./../../src/utilities.lsp

## sc/utilities [ Modules ]

[ Top ] [ Modules ]

NAME

     utilities

     File:             utilities.lsp

     Class Hierarchy:  none: no classes defined

     Version:          1.0.3

     Project:          slippery chicken (algorithmic composition)

     Purpose:          Various helper functions of a general nature.

     Author:           Michael Edwards: m@michael-edwards.org

     Creation date:    June 24th 2002

     $$ Last modified: 21:40:20 Sat Jun 22 2013 BST

     SVN ID: $Id: utilities.lsp 4065 2013-06-24 10:24:06Z medward2 $

## utilities/all-members [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Find out whether the members of the list given as the second argument are
     all present in the list given as the first argument.

ARGUMENTS

     - A list in which the members of the second argument will be sought.
     - A list whose members will be sought in the first argument.

     OPTIONAL ARGUMENT
     - A comparison function.

RETURN VALUE

     T or NIL.

EXAMPLE

    (all-members '(1 2 3 4 5 6 7) '(1 2 3 7))

    => T

SYNOPSIS

    (defun all-members (list test-list &optional (test #'equal))

## utilities/almost-zero [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return T if a given decimal is within 0.000001 of 0.0.

ARGUMENTS

     - A number.

OPTIONAL ARGUMENTS

     - A number that is a user-specified difference for the comparison test.

RETURN VALUE

     T if the number is within the tolerance difference to zero, otherwise NIL.

EXAMPLE

    (almost-zero 0.0000007)

    => T

SYNOPSIS

    (defun almost-zero (num &optional (tolerance 0.000001))

## utilities/amp2db [ Methods ]

[ Top ] [ utilities ] [ Methods ]

DESCRIPTION

     Convert a standard digital amplitude value (>0.0 to 1.0) to a corresponding
     decibel value.

ARGUMENTS

     - A decimal number between >0.0 and 1.0.

RETURN VALUE

     A decimal number that is a value in decibel.

EXAMPLE

    (amp2db 0.3)

    => -10.457575

SYNOPSIS

    (defmacro amp2db (amp)

## utilities/amplitude-to-dynamic [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Convert a specified digital amplitude between 0.0 and 1.0 to a
     corresponding dynamic between niente and ffff.

ARGUMENTS

     - A decimal number between 0.0 and 1.0.

OPTIONAL ARGUMENTS

     - T or NIL to indicate whether to print a warning if the specified
       amplitude is <0.0 or >1.0. T = warn. Default = T.

RETURN VALUE

     A symbol that is a dynamic level.

EXAMPLE

    (amplitude-to-dynamic 0.3)

    => PP

SYNOPSIS

    (defun amplitude-to-dynamic (amp &optional (warn t))

## utilities/between [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return a random number between two specified numbers. If the two numbers
     are integers, the random selection is inclusive. If they are decimal
     numbers, the result cannot be absolutely inclusive.

ARGUMENTS

     - A first, lower, number.
     - A second, higher, number.

     NB: The first number must always be lower than the second.

OPTIONAL ARGUMENTS

     - T or NIL to indicate whether the random seed should be fixed.
     - If fixed-random is set to T, a function must be given for <restart> to
       reset the seed (see below)

RETURN VALUE

     An integer if both numbers are integers, or a float if one or both are
     decimal numbers.

EXAMPLE

    ;;; Using the defaults. This will produce a different result each time.
    (loop repeat 10 collect (between 1 100))

    => (43 63 26 47 28 2 99 93 66 23)

    ;;; Setting fixed-random to T and using zerop to reset the random when i is 0
    (loop repeat 5
       collect (loop for i from 0 to 9 collect (between 1 100 t (zerop i))))

    => ((93 2 38 81 43 19 70 18 44 26) (93 2 38 81 43 19 70 18 44 26)
        (93 2 38 81 43 19 70 18 44 26) (93 2 38 81 43 19 70 18 44 26)
        (93 2 38 81 43 19 70 18 44 26))

SYNOPSIS

    (defun between (low high &optional fixed-random restart)

## utilities/combine-into-symbol [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Combine a sequence of elements of any combination of type string, number,
     or symbol into a symbol.

ARGUMENTS

     - A sequence of elements.

RETURN VALUE

     A symbol as the primary value, with the length of that symbol as a
     secondary value.

EXAMPLE

    (combine-into-symbol "test" 1 'a)

    => TEST1A, 6

SYNOPSIS

    (defun combine-into-symbol (&rest params)

## utilities/db2amp [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Convert a decibel value to a standard digital amplitude value (>0.0 to 1.0),
     whereby 0dB = 1.0.

ARGUMENTS

     - A number that is a value in decibel.

RETURN VALUE

     A decimal number between >0.0 and 1.0.

EXAMPLE

    (db2amp -3)

    => 0.70794576

SYNOPSIS

    (defmacro db2amp (db)

## utilities/decimal-places [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DATE

     19-Mar-2012

DESCRIPTION

     Round the given number to the specified number of decimal places.

ARGUMENTS

     - A number.
     - An integer that is the number of decimal places to which to round the
       given number.

RETURN VALUE

     A decimal number.

EXAMPLE

    (decimal-places 1.1478349092347 2)

    => 1.15

SYNOPSIS

    (defun decimal-places (num places)

## utilities/dynamic-to-amplitude [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Convert a symbol that is a dynamic level between niente and ffff to a
     corresponding digital amplitude value between 0.0 and 1.0.

ARGUMENTS

     - A symbol that is a dynamic level between niente and fff.

OPTIONAL ARGUMENTS

     - T or NIL to indicate whether to print a warning when the symbol specified
       is not recognized as a dynamic. T = warn. Default = T.

RETURN VALUE

     A decimal number between 0.0 and 1.0.

EXAMPLE

    (dynamic-to-amplitude 'fff)

    => 0.9

SYNOPSIS

    (defun dynamic-to-amplitude (dynamic &optional (warn t))

## utilities/econs [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Add a specified element to the end of an existing list.

ARGUMENTS

     - A list.
     - An element to add to the end of the list.

RETURN VALUE

     A new list.

EXAMPLE

    (econs '(1 2 3 4) 5)

    =>  '(1 2 3 4 5)

SYNOPSIS

    (defun econs (list new-back)

## utilities/env-plus [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Increase all y values of a given list of break-point pairs by a specified
     amount.

ARGUMENTS

     - An envelope in the form of a list of break-point pairs.
     - A number that is the amount by which all y values of the given envelope
       are to be increased.

RETURN VALUE

     A list of break-point pairs.

