From eb7cb685924141e5e166000e7424d5e2d9933b82 Mon Sep 17 00:00:00 2001
From: Peter Luenenschloss <peter.luenenschloss@ufz.de>
Date: Fri, 6 Dec 2019 14:32:37 +0100
Subject: [PATCH] Update FunctionDescriptions.md
---
docs/FunctionDescriptions.md | 41 ++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/docs/FunctionDescriptions.md b/docs/FunctionDescriptions.md
index e3d2d1256..0c050cfda 100644
--- a/docs/FunctionDescriptions.md
+++ b/docs/FunctionDescriptions.md
@@ -15,6 +15,47 @@ range(min, max)
### Description
+## `isolated`
+
+### Signature
+```
+isolated(isolation_range, max_isolated_group_size=1, continuation_range='1min',
+ drop_flags=None)
+```
+### Parameters
+| parameter | data type | default value | description |
+| --------- | --------- | ------------- | ----------- |
+| isolation_range | string | | Offset string. The range, within there are no valid values allowed for a valuegroup to get flagged isolated. See condition (1) and (2).|
+| max_isolated_group_size | integer | `1` | The upper bound for the size of a value group to be considered an isolated group. See condition (3).|
+| continuation_range | string | `"1min"` | Offset string. The upper bound for the temporal extension of a value group to be considered an isolated group. See condition (4). Only relevant if `max_islated_group_size` > 1.|
+| drop_flags | list or Nonetype| `None` | A list of flags, that are to be considered, signifying invalid values. See condition (1) and (2).|
+
+### Description
+
+The function flags isolated values / value groups.
+Isolated values are values / value groups,
+that, in a range of `isolation_range`,
+are surrounded either by invalid values only, or by no values.
+
+The function defaults to flag isolated single values only. But the parameters
+allow for detections of more complex isolation definitions, including groups
+of isolated values.
+
+A continuous group of values
+$`x_{k}, x_{k+1},...,x_{k+n}`$ of the timeseries of meassurements $`x`$,
+is considered "isolated", if:
+
+1. There are no values, preceeding $`x_{k}`$ within `isolation_range` or all the
+ preceeding values within this range are flagged with a flag listed in
+ `drop_list`.
+2. There are no values, succeeding $`x_{k+n}`$, within `isolation_range`, or all the
+ succeeding values within this range are flagged with a flag listed in
+ `drop_list`.
+3. $`n \leq `$ `max_isolated_group_size`
+4. $` |y_{k} - y_{n+k}| < `$ `continuation_range`, with $`y `$, denoting the series
+ of timestamps associated with $`x`$.
+
+
## `missing`
--
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