grids Module Reference

This module provides convenience routines to create grids Description: Submodule Arrays. More...

Functions/Subroutines
real(dp) function, dimension(num), public	linspace (start, end, num, endpoint, retstep)
real(dp) function, dimension(num), public	logspace (start, end, num, endpoint, base)
	Makes a grid with numbers spaced evenly on a log scale.
real(dp) function, dimension(num), public	geomspace (start, end, num, endpoint)
	Makes a grid with numbers spaced evenly on a log scale.
real(dp) function, dimension(num), public	loglinspace (start, end, num, step, ratio)
	loglinspace Computes a grid that may behave as linearly or logarithmically spaced
integer function, dimension(:), allocatable, public	arange (start, end, step)
	arange: Return evenly spaced integer values within a given interval

Detailed Description

This module provides convenience routines to create grids Description: Submodule Arrays.

Function/Subroutine Documentation

arange()

integer function, dimension(:), allocatable, public arange	(	integer, intent(in)	start,
		integer, intent(in)	end,
		integer, intent(in), optional	step )

arange: Return evenly spaced integer values within a given interval

Values are generated within the half-open interval [start, end) (in other words, the interval including start but excluding end).

Parameters

[in]	start	the starting value of the interval.
[in]	end	the final value of the interval (not included)
[in]	step	Spacing between values.

Returns

A sequence of numbers spaced evenly

geomspace()

real(dp) function, dimension(num), public geomspace	(	real(dp), intent(in)	start,
		real(dp), intent(in)	end,
		integer, intent(in)	num,
		logical, intent(in), optional	endpoint )

Makes a grid with numbers spaced evenly on a log scale.

Note

: Is similar to logspace but with endpoints specified directly. Also accepts simultaneously negative start and end

Parameters

[in]	start	start is the starting value
[in]	end	end is the final value of
[in]	num	Number of samples to generate. Must
[in]	endpoint	If True, end is

Returns

A sequence of numbers spaced evenly on a log scale.

Examples:

  print '(4(f8.2,1x))', geomspace(1._dp, 1000._dp, num=4)
  ! gives:     1.00    10.00   100.00  1000.00
  print '(4(f8.2,1x))', geomspace(-1000._dp, -1._dp, num=4)
  ! gives: -1000.00  -100.00   -10.00    -1.00

References logspace().

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linspace()

real(dp) function, dimension(num), public linspace	(	real(dp), intent(in)	start,
		real(dp), intent(in)	end,
		integer, intent(in)	num,
		logical, intent(in), optional	endpoint,
		real(dp), intent(out), optional	retstep )

Parameters

[in]	start	The starting value of the
[in]	end	The end value of the sequence,
[in]	num	Number of samples to generate. Must
[in]	endpoint	If True, end is
[out]	retstep	If present, return

Returns

An array of uniformly spaced numbers

Examples:

  print "(5(f4.2,1x))", linspace(2._dp, 3.0_dp, num=5)
  ! Gives: 2.00 2.25 2.50 2.75 3.00
  print "(5(f4.2,1x))", linspace(2._dp, 3.0_dp, num=5, endpoint=.false.)
  ! Gives: 2.00 2.20 2.40 2.60 2.80
  print "(5(f4.2,1x))", linspace(2._dp, 3.0_dp, num=5, retstep=step)
  ! Gives: 2.00 2.25 2.50 2.75 3.00

References basic::zero.

Referenced by histograms::histogram(), and logspace().

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loglinspace()

real(dp) function, dimension(num), public loglinspace	(	real(dp), intent(in)	start,
		real(dp), intent(in)	end,
		integer, intent(in)	num,
		real(dp), intent(in), optional	step,
		real(dp), intent(in), optional	ratio )

loglinspace Computes a grid that may behave as linearly or logarithmically spaced

From package RADIAL by Salvat et al 1995 Computer Physics Communications. The grid is such that:

1. R(1)=0, R(NP)=RN,
2. A*R(I)+B*log(R(I))-C= I (I > 0), with A=1/STEP and B=1/log(RATIO).

   Parameters

   [in]	start	Starting value
   [in]	end	Final value of the sequence
   [in]	num	Number of points
   [in]	step	Approximated step in the linear region
   [in]	ratio	quotient between consecutive points in the logarithmic region

   Returns

   Array of points with the grid of dimension num

   Examples:

  xmin = 1.e-4_dp; xmax = 10._dp
  ratio = 1.15_dp; steps = [0.125_dp, 0.25_dp, 0.5_dp, 1._dp]
  v = loglinspace(xmin, xmax, 50, step=0.4_dp, ratio=1.15_dp)

logspace()

real(dp) function, dimension(num), public logspace	(	real(dp), intent(in)	start,
		real(dp), intent(in)	end,
		integer, intent(in)	num,
		logical, intent(in), optional	endpoint,
		real(dp), intent(in), optional	base )

Makes a grid with numbers spaced evenly on a log scale.

In linear space, the sequence starts at base**start (base to the power of start) and ends with base**end

Parameters

[in]	start	base**start is the starting value of the sequence.
[in]	end	base**end is the final value of the sequence.
[in]	num	Number of samples to generate. Must be positive.
[in]	endpoint	If True, end is the last sample. Otherwise, it is not included. Default is True
[in]	base	The base of the log space. Default is 10.

Returns

A sequence of numbers spaced evenly on a log scale.

Examples:

  print '(4(f8.2,1x))', logspace(2._dp, 3.0_dp, num=4)
  ! gives:  100.00   215.44   464.16  1000.00
  print '(4(f8.2,1x))', logspace(2.0_dp, 3.0_dp, num=4, base=2.0_dp)
  ! gives:    4.00     5.04     6.35     8.00
  print '(4(f8.2,1x))', logspace(3._dp, zero, 4)
  ! gives: 1000.00   100.00    10.00     1.00

References linspace().

Referenced by geomspace().

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