EXAMPLE

    (env-plus '(0 0 25 11 50 13 75 19 100 23) 7.1)

    => (0 7.1 25 18.1 50 20.1 75 26.1 100 30.1)

SYNOPSIS

    (defun env-plus (env add)

## utilities/env-symmetrical [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Create a new list of break-point pairs that is symmetrical to the original
     around a specified center. If no center is specified, the center value
     defaults to 0.5

ARGUMENTS

     - An envelope in the form of a list of break-point pairs.

OPTIONAL ARGUMENTS

     - A number that is the center value around which the values of the
       new list are to be symmetrical.
     - A number that is to be the minimum value for the y values returned.
     - A number that is to be the maximum value for the y values returned.

RETURN VALUE

     An envelope in the form of a list of break-point pairs.

EXAMPLE

    ;;; Default center is 0.5
    (env-symmetrical '(0 0 25 11 50 13 75 19 100 23))

    => (0 1.0 25 -10.0 50 -12.0 75 -18.0 100 -22.0)

    ;; Specifying a center of 0
    (env-symmetrical '(0 0 25 11 50 13 75 19 100 23) 0)

    => (0 0.0 25 -11.0 50 -13.0 75 -19.0 100 -23.0)

    ;;; Specifying minimum and maximum y values for the envelope returned
    (env-symmetrical '(0 0 25 11 50 13 75 19 100 23) 0 -20 -7)

    => (0 -7 25 -11.0 50 -13.0 75 -19.0 100 -20)

SYNOPSIS

    (defun env-symmetrical (env &optional (centre .5)
                            (min most-negative-double-float)
                            (max most-positive-double-float))

## utilities/equal-within-tolerance [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Test whether the difference between two decimal numbers falls within a
     specified tolerance.

     This test is designed to compensate for calculation discrepancies caused by
     floating-point errors (such as 2.0 vs. 1.9999997), in which the equations
     should yield equal numbers. It is intended to be used in place of = in such
     circumstances.

ARGUMENTS

     - A first number.
     - A second number.

OPTIONAL ARGUMENTS

     - A decimal value that is the maximum difference allowed between the two
       numbers that will still return T. Default = 0.000001d0.

RETURN VALUE

     T if the two tested numbers are equal within the specified tolerance,
     otherwise NIL.

EXAMPLE

    ;; An example of floating-point error
    (loop for i from 0.0 below 1.1 by 0.1 collect i)

    => (0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.70000005 0.8000001 0.9000001 1.0000001)

    ;; Using =
    (loop for i from 0.0 below 1.1 by 0.1
       for j in '(0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0)
       collect (= i j))

    => (T T T T T T T NIL NIL NIL NIL)

    ;; Using equal-within-tolerance
    (loop for i from 0.0 below 1.1 by 0.1
       for j in '(0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0)
       collect (equal-within-tolerance i j))

    => (T T T T T T T T T T T)

SYNOPSIS

    (defun equal-within-tolerance (a b &optional (tolerance 0.000001d0))

## utilities/factor [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Boolean test to check if a specified number is a multiple of a second
     specified number.

ARGUMENTS

     - A number that will be tested to see if it is a multiple of the second
       number.
     - A second number that is the base number for the factor test.

RETURN VALUE

     T if the first number is a multiple of the second number, otherwise NIL.

EXAMPLE

    (factor 14 7)

    => T

SYNOPSIS

    (defun factor (num fac)

## utilities/flatten [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return a list of nested lists of any depth as a flat list.

ARGUMENTS

     - A list of nested lists.

RETURN VALUE

     A flat list.

EXAMPLE

    (flatten '((1 (2 3 4) (5 (6 7) (8 9 10 (11) 12)) 13) 14 15 (16 17)))

    => (1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17)

SYNOPSIS

    (defun flatten (nested-list)

## utilities/force-length [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DATE

     03-FEB-2011

DESCRIPTION

     Create a new a list of a specified new length by adding or removing items
     at regular intervals from the original list. If adding items and the list
     contains numbers, linear interpolation will be used, but only between two
     adjacent items; i.e. not with a partial increment.

     NB: The function can only create new lists that have a length between 1 and
         1 less than double the length of the original list.

ARGUMENTS

     - A flat list.
     - A number that is the new length of the new list to be derived from the
       original list. This number must be a value between 1 and 1 less than
       double the length of the original list.

RETURN VALUE

EXAMPLE

    ;;; Shortening a list
    (force-length (loop for i from 1 to 100 collect i) 17)

    => (1 7 13 20 26 32 39 45 51 57 63 70 76 82 89 95 100)

    ;;; Lengthening a list
    (force-length (loop for i from 1 to 100 collect i) 199)

    => (1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12
        12.5 13 13.5 14 14.5 15 15.5 16 16.5 17 17.5 18 18.5 19 19.5 20 20.5 21
        21.5 22 22.5 23 23.5 24 24.5 25 25.5 26 26.5 27 27.5 28 28.5 29 29.5 30
        30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36 36.5 37 37.5 38 38.5 39
        39.5 40 40.5 41 41.5 42 42.5 43 43.5 44 44.5 45 45.5 46 46.5 47 47.5 48
        48.5 49 49.5 50 50.5 51 51.5 52 52.5 53 53.5 54 54.5 55 55.5 56 56.5 57
        57.5 58 58.5 59 59.5 60 60.5 61 61.5 62 62.5 63 63.5 64 64.5 65 65.5 66
        66.5 67 67.5 68 68.5 69 69.5 70 70.5 71 71.5 72 72.5 73 73.5 74 74.5 75
        75.5 76 76.5 77 77.5 78 78.5 79 79.5 80 80.5 81 81.5 82 82.5 83 83.5 84
        84.5 85 85.5 86 86.5 87 87.5 88 88.5 89 89.5 90 90.5 91 91.5 92 92.5 93
        93.5 94 94.5 95 95.5 96 96.5 97 97.5 98 98.5 99 99.5 100)

SYNOPSIS

    (defun force-length (list new-len)

## utilities/get-harmonics [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return a list of the harmonic partial frequencies in Hertz from a
     specified (usually fundamental) frequency.

ARGUMENTS

     - A number that is the fundamental or starting frequency in Hertz.

OPTIONAL ARGUMENTS

     keyword arguments
     - :start-partial. An integer that is the number of the first harmonic
        partial to return. Default = 1.
     - :min-freq. A number that is the lowest frequency in Hertz to
       return. Default = 20.
     - :max-freq. A number that is the highest frequency in Hertz to
       return. Default = 20000.
     - :start-freq-is-partial.  Rather than treating the first argument as the
       fundamental, treat it as the partial number indicated by this argument.
       Default = 1.
     - :max-results.  The maximum number of harmonics to return.  Default =
        most-positive-fixnum

RETURN VALUE

     A list of numbers that are the frequencies in Hertz of harmonic partials
     above the same fundamental frequency.

