feat: Add vector_scalar_mul function.

src/common/function/src/scalars/vector.rs

@@ -16,6 +16,7 @@ mod convert;
 mod distance;
 pub(crate) mod impl_conv;
 mod scalar_add;
+mod scalar_mul;
 
 use std::sync::Arc;
 
@@ -36,5 +37,6 @@ impl VectorFunction {
 
         // scalar calculation
         registry.register(Arc::new(scalar_add::ScalarAddFunction));
+        registry.register(Arc::new(scalar_mul::ScalarMulFunction));
     }
 }

src/common/function/src/scalars/vector/scalar_mul.rs

@@ -0,0 +1,173 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::borrow::Cow;
+use std::fmt::Display;
+
+use common_query::error::{InvalidFuncArgsSnafu, Result};
+use common_query::prelude::Signature;
+use datatypes::prelude::ConcreteDataType;
+use datatypes::scalars::ScalarVectorBuilder;
+use datatypes::vectors::{BinaryVectorBuilder, MutableVector, VectorRef};
+use nalgebra::DVectorView;
+use snafu::ensure;
+
+use crate::function::{Function, FunctionContext};
+use crate::helper;
+use crate::scalars::vector::impl_conv::{as_veclit, as_veclit_if_const, veclit_to_binlit};
+
+const NAME: &str = "vec_scalar_mul";
+
+/// Multiples a scalar to each element of a vector.
+///
+/// # Example
+///
+/// ```sql
+/// SELECT vec_to_string(vec_scalar_mul(2, "[1, 2, 3]")) as result;
+///
+/// +---------+
+/// | result  |
+/// +---------+
+/// | [2,4,6] |
+/// +---------+
+///
+/// -- 1/scalar to simulate division
+/// SELECT vec_to_string(vec_scalar_mul(0.5, "[2, 4, 6]")) as result;
+///
+/// +---------+
+/// | result  |
+/// +---------+
+/// | [1,2,3] |
+/// +---------+
+/// ```
+#[derive(Debug, Clone, Default)]
+pub struct ScalarMulFunction;
+
+impl Function for ScalarMulFunction {
+    fn name(&self) -> &str {
+        NAME
+    }
+
+    fn return_type(&self, _input_types: &[ConcreteDataType]) -> Result<ConcreteDataType> {
+        Ok(ConcreteDataType::binary_datatype())
+    }
+
+    fn signature(&self) -> Signature {
+        helper::one_of_sigs2(
+            vec![ConcreteDataType::float64_datatype()],
+            vec![
+                ConcreteDataType::string_datatype(),
+                ConcreteDataType::binary_datatype(),
+            ],
+        )
+    }
+
+    fn eval(&self, _func_ctx: FunctionContext, columns: &[VectorRef]) -> Result<VectorRef> {
+        ensure!(
+            columns.len() == 2,
+            InvalidFuncArgsSnafu {
+                err_msg: format!(
+                    "The length of the args is not correct, expect exactly two, have: {}",
+                    columns.len()
+                ),
+            }
+        );
+        let arg0 = &columns[0];
+        let arg1 = &columns[1];
+
+        let len = arg0.len();
+        let mut result = BinaryVectorBuilder::with_capacity(len);
+        if len == 0 {
+            return Ok(result.to_vector());
+        }
+
+        let arg1_const = as_veclit_if_const(arg1)?;
+
+        for i in 0..len {
+            let arg0 = arg0.get(i).as_f64_lossy();
+            let Some(arg0) = arg0 else {
+                result.push_null();
+                continue;
+            };
+
+            let arg1 = match arg1_const.as_ref() {
+                Some(arg1) => Some(Cow::Borrowed(arg1.as_ref())),
+                None => as_veclit(arg1.get_ref(i))?,
+            };
+            let Some(arg1) = arg1 else {
+                result.push_null();
+                continue;
+            };
+
+            let vec = DVectorView::from_slice(&arg1, arg1.len());
+            let vec_res = vec.scale(arg0 as _);
+
+            let veclit = vec_res.as_slice();
+            let binlit = veclit_to_binlit(veclit);
+            result.push(Some(&binlit));
+        }
+
+        Ok(result.to_vector())
+    }
+}
+
+impl Display for ScalarMulFunction {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", NAME.to_ascii_uppercase())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+
+    use datatypes::vectors::{Float32Vector, StringVector};
+
+    use super::*;
+
+    #[test]
+    fn test_scalar_mul() {
+        let func = ScalarMulFunction;
+
+        let input0 = Arc::new(Float32Vector::from(vec![
+            Some(2.0),
+            Some(-0.5),
+            None,
+            Some(3.0),
+        ]));
+        let input1 = Arc::new(StringVector::from(vec![
+            Some("[1.0,2.0,3.0]".to_string()),
+            Some("[8.0,10.0,12.0]".to_string()),
+            Some("[7.0,8.0,9.0]".to_string()),
+            None,
+        ]));
+
+        let result = func
+            .eval(FunctionContext::default(), &[input0, input1])
+            .unwrap();
+
+        let result = result.as_ref();
+        assert_eq!(result.len(), 4);
+        assert_eq!(
+            result.get_ref(0).as_binary().unwrap(),
+            Some(veclit_to_binlit(&[2.0, 4.0, 6.0]).as_slice())
+        );
+        assert_eq!(
+            result.get_ref(1).as_binary().unwrap(),
+            Some(veclit_to_binlit(&[-4.0, -5.0, -6.0]).as_slice())
+        );
+        assert!(result.get_ref(2).is_null());
+        assert!(result.get_ref(3).is_null());
+    }
+}

