stdlib_math.md

title
math

The stdlib_math module

[TOC]

Introduction

stdlib_math module provides general purpose mathematical functions.

Procedures and Methods provided

clip function

Description

Returns a value which lies in the given interval [xmin, xmax] (interval is xmin and xmax inclusive) and is closest to the input value x.

Syntax

res = [[stdlib_math(module):clip(interface)]] (x, xmin, xmax)

Status

Experimental

Class

Elemental function.

Argument(s)

x: scalar of either integer or real type. This argument is intent(in). xmin: scalar of either integer or real type. This argument is intent(in). xmax: scalar of either integer or real type, which must be greater than or equal to xmin. This argument is intent(in).

Note: All arguments must have same type and same kind.

Output value or Result value

The output is a scalar of type and kind same as to that of the arguments.

Examples

Example 1:

Here inputs are of type integer and kind int32

program demo_clip_integer
  use stdlib_math, only: clip
  use stdlib_kinds, only: int32
  implicit none
  integer(int32) :: x
  integer(int32) :: xmin
  integer(int32) :: xmax
  integer(int32) :: clipped_value

  xmin = -5_int32
  xmax = 5_int32
  x = 12_int32

  clipped_value = clip(x, xmin, xmax)
  ! clipped_value <- 5
end program demo_clip_integer

Example 2:

Here inputs are of type real and kind sp

program demo_clip_real
  use stdlib_math, only: clip
  use stdlib_kinds, only: sp
  implicit none
  real(sp) :: x
  real(sp) :: xmin
  real(sp) :: xmax
  real(sp) :: clipped_value

  xmin = -5.769_sp
  xmax = 3.025_sp
  x = 3.025_sp

  clipped_value = clip(x, xmin, xmax)
  ! clipped_value <- 3.02500010
end program demo_clip_real

linspace - Create a linearly spaced rank one array

Description

Returns a linearly spaced rank 1 array from [start, end]. Optionally, you can specify the length of the returned array by passing n.

Syntax

res = [[stdlib_math(module):linspace(interface)]] (start, end [, n])

Status

Experimental

Class

function.

Argument(s)

start: Shall be scalar of any numeric type. This argument is intent(in). end: Shall be the same type and kind as start. This argument is intent(in). n: Shall be an integer specifying the length of the output. This argument is intent(in).

Output value or Result value

The output is a rank 1 array of type and kind, whose length is either 100 (default value) or n.

If n == 1, return a rank 1 array whose only element is end. If n <= 0, return a rank 1 array with length 0

Examples

Example 1:

Here inputs are of type complex and kind dp

program demo_linspace_complex
  use stdlib_math, only: linspace
  use stdlib_kinds, only: dp
  implicit none

  complex(dp) :: start = complex(10.0_dp, 5.0_dp)
  complex(dp) :: end = complex(-10.0_dp, 15.0_dp)

  complex(dp) :: z(11)

  z = linspace(start, end, 11)
end program demo_linspace_complex

Example 2:

Here inputs are of type integer and kind int16

program demo_linspace_int16
  use stdlib_math, only: linspace
  use stdlib_kinds, only: int16
  implicit none

  integer(int16) :: start = 10_int16
  integer(int16) :: end = 23_int16

  integer(int16) :: r(15)

  r = linspace(start, end, 15)
end program demo_linspace_int16

logspace - Create a logarithmically spaced rank one array

Description

Returns a logarithmically spaced rank 1 array from [base^start, base^end]. Optionally, you can specify the length of the returned array by passing n.

Syntax

res = [[stdlib_math(module):logspace(interface)]] (start, end [, n [, base]])

Status

Experimental

Class

function.

Argument(s)

start: Shall be scalar of any numeric type. This argument is intent(in). end: Shall be the same type and kind as start. This argument is intent(in). n: Shall be an integer specifying the length of the output. This argument is intent(in). base : Shall be a scalar of any numeric type. This argument is intent(in)

Output value or Result value

The output is a rank 1 array of type and kind, whose length is either 50 (default value) or n.

If n == 1, return a rank 1 array whose only element is base^end. If n <= 0, return a rank 1 array with length 0

Examples

Example 1:

Here inputs are of type complex and kind dp

program demo_logspace_complex
  use stdlib_math, only: logspace
  use stdlib_kinds, only: dp
  implicit none

  complex(dp) :: start = complex(10.0_dp, 5.0_dp)
  complex(dp) :: end = complex(-10.0_dp, 15.0_dp)

  complex(dp) :: z(11)

  z = logspace(start, end, 11)
end program demo_logspace_complex

Example 2:

Here inputs are of type integer and kind int16

program demo_logspace_int16
  use stdlib_math, only: logspace
  use stdlib_kinds, only: int16
  implicit none

  integer(int16) :: start = 10_int16
  integer(int16) :: end = 23_int16

  integer(int16) :: r(15)

  r = logspace(start, end, 15)
end program demo_logspace_int16