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cummin(), cummax()

Cumulative minima and maxima of array's values
(200 downloads for this version - 200 downloads for all versions)
Details
Version
1.0
Author
Samuel Gougeon
Maintainer
Samuel Gougeon
License
Supported Scilab Version
5.0
Creation Date
May 25, 2015
Description
            cummin(..) and cummax(..) functions

-->cummax
function [R] = cummax(A,orien,fromlast)

 Cumulative maxima of values in a vector, matrix or hypermatrix

 CALLING SEQUENCES
 cummax           // displays this help
 cummax demo ;    // runs a randomized demo
 R = cummax(A)
 R = cummax(A, orien)
 R = cummax(A, orien, fromlast)

 PARAMETERS
 A, R : vector, matrix or hypermatrix of decimals, complex numbers, encoded
        integers, or booleans. R gets the sizes and the type of A.

 orien: 'r' | 1 | 'c' | 2 | n>2: the index of the dimension across which A
        must be processed. 'r' or 1 means across rows ; 'c' or 2 means
        across columns ; if A is an hypermatrix  with N dimensions, any
        integer N>= n > 2 means across the dimension #n. Default value =1

 fromlast: optional scalar boolean (default %F). If it is true, the processing
        starts from the last element across the chosen orientation, instead
        of starting from the first one.

 DESCRIPTION
 With R = cummax(A) or R = cummax(A,1) or R = cummax(A,"r"):
  For all columns, pages etc, the line #i of R takes the maximal value met
   across lines #1 to #i of A.
  If the option fromlast is %T, the line #i of R takes the maximal value met
   across lines #i to #$ of A (where $ stands for the index of the last line).
  If A is boolean, %T is considered as 1 and %F is considered as 0.
  If A contains complex numbers, numbers with maximal moduli are retained ;
   in case of equal moduli, numbers with maximal phases are retained.

 With R = cummax(A, 'c') or R = cummax(A, 2): A is processed accros columns:
  For all lines, pages, etc, the column #i of R takes the maximal value met
   across columns #1 to #i of A.

 EXAMPLES
 --------
// DECIMAL NUMBERS
-->a = grand(3,5,"uin",0,4)
 a  = [
    0.    0.    1.    2.    3.
    4.    1.    0.    3.    2.
    0.    4.    3.    2.    0.
    ]
-->cummax(a)
 ans  =
    0.    0.    1.    2.    3.
    4.    1.    1.    3.    3.
    4.    4.    3.    3.    3.

-->cummax(a,2, fromlast=%t)
 ans  =
    3.    3.    3.    3.    3.
    4.    3.    3.    3.    2.
    4.    4.    3.    2.    0.

// ENCODED INTEGERS
-->a = int8(a)
 a  =
  0  0  1  2  3
  4  1  0  3  2
  0  4  3  2  0

-->cummax(a,1, fromlast=%t)
 ans  =
  4  4  3  3  3
  4  4  3  3  2
  0  4  3  2  0

// BOOLEANS
-->a = a>2
 a  =
  F F F F T
  T F F T F
  F T T F F

-->cummax(a)
 ans  =
  F F F F T
  T F F T T
  T T T T T

// COMPLEX NUMBERS
-->c = grand(3,4,"uin",-2,2) + %i*grand(3,4,"uin",-2,2)
 c  =
    1. + i      1. - i      1. + i      i
    1. + i      0           1. + 2.i    1. + 2.i
    1. - i    - 2.        - 1. + i    - 2. - i

-->phases = atan(imag(c),real(c))
 phases  =
    0.7853982  - 0.7853982    0.7853982    1.5707963
    0.7853982    0.           1.1071487    1.1071487
  - 0.7853982    3.1415927    2.3561945  - 2.677945

-->cummax(c)
 ans  =
    1. + i      1. - i      1. + i      i
    1. + i      1. - i      1. + 2.i    1. + 2.i
    1. + i    - 2.          1. + 2.i    1. + 2.i

 // HYPERMATRIX:
-->a = int8(grand(2,4,3,"uin",0,4))
 a  =
(:,:,1)
  3  1  2  3
  1  2  2  2
(:,:,2)
  4  1  0  3
  1  3  1  1
(:,:,3)
  0  4  2  0
  4  4  0  3

-->cummax(a,3)
 ans  =
(:,:,1)
  3  1  2  3
  1  2  2  2
(:,:,2)
  4  1  2  3
  1  3  2  2
(:,:,3)
  4  4  2  3
  4  4  2  3

// ===========================================================

-->cummin
function [R] = cummin(A,orien,fromlast)

 Cumulative minima of values in a vector, matrix or hypermatrix

 CALLING SEQUENCES
 cummin           // displays this help
 cummin demo ;    // runs a randomized demo
 R = cummin(A)
 R = cummin(A, orien)
 R = cummin(A, orien, fromlast)

 PARAMETERS
 A, R : vector, matrix or hypermatrix of decimals, complex numbers, encoded
        integers, or booleans. R gets the sizes and the type of A.

 orien: 'r' | 1 | 'c' | 2 | n>2: the index of the dimension across which A
        must be processed. 'r' or 1 means across rows ; 'c' or 2 means
        across columns ; if A is an hypermatrix  with N dimensions, any
        integer N>= n > 2 means across the dimension #n. Default value =1

 fromlast: optional scalar boolean (default %F). If it is true, the processing
        starts from the last element across the chosen orientation, instead
        of starting from the first one.

 DESCRIPTION
 With R = cummin(A) or R = cummin(A,1) or R = cummin(A, 'r'):
  For all columns, pages etc, the line #i of R takes the minimal value met
   across lines #1 to #i of A.
  If the option fromlast is %T, the line #i of R takes the minimal value met
   across lines #i to #$ of A (where $ stands for the index of the last line).
  If A is boolean, %T is considered as 1 and %F is considered as 0.
  If A contains complex numbers, numbers with minimal moduli are retained ;
   in case of equal moduli, numbers with minimal phases are retained.

 With R = cummin(A, 'c') or R = cummin(A, 2): A is processed accros columns:
  For all lines, pages, etc, the column #i of R takes the minimal value met
   across columns #1 to #i of A.

 SEE ALSO: cummax

 EXAMPLES
 --------
-->a = int8(grand(3,4,"uin",0,5))
 a  = [
  4  3  5  2
  2  1  4  4
  1  0  5  3
  ]
-->cummin(a)
 ans  =
  4  3  5  2
  2  1  4  2
  1  0  4  2

-->cummin(a, 2)
 ans  =
  4  3  3  2
  2  1  1  1
  1  0  0  0

-->cummin(a, 2, fromlast=%t)
 ans  =
  2  2  2  2
  1  1  4  4
  0  0  3  3
            
Files (1)
[12.90 kB]
Miscellaneous file
Macro defining both cummin() and cummax() functions

* MAKE IT AVAILABLE in EVERY SESSION: Click there to see indications

* Get help: Enter "cummin" or "cummax" without parameters 

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