tests/cases/standalone/common/function/vector/vector_scalar.result

@@ -46,3 +46,51 @@ SELECT vec_to_string(vec_scalar_add(-1, '[1.0, 2.0]'));
 | [0,1]                                                       |
 +-------------------------------------------------------------+
 
+SELECT vec_to_string(vec_scalar_mul(1.0, '[1.0, 2.0]'));
+
++--------------------------------------------------------------+
+| vec_to_string(vec_scalar_mul(Float64(1),Utf8("[1.0, 2.0]"))) |
++--------------------------------------------------------------+
+| [1,2]                                                        |
++--------------------------------------------------------------+
+
+SELECT vec_to_string(vec_scalar_mul(-0.5, '[2.0, 4.0]'));
+
++-----------------------------------------------------------------+
+| vec_to_string(vec_scalar_mul(Float64(-0.5),Utf8("[2.0, 4.0]"))) |
++-----------------------------------------------------------------+
+| [-1,-2]                                                         |
++-----------------------------------------------------------------+
+
+SELECT vec_to_string(vec_scalar_mul(1.0, parse_vec('[1.0, 2.0]')));
+
++-------------------------------------------------------------------------+
+| vec_to_string(vec_scalar_mul(Float64(1),parse_vec(Utf8("[1.0, 2.0]")))) |
++-------------------------------------------------------------------------+
+| [1,2]                                                                   |
++-------------------------------------------------------------------------+
+
+SELECT vec_to_string(vec_scalar_mul(-0.5, parse_vec('[2.0, 4.0]')));
+
++----------------------------------------------------------------------------+
+| vec_to_string(vec_scalar_mul(Float64(-0.5),parse_vec(Utf8("[2.0, 4.0]")))) |
++----------------------------------------------------------------------------+
+| [-1,-2]                                                                    |
++----------------------------------------------------------------------------+
+
+SELECT vec_to_string(vec_scalar_mul(1, '[1.0, 2.0]'));
+
++------------------------------------------------------------+
+| vec_to_string(vec_scalar_mul(Int64(1),Utf8("[1.0, 2.0]"))) |
++------------------------------------------------------------+
+| [1,2]                                                      |
++------------------------------------------------------------+
+
+SELECT vec_to_string(vec_scalar_mul(-0.5, '[2.0, 4.0]'));
+
++-----------------------------------------------------------------+
+| vec_to_string(vec_scalar_mul(Float64(-0.5),Utf8("[2.0, 4.0]"))) |
++-----------------------------------------------------------------+
+| [-1,-2]                                                         |
++-----------------------------------------------------------------+
+

tests/cases/standalone/common/function/vector/vector_scalar.sql

@@ -9,3 +9,15 @@ SELECT vec_to_string(vec_scalar_add(-1.0, parse_vec('[1.0, 2.0]')));
 SELECT vec_to_string(vec_scalar_add(1, '[1.0, 2.0]'));
 
 SELECT vec_to_string(vec_scalar_add(-1, '[1.0, 2.0]'));
+
+SELECT vec_to_string(vec_scalar_mul(1.0, '[1.0, 2.0]'));
+
+SELECT vec_to_string(vec_scalar_mul(-0.5, '[2.0, 4.0]'));
+
+SELECT vec_to_string(vec_scalar_mul(1.0, parse_vec('[1.0, 2.0]')));
+
+SELECT vec_to_string(vec_scalar_mul(-0.5, parse_vec('[2.0, 4.0]')));
+
+SELECT vec_to_string(vec_scalar_mul(1, '[1.0, 2.0]'));
+
+SELECT vec_to_string(vec_scalar_mul(-0.5, '[2.0, 4.0]'));