EXAMPLE

    ;;; Get the first 15 harmonic partials above a fundamental pitch of 64 Hertz,
    ;;; starting with partial 2, and specifying an upper cut-off of 1010 Hz.

    (get-harmonics 63 :start-partial 2 :max-freq 1010)

    => (126 189 252 315 378 441 504 567 630 693 756 819 882 945 1008)

SYNOPSIS

    (defun get-harmonics (start-freq &key (start-partial 1) (min-freq 20)
                          (start-freq-is-partial 1) (max-freq 20000)
                          (max-results most-positive-fixnum))

## utilities/get-sublist-indices [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Get the starting position of sublists within a list as though the complete
     set of items were a flat list.

ARGUMENTS

     - A list of lists.

RETURN VALUE

     A list of integers that are the indices of the sublists.

EXAMPLE

    (get-sublist-indices '((1 2) (3 4 5 6) (7 8 9) (10 11 12 13 14) (15)))

    => (0 2 6 9 14)

SYNOPSIS

    (defun get-sublist-indices (list)

## utilities/get-sublist-lengths [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Get the lengths of all sublists in a given list.

ARGUMENTS

     - A list of lists.

OPTIONAL ARGUMENTS

     - T or NIL to indicate whether to first remove zeros caused by empty
       sublists from the result.

RETURN VALUE

     A list of integers.

EXAMPLE

    ;; Straightforward usage allows zeros in the result
    (get-sublist-lengths '((1 2) (3 4 5 6) (7 8 9) (10 11 12 13 14) ()))

    => (2 4 3 5 0)

    ;; Setting the optional argument to T removes zeros from the result

    (get-sublist-lengths '((1 2) (3 4 5 6) (7 8 9) (10 11 12 13 14) ()) t)

    => (2 4 3 5)

SYNOPSIS

    (defun get-sublist-lengths (list &optional (remove-zeros nil))

## utilities/hailstone [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Implementation of the Collatz conjecture (see
     http://en.wikipedia.org/wiki/Collatz_conjecture )

     The Collatz conjecture suggests that by starting with a given number, and
     if it is even dividing it by two or if it is odd multiplying it by three
     and adding one, then repeating with the new result, the process will
     eventually always result in one.

ARGUMENTS

     - A number to start with.

RETURN VALUE

     A list of the results collected from each iteration starting with the
     specified number and ending with one.

EXAMPLE

    (hailstone 11)

    => (11 34 17 52 26 13 40 20 10 5 16 8 4 2 1)

SYNOPSIS

    (defun hailstone (n)

## utilities/hz2ms [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Convert a frequency in Hertz to the equivalent number of milliseconds.

ARGUMENTS

     - A number that is a Hertz frequency.

RETURN VALUE

     A number that is the millisecond equivalent of the specified Hertz
     frequency.

EXAMPLE

    (hz2ms 261.63)

    => 3.8221915

SYNOPSIS

    (defun hz2ms (hertz)

## utilities/interpolate [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Get the interpolated value at a specified point within an envelope. The
     envelope must be specified in the form of a list of break-point pairs.

ARGUMENTS

     - A number that is the point within the specified envelope for which to
       return the interpolated value.
     - A list of break-point pairs.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :scaler. A number that is the factor by which to scale the values of
       the break-point pairs in the given envelope before retrieving the
       interpolated value. Default = 1.
     - :exp. A number that is the exponent to which the result should be
       raised. Default = 1.
     - :warn. T or NIL to indicate whether the method should print a warning if
       the specified point is outside of the bounds of the x-axis specified in
       the list of break-point pairs. T = warn. Default = T.

RETURN VALUE

EXAMPLE

    ;;; Using the defaults
    (interpolate 50 '(0 0 100 1))

    => 0.5

    ;;; Specifying a different scaler
    (interpolate 50 '(0 0 100 1) :scaler 2)

    => 1.0

    ;;; Specifying a different exponent by which the result is to be raised
    (interpolate 50 '(0 0 100 1) :exp 2)

    => 0.25

SYNOPSIS

    (defun interpolate (point env &key (scaler 1) (exp 1) (warn t))

## utilities/list-to-string [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Convert a list to a string.

ARGUMENTS

     - A list.

OPTIONAL ARGUMENTS

     - A string that will serve as a separator between the elements.
       Default = " ".
     - T or NIL to indicate whether a list value of NIL is to be returned as
       "NIL" or NIL. T = "NIL" as a string. Default = T.

RETURN VALUE

EXAMPLE

    ;;; Using defaults
    (list-to-string '(1 2 3 4 5))

    => "1 2 3 4 5"

    ;;; Specifying a different separator
    (list-to-string '(1 2 3 4 5) "-")

    => "1-2-3-4-5"

    ;;; A NIL list returns "NIL" as a string by default
    (list-to-string NIL)

    => "nil"

    ;;; Setting the second optional argument to NIL returns a NIL list as NIL
    ;;; rather than as "NIL" as a string
    (list-to-string NIL "" nil)

    => NIL

SYNOPSIS

    (defun list-to-string (list &optional (separator " ") (nil-as-string t))

## utilities/logarithmic-steps [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Create a list of progressing from the first specified argument to the
     second specified argument over the specified number of steps using an
     exponential curve rather than linear interpolation.

ARGUMENTS

     - A number that is the starting value in the resulting list.
     - A number that is the ending value in the resulting list.
     - An integer that will be the length of the resulting list - 1.

OPTIONAL ARGUMENTS

     - A number that will be used as the exponent when determining the
       exponential interpolation between values. Default = 2.

RETURN VALUE

     A list of numbers.

EXAMPLE

    (logarithmic-steps 1 100 19)

    => (1.0 1.3055556 2.2222223 3.75 5.888889 8.638889 12.0 15.972222 20.555555
        25.75 31.555555 37.97222 45.0 52.63889 60.88889 69.75 79.22222 89.30556
        100.0)

SYNOPSIS

    (defun logarithmic-steps (low high num-steps &optional (exponent 2))

## utilities/middle [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Get the number value that is middle of two number values.

ARGUMENTS

     - A first number.
     - A second number.

RETURN VALUE

     A number.

EXAMPLE

    (middle 7 92)

    => 49.5

SYNOPSIS

    (defun middle (lower upper)

## utilities/mins-secs-to-secs [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Derive the number of seconds from a minutes-seconds value that is indicated
     as a two-item list in the form '(minutes seconds).

ARGUMENTS

     - A two-item list of integers in the form '(minutes seconds).

RETURN VALUE

     A decimal number that is a number in seconds.

