Trait GroupedReduction

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pub trait GroupedReduction:
    Any
    + Send
    + Sync {
    // Required methods
    fn new_empty(&self) -> Box<dyn GroupedReduction>;
    fn reserve(&mut self, additional: usize);
    fn resize(&mut self, num_groups: IdxSize);
    fn update_group(
        &mut self,
        values: &Series,
        group_idx: IdxSize,
    ) -> PolarsResult<()>;
    unsafe fn update_groups(
        &mut self,
        values: &Series,
        group_idxs: &[IdxSize],
    ) -> PolarsResult<()>;
    unsafe fn combine(
        &mut self,
        other: &dyn GroupedReduction,
        group_idxs: &[IdxSize],
    ) -> PolarsResult<()>;
    unsafe fn gather_combine(
        &mut self,
        other: &dyn GroupedReduction,
        subset: &[IdxSize],
        group_idxs: &[IdxSize],
    ) -> PolarsResult<()>;
    unsafe fn partition(
        self: Box<Self>,
        partition_sizes: &[IdxSize],
        partition_idxs: &[IdxSize],
    ) -> Vec<Box<dyn GroupedReduction>>;
    fn finalize(&mut self) -> PolarsResult<Series>;
    fn as_any(&self) -> &dyn Any;
}

Expand description

A reduction with groups.

Each group has its own reduction state that values can be aggregated into.

Required Methods§

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fn new_empty(&self) -> Box<dyn GroupedReduction>

Returns a new empty reduction.

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fn reserve(&mut self, additional: usize)

Reserves space in this GroupedReduction for an additional number of groups.

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fn resize(&mut self, num_groups: IdxSize)

Resizes this GroupedReduction to the given number of groups.

While not an actual member of the trait, the safety preconditions below refer to self.num_groups() as given by the last call of this function.

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fn update_group( &mut self, values: &Series, group_idx: IdxSize, ) -> PolarsResult<()>

Updates the specified group with the given values.

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unsafe fn update_groups( &mut self, values: &Series, group_idxs: &[IdxSize], ) -> PolarsResult<()>

Updates this GroupedReduction with new values. values[i] should be added to reduction self[group_idxs[i]].

§Safety

group_idxs[i] < self.num_groups() for all i.

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unsafe fn combine( &mut self, other: &dyn GroupedReduction, group_idxs: &[IdxSize], ) -> PolarsResult<()>

Combines this GroupedReduction with another. Group other[i] should be combined into group self[group_idxs[i]].

§Safety

group_idxs[i] < self.num_groups() for all i.

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unsafe fn gather_combine( &mut self, other: &dyn GroupedReduction, subset: &[IdxSize], group_idxs: &[IdxSize], ) -> PolarsResult<()>

Combines this GroupedReduction with another. Group other[subset[i]] should be combined into group self[group_idxs[i]].

§Safety

subset[i] < other.num_groups() for all i. group_idxs[i] < self.num_groups() for all i.

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unsafe fn partition( self: Box<Self>, partition_sizes: &[IdxSize], partition_idxs: &[IdxSize], ) -> Vec<Box<dyn GroupedReduction>>

Partitions this GroupedReduction into several partitions.

The ith group of this GroupedReduction should becomes the group_idxs[i] group in partition partition_idxs[i].

§Safety

partitions_idxs[i] < partition_sizes.len() for all i. group_idxs[i] < partition_sizes[partition_idxs[i]] for all i. Each partition p has an associated set of group_idxs, this set contains 0..partition_size[p] exactly once.

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