Skip to content

fix broken quartiles method in isoutlier #482

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
pr0m1th3as merged 4 commits into from
Sep 16, 2026
Merged

fix broken quartiles method in isoutlier #482

Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
85f0ae0
correct dim argument and center formula in quartiles method
AvanishSalunke Sep 12, 2026
f386114
changes in the docstring
AvanishSalunke Sep 12, 2026
888b028
add comment on the BISTs
AvanishSalunke Sep 12, 2026
89f46b7
document C formula for quartiles method
AvanishSalunke Sep 12, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
55 changes: 47 additions & 8 deletions inst/Data_Manipulation/isoutlier.m
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -124,8 +124,7 @@
## from 0 to 1, specifying the critical @math{alpha}-value of the respective
## test, and it is 0.05 by default. For the @qcode{'quartiles'} method, the
## detection threshold factor replaces the number of interquartile ranges, which
## is 1.5 by default. @qcode{'ThresholdFactor'} is not supported for the
## @qcode{'quartiles'} method.
## is 1.5 by default.
##
## @item @qcode{'MaxNumOutliers'} is only relevant to the @qcode{'gesd'} method
## and it must be a positive integer scalar specifying the maximum number of
Expand Down Expand Up @@ -163,8 +162,9 @@
## @qcode{'movmean'} methods, @var{C} is computed by taking into account the
## outlier values. For @qcode{'grubbs'} and @qcode{'gesd'} methods, @var{C} is
## computed by excluding the outliers. For the @qcode{'percentiles'} method,
## @var{C} is the average between @var{U} and @var{L} thresholds.
## @end itemize
## @var{C} is the average between @var{U} and @var{L} thresholds. For the
## @qcode{'quartiles'} method, @var{C} is the average of the 25th and 75th
## percentiles.
##
## @seealso{filloutliers, rmoutliers, ismissing}
## @end deftypefn
Expand Down Expand Up @@ -378,10 +378,11 @@

## Find lower and upper outlier thresholds with quartiles method
function [L, U, C] = quartiles_method (x, dim, ThresholdFactor)
Q = quantile (x, dim);
C = Q(3);
L = Q(2) - (Q(4) - Q(2)) * ThresholdFactor;
U = Q(4) + (Q(4) - Q(2)) * ThresholdFactor;
Q1 = quantile (x, 0.25, dim);
Q3 = quantile (x, 0.75, dim);
C = (Q1 + Q3) / 2;
L = Q1 - (Q3 - Q1) * ThresholdFactor;
U = Q3 + (Q3 - Q1) * ThresholdFactor;
endfunction

## Find lower and upper outlier thresholds with grubbs method
Expand Down Expand Up @@ -813,6 +814,44 @@
%! assert_equal (U, 62)
%! assert_equal (C, 59.75)

## Quartiles method: base case, ThresholdFactor override, dim = 1 and
## dim = 2 on a matrix, and NaN omission
%!test
%! A = [57 59 60 100 59 58 57 58 300 61 62 60 62 58 57];
%! [TF, L, U, C] = isoutlier (A, 'quartiles');
%! assert_equal (TF, logical ([0 0 0 1 0 0 0 0 1 0 0 0 0 0 0]))
%! assert_equal (L, 52.375, 1e-12)
%! assert_equal (U, 67.375, 1e-12)
%! assert_equal (C, 59.875, 1e-12)
%!test
%! A = [57 59 60 100 59 58 57 58 300 61 62 60 62 58 57];
%! [TF, L, U, C] = isoutlier (A, 'quartiles', 'ThresholdFactor', 1);
%! assert_equal (TF, logical ([0 0 0 1 0 0 0 0 1 0 0 0 0 0 0]))
%! assert_equal (L, 54.25, 1e-12)
%! assert_equal (U, 65.5, 1e-12)
%! assert_equal (C, 59.875, 1e-12)
%!test
%! B = magic (5) + diag (200 * ones (1, 5));
%! [TF, L, U, C] = isoutlier (B, 'quartiles', 1);
%! assert_equal (TF, logical (eye (5)))
%! assert_equal (L, [-86, -77.625, -94.25, -89.125, -73.125], 1e-12)
%! assert_equal (U, [166, 157.375, 171.75, 165.875, 153.875], 1e-12)
%! assert_equal (C, [40, 39.875, 38.75, 38.375, 40.375], 1e-12)
%!test
%! B = magic (5) + diag (200 * ones (1, 5));
%! [TF, L, U, C] = isoutlier (B, 'quartiles', 2);
%! assert_equal (TF, logical (eye (5)))
%! assert_equal (L, [-92.75; -72.125; -90.875; -83.625; -84.625], 1e-12)
%! assert_equal (U, [171.25; 152.875; 166.125;161.375; 164.375], 1e-12)
%! assert_equal (C, [39.25; 40.375; 37.625; 38.875; 39.875], 1e-12)
%!test
%! A = [57 59 60 100 59 NaN 57 58 300 61 62 60 62 58 57];
%! [TF, L, U, C] = isoutlier (A, 'quartiles');
%! assert_equal (TF, logical ([0 0 0 1 0 0 0 0 1 0 0 0 0 0 0]))
%! assert_equal (L, 52, 1e-12)
%! assert_equal (U, 68, 1e-12)
%! assert_equal (C, 60, 1e-12)

## Test input validation
%!shared A
%! A = [57 59 60 100 59 58 57 58 300 61 62 60 62 58 57];
Expand Down