EXAMPLE

    (mins-secs-to-secs '(2 1))

    => 121.0

SYNOPSIS

    (defun mins-secs-to-secs (list)

## utilities/move-elements [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DATE

     02-Mar-2011

DESCRIPTION

     Move the specified elements from one list (if they are present in that
     list) to another, deleting them from the first.

ARGUMENTS

     - A list of elements that are the elements to be moved.
     - A list from which the specified elements are to be moved and deleted.
     - A list to which the specified elements are to be moved.

OPTIONAL ARGUMENTS

     - A predicate by which to test that the specified elements are equal to
       elements of the source list. Default = #'eq.

RETURN VALUE

     Two values: A first list that is the source list after the items have been
     moved; a second list that is the target list after the items have been
     moved.

EXAMPLE

    (move-elements '(3 5 8) '(1 2 3 4 5 6 7 8 9) '(a b c d e))

    => (1 2 4 6 7 9), (8 5 3 A B C D E)

SYNOPSIS

    (defun move-elements (what from to &optional (test #'eq))

## utilities/move-to-end [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DATE

     22-May-2011

DESCRIPTION

     Move a specified element of a given list to the end of the list, returning
     the new list.

     NB: If the element exists more than once in the given list, all but on of
         the occurrences will be removed and only one of them will be placed at
         the end.

ARGUMENTS

     - An item that is an element of the list that is the second argument.
     - A list.

RETURN VALUE

     A list.

EXAMPLE

    ;;; All unique items
    (move-to-end 2 '(1 2 3 4 5))

    => (1 3 4 5 2)

    ;;; Duplicate items
    (move-to-end 2 '(1 2 3 2 4 2 5))

    => (1 3 4 5 2)

SYNOPSIS

    (defun move-to-end (what list &optional (test #'eql))

## utilities/nconc-sublists [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Concatenate corresponding sublists of a given list. Each sublist in the
     argument should have the same length and number of sublists etc.

ARGUMENTS

     A list of lists.

RETURN VALUE

     A list of lists.

EXAMPLE

    (nconc-sublists '(((1 2) (a b) (cat dog))
                      ((3 4) (c d) (bird fish))
                      ((5 6) (e f) (pig cow))))

    => ((1 2 3 4 5 6) (A B C D E F) (CAT DOG BIRD FISH PIG COW))

SYNOPSIS

    (defun nconc-sublists (lists)

## utilities/nearest-power-of-2 [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return the closest number to the specified value that is a power of two but
     not greater than the specified value.

ARGUMENTS

     - A number.

RETURN VALUE

     An integer that is a power of two.

EXAMPLE

    (nearest-power-of-2 31)

    => 16

    (nearest-power-of-2 32)

    => 32

    (nearest-power-of-2 33)

    => 32

SYNOPSIS

    (defun nearest-power-of-2 (num)

## utilities/octave-freqs [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     A boolean test to determine whether two specified frequencies are octave
     transpositions of the same pitch class.

ARGUMENTS

     - A first number that is a frequency in Hertz.
     - A second number that is a frequency in Hertz.

OPTIONAL ARGUMENTS

     - T or NIL to indicate whether identical frequencies ("unison") are also
       to be considered octave transpositions of the same pitch class.
       T = unisons are also octaves. Default = T.

RETURN VALUE

     T or NIL.

EXAMPLE

    (octave-freqs 261.63 2093.04)

    => T

    (octave-freqs 261.63 3000.00)

    => NIL

    (octave-freqs 261.63 261.63)

    => T

    (octave-freqs 261.63 261.63 nil)

    => NIL

SYNOPSIS

    (defun octave-freqs (freq1 freq2 &optional (unison-also t))

## utilities/parse-audacity-label-file-for-loops [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Read an audacity label file and return its loop points as groups.

     NB: If this fails it's probably because there's a tab between time and
         label instead of spaces: save in emacs to detab.

     NB: Beware that marker files created on different operating systems from
         the one on which this function is called might trigger errors due to
         newline character mismatches.

ARGUMENTS

     - A string that is the name of the label file to be parsed, including
       directory path and extension.

RETURN VALUE

     Returns a list of lists which are the grouped time points.

     Also prints separate feedback to the listener.

EXAMPLE

    (parse-audacity-label-file-for-loops  "/path/to/24-7loops1.txt")

    =>
    313 markers, 50 loops read

    ((25.674559 25.829296 26.116327 26.649048 27.038843)
     (32.211884 32.33669 32.481815 32.618233 32.716915 32.902676 33.227757
      33.61959)
     (36.893604 37.059048 37.160633 37.27383 37.439274 37.4683 37.627937)
     (39.52907 39.81932 39.999275 40.2634 40.338867 40.605896)
     (45.612698 45.818775 46.050976 46.145306 46.275192)
     (46.4566 46.644535 46.76934 46.886894 46.971066 47.16553)
     (84.15927 84.260864 84.292786 84.355194 84.47274 84.52789 84.556915
      84.65415)
     ...
     (676.1075 676.79114 677.1503 677.57904 678.12366)
     (799.29205 799.8019 800.58984 800.96063 801.13446 801.45886)
     (804.98145 805.2016 805.5724 805.83887 806.31396))

SYNOPSIS

    (defun parse-audacity-label-file-for-loops (label-file)

## utilities/parse-wavelab-marker-file-for-loops [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Read a wavelab marker file and return its loop points as groups.

     The marker file must contain markers with the word "loop". A marker with
     that name will start a new set of loop points, and nameless markers will
     belong to the group until the next "loop" marker.

ARGUMENTS

     - A string that is the name of the marker file to be parsed, including
       directory path and extension.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :sampling-rate. An integer that is the sampling rate of the sound file to
       which the marker file refers. This value will affect the resulting time
       points. Default = 44100.
     - :max-length. The maximum duration in seconds between two points: anything
       greater than this will result in a warning being printed.

RETURN VALUE

     Returns a list of lists which are the grouped time points.

     Also prints separate feedback to the listener.

