(in)	s,
		real, intent(out)	rx,
		real, intent(in)	randomvalue )

DrawFromNormalDist

---

Samples from a normal distribution

1. uses a pre-stored array of the standard normal distribution
2. gets the value of the standard normal distribution by interpolating from this array
3. then transforms with the given mean and standard deviation

• IN:

  • Parameters

    mu	: mean
    s	: standard deviation
    randomvalue	: random value

• OUT:
  

  • Parameters

    rx	: drawn value

• CALLS:
  • RANDOM_NUMBER from FORTRAN
• CALLED FROM:!> - DrawFromDistri in Interact.f90
  • GetVariate in GetBioclim.f90

Definition at line 214 of file DrawFromDistri.f90.

drawfrompoissondist()

subroutine drawfrompoissondist	(	real, intent(in)	mu,
		integer, intent(out)	x,
		real, intent(in)	randomvalue )

DrawFromPoissonDist

---

Samples from a poisson distribution

• density function: P(i,mu)= exp(-mu) * (mu^i)/i!
• solved iteratively

IN:

• Parameters

  mu	: mean
  randomvalue	: random value

OUT:

• Parameters

  x	: drawn value

CALLS:

• RANDOM_NUMBER from FORTRAN

CALLED FROM:

• DrawFromDistri in Interact.f90

Definition at line 110 of file DrawFromDistri.f90.