drasi_core/evaluation/functions/drasi/
stdevp.rs

1// Copyright 2024 The Drasi Authors.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use crate::evaluation::functions::ScalarFunction;
16use crate::evaluation::{FunctionError, FunctionEvaluationError};
17use async_trait::async_trait;
18use drasi_query_ast::ast;
19use statistical::{mean, population_standard_deviation};
20
21use crate::evaluation::{variable_value::VariableValue, ExpressionEvaluationContext};
22
23#[derive(Clone)]
24pub struct DrasiStdevP {}
25
26//NOTE: Do we want this to be an aggregating function instead?
27#[async_trait]
28impl ScalarFunction for DrasiStdevP {
29    async fn call(
30        &self,
31        _context: &ExpressionEvaluationContext,
32        expression: &ast::FunctionExpression,
33        args: Vec<VariableValue>,
34    ) -> Result<VariableValue, FunctionError> {
35        if args.len() != 1 {
36            return Err(FunctionError {
37                function_name: expression.name.to_string(),
38                error: FunctionEvaluationError::InvalidArgumentCount,
39            });
40        }
41        match &args[0] {
42            VariableValue::Null => Ok(VariableValue::Null),
43            VariableValue::List(l) => {
44                let mut cleaned_list = vec![];
45                for element in l {
46                    match element {
47                        VariableValue::Integer(i) => {
48                            cleaned_list.push(match i.as_i64() {
49                                Some(i) => i as f64,
50                                None => {
51                                    return Err(FunctionError {
52                                        function_name: expression.name.to_string(),
53                                        error: FunctionEvaluationError::OverflowError,
54                                    })
55                                }
56                            });
57                        }
58                        VariableValue::Float(f) => {
59                            cleaned_list.push(match f.as_f64() {
60                                Some(f) => f,
61                                None => {
62                                    return Err(FunctionError {
63                                        function_name: expression.name.to_string(),
64                                        error: FunctionEvaluationError::OverflowError,
65                                    })
66                                }
67                            });
68                        }
69                        VariableValue::Null => {
70                            continue;
71                        }
72                        _ => {
73                            continue;
74                        }
75                    }
76                }
77                let mean = mean(&cleaned_list);
78                let stdevp = population_standard_deviation(&cleaned_list, Some(mean));
79
80                Ok(VariableValue::Float(stdevp.into()))
81            }
82            _ => Err(FunctionError {
83                function_name: expression.name.to_string(),
84                error: FunctionEvaluationError::InvalidArgument(0),
85            }),
86        }
87    }
88}
drasi_core/evaluation/functions/drasi/stdevp.rs

drasi_core/evaluation/functions/drasi/
stdevp.rs