EXAMPLE

    (parse-wavelab-marker-file-for-loops "/path/to/24-7loops1.mrk")

    =>
    WARNING:
       utilities::parse-wavelab-marker-file-for-loops
       loop points 10:13.213 to 10:14.475 are too long (1.2620239)
    WARNING:
       utilities::parse-wavelab-marker-file-for-loops
       loop points 10:33.223 to 10:34.486 are too long (1.2630615)
    WARNING:
       utilities::parse-wavelab-marker-file-for-loops
       loop points 10:36.456 to 10:37.522 are too long (1.06604)

    312 markers, 50 loops read

    ((25.674559 25.829296 26.116327 26.649048 27.038843)
     (32.211884 32.33669 32.481815 32.618233 32.716915 32.902676 33.227757
      33.61959)
     (36.893604 37.059048 37.160633 37.27383 37.439274 37.4683 37.627937)
     (39.52907 39.81932 39.999275 40.2634 40.338867 40.605896)
     (45.612698 45.818775 46.050976 46.145306 46.275192)
     (46.4566 46.644535 46.76934 46.886894 46.971066 47.16553)
     (84.15927 84.260864 84.292786 84.355194 84.47274 84.52789 84.556915
      84.65415)
     ...
     (655.91077 656.4554 656.80304 657.4519 658.04285 658.8192)
     (676.1075 676.79114 677.1503 677.57904 678.12366)
     (799.29205 799.8019 800.58984 800.96063 801.13446 801.45886)
     (804.98145 805.2016 805.5724 805.83887 806.31396))

SYNOPSIS

    (defun parse-wavelab-marker-file-for-loops
        (marker-file &key (sampling-rate 44100) (max-length 1.0))

## utilities/partial-freqs [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DATE

     13-Dec-2011

DESCRIPTION

     A Boolean test to determine whether either of two specified frequencies
     can be considered a harmonic partial of the other.

ARGUMENTS

     - A first frequency in Hertz.
     - A second frequency in Hertz.

OPTIONAL ARGUMENTS

     - T or NIL to indicate whether identical frequencies ("unison") are also to
       be considered partials of each other. T = unison are partials.
       Default = T.

RETURN VALUE

     T if one of the frequencies has the ratio of a harmonic partial to the
     other, otherwise NIL.

EXAMPLE

    (partial-freqs 300 900)

    => T

    (partial-freqs 300 700)

    => NIL

    (partial-freqs 300 300)

    => T

    (partial-freqs 300 300 nil)

    => NIL

SYNOPSIS

    (defun partial-freqs (freq1 freq2 &optional (unison-also t))

## utilities/power-of-2 [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Test whether the specified number is a power of two and return the
     logarithm of the specified number to base 2.

     This method returns two values: T or NIL for the test and a decimal that is
     the logarithm of the specified number to base 2.

ARGUMENTS

     - A number.

RETURN VALUE

     Two values: T or NIL for the test and a decimal number that is the
     logarithm of the specified number to base 2.

EXAMPLE

    (power-of-2 16)

    => T, 4.0

    (power-of-2 17.3)

    => NIL, 4.1127

SYNOPSIS

    (defun power-of-2 (float)

## utilities/pts2cm [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Convert a specified number of points to a length in centimeters at a
     resolution of 72ppi.

ARGUMENTS

     - A number.

RETURN VALUE

     A number.

EXAMPLE

    (pts2cm 150)

    => 5.2916665

SYNOPSIS

    (defun pts2cm (points)

## utilities/random-amount [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return a random number from within a total range of <percent> of the given
     number, centering around zero. Thus, if the <number> is 100, and the
     <percent> is 5, the results will be a random number between -2.5 and +2.5.

ARGUMENTS

     A number.

OPTIONAL ARGUMENTS

     A number that will be a percent of the given number.

RETURN VALUE

     A random positive or negative number.

EXAMPLE

    ;;; Using the default will return numbers within a 5% span of the given number,
    ;;; centering around zero. With 100 that means between -2.5 and +2.5.
    (loop repeat 10 collect (random-amount 100))

    => (0.7424975 -1.4954442 -1.7126495 1.5918689 -0.43478793 -1.7916341 -1.9115914
        0.8541988 0.057197176 2.0713913)

    ;;; Specifying 10% of 80 will return random numbers between -4.0 and +4.0
    (loop repeat 10 collect (random-amount 80 10))

    => (-0.66686153 3.0387697 3.4737322 -2.3753185 -0.8495751 -0.47580242
        -0.25743783 -1.1395472 1.3560238 -0.5958566)

SYNOPSIS

    (defun random-amount (number &optional (percent 5))

## utilities/random-from-list [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return a random element from a specified list of elements.

ARGUMENTS

     - A list.

OPTIONAL ARGUMENTS

     - An integer can be passed stating the length of the list, for more
       efficient processing. NB: There is no check to ensure this number is
       indeed the length of the list. If the number is less than the length of
       the list, only elements from the first part of the list will be
       returned. If it is greater than the length of the list, the method may
       return NIL.

RETURN VALUE

     An element from the specified list.

EXAMPLE

    (random-from-list '(3 5 7 11 13 17 19 23 29))

    => 13

SYNOPSIS

    (defun random-from-list (list &optional list-length) ; for efficiency

## utilities/randomise [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return a random decimal number close to the number specified (within a
     certain percentage of that number's value).

ARGUMENTS

     - A number.

OPTIONAL ARGUMENTS

     - A number that is a percentage value, such that any random number returned
       will be within that percentage of the original number's value.
       Default = 5.

RETURN VALUE

     A decimal number.

EXAMPLE

    (loop repeat 10 collect (randomise 100))

    => (99.413795 99.15346 98.682014 100.76199 97.74929 99.05693 100.59494 97.96452
        100.42091 100.01329)

SYNOPSIS

    (defun randomise (number &optional (percent 5))

## utilities/read-from-file [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Read a Lisp expression from a file. This is determined by the Lisp
     parenthetical syntax.

ARGUMENTS

     - A string that is a file name including directory path and extension.

RETURN VALUE

     The Lisp expression contained in the file.

EXAMPLE

    (read-from-file "/path/to/lisp-lorem-ipsum.txt")

    => (LOREM IPSUM DOLOR SIT AMET CONSECTETUR ADIPISCING ELIT CRAS CONSEQUAT
        CONVALLIS JUSTO VITAE CONSECTETUR MAURIS IN NIBH VEL EST TEMPUS LOBORTIS
        SUSPENDISSE POTENTI SED MAURIS MASSA ADIPISCING VITAE DIGNISSIM CONDIMENTUM
        VOLUTPAT VEL FELIS FUSCE AUGUE DUI PULVINAR ULTRICIES IMPERDIET SED
        PHARETRA EU QUAM INTEGER IN VULPUTATE VELIT ALIQUAM ERAT VOLUTPAT VIVAMUS
        SIT AMET ORCI EGET EROS CONSEQUAT TINCIDUNT NUNC ELEMENTUM ADIPISCING
        LOBORTIS MORBI AT LOREM EST EGET MATTIS ERAT DONEC AC RISUS A DUI MALESUADA
        LOBORTIS AC AT EST INTEGER AT INTERDUM TORTOR VIVAMUS HENDRERIT CONSEQUAT
        AUGUE QUISQUE ALIQUAM TELLUS NEC VESTIBULUM LOBORTIS RISUS TURPIS LUCTUS
        LIGULA IN BIBENDUM FELIS SEM PULVINAR DOLOR VIVAMUS RHONCUS NISI GRAVIDA
        PORTA VULPUTATE IPSUM LACUS PORTA RISUS A VULPUTATE MAGNA JUSTO A EST)

SYNOPSIS

    (defun read-from-file (file)

## utilities/reflect-list [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Order a list of numbers from least to greatest, then transpose the list so
     that if an element is the second lowest, it will be replaced by the second
     highest etc.

