nu_command/matrix/
max.rs

1use crate::matrix::MatrixValue;
2use ndarray::Axis;
3use nu_engine::command_prelude::*;
4
5#[derive(Clone)]
6pub struct MatrixMax;
7
8impl Command for MatrixMax {
9    fn name(&self) -> &str {
10        "matrix max"
11    }
12
13    fn signature(&self) -> Signature {
14        Signature::build("matrix max")
15            .input_output_types(vec![
16                (Type::Custom("matrix".into()), Type::Float),
17                (Type::Custom("matrix".into()), Type::Custom("matrix".into())),
18            ])
19            .named(
20                "axis",
21                SyntaxShape::Int,
22                "The axis to find the max along (0-based).",
23                Some('a'),
24            )
25            .category(Category::Filters)
26    }
27
28    fn description(&self) -> &str {
29        "Find the maximum value in a matrix, or max along an axis."
30    }
31
32    fn search_terms(&self) -> Vec<&str> {
33        vec!["maximum"]
34    }
35
36    fn run(
37        &self,
38        engine_state: &EngineState,
39        stack: &mut Stack,
40        call: &Call,
41        input: PipelineData,
42    ) -> Result<PipelineData, ShellError> {
43        let head = call.head;
44        let axis: Option<i64> = call.get_flag(engine_state, stack, "axis")?;
45        let matrix = MatrixValue::from_value(&input.into_value(head)?)?;
46
47        match axis {
48            Some(axis) => {
49                let axis = axis as usize;
50                if axis >= matrix.array.ndim() {
51                    return Err(ShellError::Generic(
52                        nu_protocol::shell_error::generic::GenericError::new(
53                            "Invalid axis",
54                            format!(
55                                "axis {} is out of bounds for a {}-dimensional array",
56                                axis,
57                                matrix.array.ndim()
58                            ),
59                            head,
60                        ),
61                    ));
62                }
63                let result = matrix.array.map_axis(Axis(axis), |view| {
64                    view.iter().cloned().fold(f64::NEG_INFINITY, f64::max)
65                });
66                Ok(MatrixValue::new(result)
67                    .into_value(head)
68                    .into_pipeline_data())
69            }
70            None => {
71                let max_val: f64 = matrix
72                    .array
73                    .iter()
74                    .cloned()
75                    .fold(f64::NEG_INFINITY, f64::max);
76                Ok(Value::float(max_val, head).into_pipeline_data())
77            }
78        }
79    }
80
81    fn examples(&self) -> Vec<Example<'static>> {
82        vec![
83            Example {
84                description: "Find the maximum element in a matrix",
85                example: "[[1 2] [3 4]] | into matrix | matrix max",
86                result: Some(Value::test_float(4.0)),
87            },
88            Example {
89                description: "Find max along rows (axis 0)",
90                example: "[[1 2] [3 4]] | into matrix | matrix max --axis 0 | matrix into-nu | to nuon",
91                result: Some(Value::test_string("[[3.0, 4.0]]")),
92            },
93            Example {
94                description: "Find max along columns (axis 1)",
95                example: "[[1 2] [3 4]] | into matrix | matrix max --axis 1 | matrix into-nu | to nuon",
96                result: Some(Value::test_string("[[2.0, 4.0]]")),
97            },
98        ]
99    }
100}
101
102#[cfg(test)]
103mod test {
104    use super::*;
105
106    #[test]
107    fn test_examples() -> nu_test_support::Result {
108        nu_test_support::test().examples(MatrixMax)
109    }
110}
nu_command/matrix/max.rs

nu_command/matrix/
max.rs
