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use super::{matmatadd, matmatdiv, matmatmul, matmatsub, Matrix};
#[derive(Debug, Clone, Copy)]
pub enum Broadcast {
Hstack(usize),
Vstack(usize),
IsScalar,
None,
Invalid,
}
pub(crate) fn calc_broadcast_shape(m1: &Matrix, m2: &Matrix) -> [Broadcast; 2] {
if m1.shape() == m2.shape() {
[Broadcast::None, Broadcast::None]
} else if m1.shape().contains(&1) {
if m1.nrows == 1 {
assert!(
m1.ncols == m2.ncols // single vstack broadcast for m1
|| m2.ncols == 1 // vstack broadcast m1 and hstack broadcast m2
|| m1.ncols == 1 // m1 is just a single element matrix, vstack and hstack it.
);
if m1.ncols == m2.ncols {
[Broadcast::Vstack(m2.nrows), Broadcast::None]
} else if m2.ncols == 1 {
[Broadcast::Vstack(m2.nrows), Broadcast::Hstack(m1.ncols)]
} else if m1.ncols == 1 {
[Broadcast::IsScalar, Broadcast::None]
} else {
[Broadcast::Invalid, Broadcast::Invalid]
}
} else {
// m1.ncols == 1
assert!(
m1.nrows == m2.nrows // single hstack broadcast for m1
|| m2.nrows == 1 // hstack broadcast m1 and vstack broadcast m2
|| m1.nrows == 1 // m1 is just a single element matrix
);
if m1.nrows == m2.nrows {
[Broadcast::Hstack(m2.ncols), Broadcast::None]
} else if m2.nrows == 1 {
[Broadcast::Hstack(m2.ncols), Broadcast::Vstack(m1.nrows)]
} else if m1.nrows == 1 {
[Broadcast::IsScalar, Broadcast::None]
} else {
[Broadcast::Invalid, Broadcast::Invalid]
}
}
} else if m2.shape().contains(&1) {
let [b1, b2] = calc_broadcast_shape(m2, m1);
[b2, b1]
} else {
[Broadcast::Invalid, Broadcast::Invalid]
}
}
macro_rules! broadcast_op {
($op: tt, $fnname: ident, $matmatfn: ident) => {
pub(crate) fn $fnname(m1: &Matrix, m2: &Matrix) -> Matrix {
let b = calc_broadcast_shape(m1, m2);
match b {
[Broadcast::None, Broadcast::None] => {
assert_eq!(m1.shape(), m2.shape());
// easy, do nothing special
$matmatfn(m1, m2)
}
[Broadcast::Hstack(hstack), Broadcast::None] => {
assert_eq!(hstack, m2.ncols);
let mut new = m2.clone();
// each element in m1 gets added to each row in m2
// . ....
// . ....
// . ....
// . ....
for i in 0..m1.nrows {
new.apply_along_row(i, |x| m1[i][0] $op x)
}
new
}
[Broadcast::Vstack(vstack), Broadcast::None] => {
assert_eq!(vstack, m2.nrows);
let mut new = m2.clone();
// each element in m1 gets added to each column in m2
// .... ....
// ....
// ....
// ....
for i in 0..new.nrows {
new[i].iter_mut().zip(&m1[0]).for_each(|(x, y)| *x = y $op *x);
}
new
}
[Broadcast::None, Broadcast::Hstack(hstack)] => {
assert_eq!(hstack, m1.ncols);
let mut new = m1.clone();
// each element in m1 gets added to each row in m2
// .... .
// .... .
// .... .
// .... .
for i in 0..m2.nrows {
new.apply_along_row(i, |x| x $op m2[i][0])
}
new
},
[Broadcast::None, Broadcast::Vstack(vstack)] => {
assert_eq!(vstack, m1.nrows);
let mut new = m1.clone();
// each element in m1 gets added to each column in m2
// .... ....
// ....
// ....
// ....
for i in 0..new.nrows {
new[i].iter_mut().zip(&m2[0]).for_each(|(x, y)| *x = *x $op y);
}
new
},
[Broadcast::Hstack(hstack), Broadcast::Vstack(vstack)] => {
assert_eq!(m2.ncols, hstack);
assert_eq!(m1.nrows, vstack);
assert_eq!(m2.nrows, 1);
assert_eq!(m1.ncols, 1);
// . . . .
// .
// .
// .
let mut new = Matrix::zeros(m1.nrows, m2.ncols);
for i in 0..new.nrows {
for j in 0..new.ncols {
new[i][j] = m1[i][0] $op m2[0][j]
}
}
new
}
[Broadcast::Vstack(vstack), Broadcast::Hstack(hstack)] => {
assert_eq!(m1.ncols, hstack);
assert_eq!(m2.nrows, vstack);
assert_eq!(m1.nrows, 1);
assert_eq!(m2.ncols, 1);
// . . . .
// .
// .