ARGUMENTS

     - A list or numbers.

RETURN VALUE

     A list of numbers.

EXAMPLE

    (reflect-list '(1 4 3 5 9 6 2 7 8 8 9))

    => (9 6 7 5 1 4 8 3 2 2 1)

SYNOPSIS

    (defun reflect-list (list)

## utilities/remove-all [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Remove all of the specified elements from a list, returning a list
     containing only those elements that are not in the first argument list.

ARGUMENTS

     - A first list that is the list of items to remove.
     - A second list that is the original list.

OPTIONAL ARGUMENTS

     - A predicate for testing equality between the elements of the two lists.
       Default = #'eq.

RETURN VALUE

     A list.

EXAMPLE

    (remove-all '(3 5 8 13) '(1 2 3 4 5 6 7 8 9 10 11 12 13))

    => (1 2 4 6 7 9 10 11 12)

SYNOPSIS

    (defun remove-all (rm-list list &optional (test #' eq))

## utilities/remove-elements [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Remove a specified number of elements from a given list starting at a
     specified position (0-based) within the list.

ARGUMENTS

     - A list.
     - An integer that is the 0-based position within that list that will be the
       first element to be removed.
     - An integer that is the number of elements to remove.

RETURN VALUE

     A list.

EXAMPLE

    (remove-elements '(1 2 3 4 5 6 7) 2 4)

    => (1 2 7)

SYNOPSIS

    (defun remove-elements (list start how-many)

## utilities/remove-more [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Remove all instances of a list of specified elements from an original
     list. The predicate used to test the presence of the specified elements in
     the original list must be specified by the user (such as #'eq, #'equalp,
     #'= etc.)

ARGUMENTS

     - A list.
     - A predicate with which to test the presence of the specified elements.
     - A sequence of elements to be removed from the given list.

RETURN VALUE

     A list.

EXAMPLE

    (remove-more '(1 2 3 4 5 5 5 6 7 7 8) #'= 5 7 2)

    => (1 3 4 6 8)

SYNOPSIS

    (defun remove-more (list test &rest remove)

## utilities/repeat-env [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Create a new list by repeating the y values of a list of break-point pairs
     a specified number of times over the same total x-axis span of the original
     envelope. A quick ramp is inserted between repeats to ensure that all
     x-axis values are unique and incremental.

     If the optional argument is set to T, the method will reverse the order of
     every second repeat.

ARGUMENTS

     - An envelope in the form of a list of break-point pairs.
     - An integer that is the number of times the elements of the given envelope
       should be repeated in the new list.

OPTIONAL ARGUMENTS

     - T or NIL to indicate whether every second repetition of the original
       envelope should be returned in reverse order.
       T = reverse. Default = NIL.

RETURN VALUE

     - A new envelope in the form of a list of break-point pairs.

EXAMPLE

    (repeat-env '(0 1 50 2 100 3) 3)

    => (0.0 1 16.666666 2 33.333332 3 34.333332 1 50.0 2 66.666664 3 67.666664 1
        83.33333 2 100.0 3)

    (repeat-env '(0 1 50 2 100 3) 3 t)

    => (0.0 1 16.666666 2 33.333332 3 50.0 2 66.666664 1 83.33333 2 100.0 3)

SYNOPSIS

    (defun repeat-env (env num-times &optional reflected)

## utilities/replace-elements [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Replace the elements in list between start and end (inclusive) with the new
     list.

ARGUMENTS

     - A list.
     - An integer that is first position of the segment of the original list to
       be replaced.
     - An integer that is the last position of the segment of the original list
       to be replaced.
     - A list that is to replace the specified segment of the original
       list. This list can be of a different length than that of the segment
       of the original specified by the start and end positions.

RETURN VALUE

     A list.

EXAMPLE

    (replace-elements '(1 2 3 4 5 6 7 8 9) 3 7 '(dog cat goldfish))

    => (1 2 3 DOG CAT GOLDFISH 9)

SYNOPSIS

    (defun replace-elements (list start end new)

## utilities/reverse-env [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Reverse the order of y values in a list of break-point pairs.

ARGUMENTS

     - An envelope in the form of a list of break-point pairs.

RETURN VALUE

     An envelope in the form of a list of break-point pairs.

EXAMPLE

    (reverse-env '(0 0 25 11 50 13 75 19 100 23))

    => (0 23 25 19 50 13 75 11 100 0)

SYNOPSIS

    (defun reverse-env (env)

## utilities/round-if-close [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Round a decimal number if it is within a given tolerance to the next whole
     number.

ARGUMENTS

     - A decimal number.

OPTIONAL ARGUMENTS

     - If the given number is this amount or less than the nearest whole number,
       round the given number to the nearest whole number.

RETURN VALUE

     If the given number is within the tolerance, return the number, otherwise
     return the nearest whole number.

EXAMPLE

    (round-if-close 1.999998)

    => 1.999998

    (round-if-close 1.999999)

    => 2

SYNOPSIS

    (defun round-if-close (num &optional (tolerance 0.000001))

## utilities/scale-env [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Scale either the x-axis values, the data values, or both of a list of
     break-point pairs by specified factors.

ARGUMENTS

     - An envelope in the form of a list of break-point pairs.
     - A number that is the factor by which the y values (data segment of the
       break-point pairs) are to be scaled.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :y-min. A number that is the minimum value for all y values after
       scaling.
     - :y-max. A number that is the maximum value for all y values after
       scaling.
     - :x-scaler. A number that is the factor by which to scale the x-axis
       values of the break-point pairs.
     - :x-min. A number that is the minimum value for all x values after
       scaling. NB: This optional argument can only be used if a value has been
       specified for the :x-scaler.
     - :x-max. A number that is the maximum value for all x values after
       scaling. NB: This optional argument can only be used if a value has been
       specified for the :x-scaler.

RETURN VALUE

     An envelope in the form of a list of break-point pairs.

EXAMPLE

    ;;; Scaling only the y values.
    (scale-env '(0 53 25 189 50 7 75 200 100 3) 0.5)

    => (0 26.5 25 94.5 50 3.5 75 100.0 100 1.5)

    ;;; Scaling the y values and setting a min and max for those values
    (scale-env '(0 53 25 189 50 7 75 200 100 3) 0.5 :y-min 20 :y-max 100)

    => (0 26.5 25 94.5 50 20 75 100 100 20)

    ;;; Scaling only the x-axis values
    (scale-env '(0 53 25 189 50 7 75 200 100 3) 1.0 :x-scaler 2)

    => (0 53.0 50 189.0 100 7.0 150 200.0 200 3.0)

    ;;; Scaling the x values and setting a min and max for those values
    (scale-env '(0 53 25 189 50 7 75 200 100 3) 1.0 :x-scaler 2 :x-min 9 :x-max 90)

    => (9 53.0 50 189.0 90 7.0 90 200.0 90 3.0)

SYNOPSIS

    (defun scale-env (env y-scaler &key x-scaler
                                        (x-min most-negative-double-float)
                                        (y-min most-negative-double-float)
                                        (x-max most-positive-double-float)
                                        (y-max most-positive-double-float))

## utilities/secs-to-mins-secs [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

ARGUMENTS

OPTIONAL ARGUMENTS

RETURN VALUE

EXAMPLE

SYNOPSIS

    (defun secs-to-mins-secs (seconds &key
                              (mins-separator ":")
                              (secs-separator ".")
                              (msecs-separator "")
                              (same-width nil))

## utilities/semitones [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return the sample-rate conversion factor required for transposing an audio
     file by a specific number of semitones. The number of semitones can be
     given as a decimal number, and may be positive or negative.

ARGUMENTS

     - A number of semitones.

OPTIONAL ARGUMENTS

     - A number that is the factor required to transpose by an octave.
       Default = 2.0.
     - A number that is the number of semitones per octave. Default = 12.

RETURN VALUE

     A number.

EXAMPLE

    ;;; Usage with default values
    (semitones 3)

    => 1.1892071

    ;;; Specifying a different number of semitones per octave
    (semitones 3 2.0 13)

    => 1.1734605

    ;;; Specifying a different factor for transposing by an octave
    (semitones 3 4.0)

    => 1.4142135

    ;;; Fractional semitones are allowed
    (semitones 3.72)

    => 1.2397077

    ;;; Negative semitones are also allowed
    (semitones -3.72)

    => 0.80664176

SYNOPSIS

    (defun semitones (st &optional (octave-size 2.0) (divisions-per-octave 12))

## utilities/setf-last [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Change the last element in a given list to a specified new element.

ARGUMENTS

     - A list.
     - The new last element of that list.

RETURN VALUE

     Returns the new last element.

EXAMPLE

    (let ((l '(1 2 3 4 5)))
      (setf-last l 'dog)
      l)

    => (1 2 3 4 DOG)

SYNOPSIS

    (defmacro setf-last (list new-last)

## utilities/sort-symbol-list [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Sort a list of symbols alphabetically ascending, case-insensitive.

ARGUMENTS

     A list of symbols.

RETURN VALUE

     The same list of symbols sorted alphabetically ascending, case-insensitive.

EXAMPLE

    (sort-symbol-list '(Lorem ipsum dolor sit amet consectetur adipiscing))

    => (ADIPISCING AMET CONSECTETUR DOLOR IPSUM LOREM SIT)

SYNOPSIS

    (defun sort-symbol-list (list)

## utilities/splice [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Insert the elements of a first list into a second list beginning at a
     specified index (0-based).

ARGUMENTS

     - A list that contains the elements to be inserted into the second list.
     - A list into which the elements of the first argument are to be inserted.
     - An integer that is the index within the second list where the elements
       are to be inserted.

RETURN VALUE

     - A list.

EXAMPLE

    (splice '(dog cat goldfish) '(1 2 3 4 5 6 7 8 9) 3)

    => (1 2 3 DOG CAT GOLDFISH 4 5 6 7 8 9)

SYNOPSIS

    (defun splice (elements into-list where)

## utilities/split-groups [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Create a list consisting of as many repetitions of a specified number as
     will fit into a given greater number, with the last item in the new list
     being the value of any remainder.

ARGUMENTS

     - A number that is to be split into repetitions of a specified smaller
       number (the second argument).
     - The number that is to be the repeating item in the new list. This number
       must be smaller than the first number.

RETURN VALUE

     A list consisting of repetitions of the specified number, with the last
     element being any possible remainder.

EXAMPLE

    (split-groups 101 17)

    => (17 17 17 17 17 16)

SYNOPSIS

    (defun split-groups (num divider)

## utilities/split-into-sub-groups [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Create a new list consisting of sublists made from the elements of the
     original flat list, whose lengths are determined by the second argument to
     the function.

     NB: The lengths given in the second argument are not required to add up to
         the length of the original list. If their sum is less than the original
         list, the resulting list of sublists will only contain a segment of the
         original elements. If their sum is greater than the length of the
         original list, the last sublist in the new list will be shorter than
         the corresponding group value.

ARGUMENTS

     - A flat list.
     - A list of integers that are the lengths of the consecutive subgroups
       into which the original list is to be divided.

RETURN VALUE

     A list of lists.

EXAMPLE

    ;; Used with a list of subgroup lengths whose sum is equal to the length of the
    ;; original list
    (split-into-sub-groups '(1 2 3 4 5 6 7 8 9 10) '(2 2 3 2 1))

    => ((1 2) (3 4) (5 6 7) (8 9) (10))

    ;; Used with a list of subgroup lengths whose sum is less than the length of the
    ;; original list
    (split-into-sub-groups '(1 2 3 4 5 6 7 8 9 10) '(2 1))

    => ((1 2) (3))

    ;; Used with a list of subgroup lengths whose sum is greater than the length of
    ;; the original list
    (split-into-sub-groups '(1 2 3 4 5 6 7 8 9 10) '(2 3 17))

    => ((1 2) (3 4 5) (6 7 8 9 10))

SYNOPSIS

    (defun split-into-sub-groups (list groups)

## utilities/split-into-sub-groups2 [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Create a new list of lists by splitting the original flat list into
     sublists of the specified length.

     NB: The length given as the second argument is not required to be fit
         evenly into the length of the original flat list. If the original list
         is not evenly divisible by the specified length, the resulting list of
         sublists will contain a final sublist of a different length.

ARGUMENTS

     - A flat list.
     - An integer that is the length of each of the sublists to be created.

RETURN VALUE

     A list of lists.

EXAMPLE

    ;; The second argument fits evenly into the length of the original list.
    (split-into-sub-groups2 '(1 2 3 4 5 6 7 8 9 10 11 12) 3)

    => ((1 2 3) (4 5 6) (7 8 9) (10 11 12))

    ;; The second argument does not fit evenly into the length of the original
    ;; list.

    (split-into-sub-groups2 '(1 2 3 4 5 6 7 8 9 10 11 12) 5)

    => ((1 2 3 4 5) (6 7 8 9 10) (11 12))

SYNOPSIS

    (defun split-into-sub-groups2 (list length)

## utilities/split-into-sub-groups3 [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Split a given flat list into sublists of the specified length, putting any
     remaining elements, if there are any, into the last sublist.

ARGUMENTS

     - A flat list.
     - An integer that is the length of the new sublists.

RETURN VALUE

     A list of lists.

EXAMPLE

    (split-into-sub-groups3 '(1 2 3 4 5 6 7 8 9 10 11 12) 3)

    => ((1 2 3) (4 5 6) (7 8 9) (10 11 12))

    (split-into-sub-groups3 '(1 2 3 4 5 6 7 8 9 10 11 12) 5)

    => ((1 2 3 4 5) (6 7 8 9 10 11 12))

SYNOPSIS

    (defun split-into-sub-groups3 (list length)

## utilities/srt [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Return the semitone transposition for a given sampling rate conversion
     factor.

ARGUMENTS

     - A number that is a sample-rate conversion factor.

OPTIONAL ARGUMENTS

     - A number that is the factor required for transposing one octave.
     - A number that is the number of scale degrees in an octave.

RETURN VALUE

     A number.

EXAMPLE

    ;;; Using the defaults
    (srt 1.73)

    => 9.4893

    ;;; Using a sample-rate conversion factor of 4.0 for the octave and specifying
    ;;; 13 divisions of the octave
    (srt 1.73 4.0 13)

    => 5.14

SYNOPSIS

    (let ((last8vesize 0)
          (log8ve 0.0)) ;; so we don't have to recalculate each time
      (defun srt (srt &optional (octave-size 2.0) (divisions-per-octave 12)
                  ;; MDE Tue Feb  7 16:59:45 2012 -- round so we don't get tiny
                  ;; fractions of semitones due to float inaccuracies?
                  (round-to 0.0001))

## utilities/string-replace [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Replace specified segments of a string with a new specified string.

ARGUMENTS

     - A string that is the string segment to be replaced.
     - A string that is the string with which the specified string segment is to
       be replaced.
     - The string in which the specified segment is to be sought and replaced.

RETURN VALUE

     A string.

EXAMPLE

    (string-replace "flat" "\\flat" "bflat clarinet")

    => "b\\flat clarinet"

SYNOPSIS

    (defun string-replace (what with string)

## utilities/swap-elements [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Swap the order of each consecutive pair of elements in a list.

ARGUMENTS

     - A list.

RETURN VALUE

     A list.

EXAMPLE

    (swap-elements '(1 2 3 4 5 6 7 8 9 10))

    => (2 1 4 3 6 5 8 7 10 9)

    (swap-elements '(1 2 3 4 5 6 7 8 9))

    => (2 1 4 3 6 5 8 7 9)

SYNOPSIS

    (defun swap-elements (list)

## utilities/update-app-src [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DATE

     June 1st 2013

DESCRIPTION

     NB This function currently works in SBCL and CCL on UNIX systems only.

     For users of the slippery chicken app, this function will update the source
     code of the app to the latest in the online subversion (svn) repository.
     An internet connection is therefore necessary.

     The first time it is run it will delete the current source code and
     download all the new source code, so make sure to back up if you've
     modified the source code yourself.  When it is run from then on, it will
     only update the source code that is out of date.

     Once the source code is updated, you'll need to restart the app or just
     Lisp for the changes to be recompiled.

     Users without the app can always download the latest source code in a
     terminal by issuing the following command.
     svn co https://svn.ecdf.ed.ac.uk/repo/user/medward2/sc-tags/sc-latest/src

     The first time you call this function, you might get a certificate error.
     In order to accept the certificate, start the terminal application and type
     the following:

     cd /tmp/
     svn co https://svn.ecdf.ed.ac.uk/repo/user/medward2/sc-tags/sc-latest/src

     That should give you a prompt in the terminal from which you can accept the
     certificate.  Then the next time you try it from Lisp the certificate
     should not cause a problem.

ARGUMENTS

     The full path to the slippery-chicken application, minus the last slash.
     Remember that this can't include any spaces in file/folder names

OPTIONAL ARGUMENTS

     keyword arguments:
     :rm.  The path to the shell 'rm' command.  Default = "/bin/rm"
     :svn.  The path to the shell 'svn' command.  Default = "/usr/bin/svn"

RETURN VALUE

     The shell return value of the call to SVN, usually 0 on success.

EXAMPLE

    Running for the first time:
    (update-app-src "/tmp/sc-app/slippery-chicken.app")
    A    /tmp/sc-app/slippery-chicken.app/Contents/Resources/sc/src/sndfile.lsp
    A    /tmp/sc-app/slippery-chicken.app/Contents/Resources/sc/src/osc.lsp
    A    /tmp/sc-app/slippery-chicken.app/Contents/Resources/sc/src/osc-sc.lsp
    [...]
    Checked out revision 3608.
    0

    or after successfully updating a previously updated version:
    ...
    At revision 3608.
    0

SYNOPSIS

    (defun update-app-src (path-to-app &key (rm "/bin/rm") (svn "/usr/bin/svn"))

## utilities/wavelab-to-audacity-marker-file [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Write a .txt file suitable for import to audacity with the same name and in
     the same directory as the file argument.

ARGUMENTS

     - A string that is the name of a wavelab marker file, including directory
       path and extension.

OPTIONAL ARGUMENTS

     - An integer that is the sampling rate of the sound file to which the
       wavelab marker file refers. This value will affect the times of the
       output.

RETURN VALUE

     Returns T and prints the number of markers read to the listener.

EXAMPLE

    (wavelab-to-audacity-marker-file "/path/to/24-7.mrk"  44100)

    => 51 markers read

SYNOPSIS

    (defun wavelab-to-audacity-marker-file (file &optional (sampling-rate 44100))

## utilities/wrap-list [ Functions ]

[ Top ] [ utilities ] [ Functions ]

DESCRIPTION

     Shift the elements of a list to start at a specified position and wrap to
     the beginning of the list to the list's tail.

ARGUMENTS

     - A list.
     - An integer which is the 0-based position in the original list where the
       new list is to begin.

RETURN VALUE

     A list.

EXAMPLE

    (wrap-list '(1 2 3 4 5 6 7 8 9) 4)

    => (5 6 7 8 9 1 2 3 4)

SYNOPSIS

    (defun wrap-list (list start)