// .
let mut new = Matrix::zeros(m2.nrows, m1.ncols);
for i in 0..new.nrows {
for j in 0..new.ncols {
new[i][j] = m1[0][j] $op m2[i][0]
}
}
new
}
[Broadcast::IsScalar, _] => {
// 2nd broadcast should always be Broadcast::None
assert!(m1.nrows == 1 && m1.ncols == 1);
m1[0][0] $op m2
}
[_, Broadcast::IsScalar] => {
// 1st broadcast should always be Broadcast::None
assert!(m2.nrows == 1 && m2.ncols == 1);
m1 $op m2[0][0]
}
_ => {
// one of them is invalid, or have [hstack, hstack] or [vstack, vstack], neither
// of which are possible
panic!("invalid broadcast shape")
}
}
}
};
}
broadcast_op!(+, broadcast_add, matmatadd);
broadcast_op!(-, broadcast_sub, matmatsub);
broadcast_op!(*, broadcast_mul, matmatmul);
broadcast_op!(/, broadcast_div, matmatdiv);
#[cfg(test)]
mod tests {
use super::super::super::arange;
use super::super::Vector;
use super::*;
#[test]
fn test_broadcast_1() {
let mut a = Matrix::new([8., 9., 2., 5., 4., 9., 1., 6., 3.], 3, 3);
let mut b = Vector::new([1., 2., 3.]).to_matrix(); // 1x3 matrix
let c = broadcast_add(&a, &b);
assert_eq!(c, Matrix::new([9., 11., 5., 6., 6., 12., 2., 8., 6.], 3, 3));
let d = broadcast_mul(&a, &b);
assert_eq!(
d,
Matrix::new([8., 18., 6., 5., 8., 27., 1., 12., 9.], 3, 3)
);
b.t_mut(); // 3x1
let e = broadcast_sub(&b, &a);
assert_eq!(
e,
Matrix::new([-7., -8., -1., -3., -2., -7., 2., -3., 0.], 3, 3)
);
a.reshape_mut(1, -1); // flatten to 9x1
let f = broadcast_div(&a, &b);
assert_eq!(
f,
Matrix::new(
vec![
8.,
9.,
2.,
5.,
4.,
9.,
1.,
6.,
3.,
4.,
4.5,
1.,
2.5,
2.,
4.5,
0.5,
3.,
1.5,
2. + 2. / 3.,
3.,
2. / 3.,
1. + 2. / 3.,
1. + 1. / 3.,
3.,
1. / 3.,
2.,
1.
],
3,
9
)
);
}
#[test]
fn test_broadcast_2() {
let a = Matrix::new(
[
-0.699, -1.031, 1.235, 0.328, 0.026, 0.046, 1.501, 0.438, 1.304, 0.728, 1., -0.417,
-0.265, 0.091, 0.422, 0.602,
],
4,
4,
);
let b = Matrix::new([0.896, 0.488, 0.577, 0.316], 4, 1);
let c = broadcast_sub(&a, &b);
assert_eq!(
c,
Matrix::new(
[
-1.595, -1.927, 0.339, -0.568, -0.462, -0.442, 1.013, -0.05, 0.727, 0.151,
0.423, -0.994, -0.581, -0.225, 0.106, 0.286
],
4,
4
)
);
let d = broadcast_sub(&a, &b.t());
assert_eq!(
d,
Matrix::new(
[
-1.595, -1.519, 0.658, 0.012, -0.87, -0.442, 0.924, 0.122, 0.408, 0.24, 0.423,
-0.733, -1.161, -0.397, -0.155, 0.286
],
4,
4
)
);
let e = broadcast_div(&b, &a);
assert_eq!(
e,
Matrix::new(
[
-1.2818311874105868,
-0.86905916585839,
0.7255060728744939,
2.7317073170731705,
18.76923076923077,
10.608695652173912,
0.3251165889407062,
1.1141552511415524,
0.44248466257668706,
0.7925824175824175,
0.577,
-1.3836930455635492,
-1.1924528301886792,
3.4725274725274726,
0.7488151658767773,
0.5249169435215947
],
4,
4
)
);
let f = broadcast_div(&a.t(), &b);
assert_eq!(
f,
Matrix::new(
[
-0.7801339285714285,
0.02901785714285714,
1.4553571428571428,
-0.2957589285714286,
-2.1127049180327866,
0.0942622950819672,
1.4918032786885247,
0.1864754098360656,
2.1403812824956674,
2.601386481802426,
1.733102253032929,
0.7313691507798961,
1.0379746835443038,
1.3860759493670887,
-1.3196202531645569,
1.9050632911392404
],
4,
4
)
);
}
#[test]
fn test_broadcast_3() {
let a = Matrix::new([1., 2., 3., 4.], 2, 2);
let b = Matrix::new([3., 4., 1., 1.], 2, 2);
let c = broadcast_add(&a, &b);
assert_eq!(c, Matrix::new([4., 6., 4., 5.], 2, 2));
let d = broadcast_sub(&a, &b.t());
assert_eq!(d, Matrix::new([-2., 1., -1., 3.], 2, 2));
let e = broadcast_div(&a.t(), &b);
assert_eq!(e, Matrix::new([1. / 3., 0.75, 2., 4.], 2, 2));
}
#[test]
fn test_broadcast_4() {
let a = arange(0., 4., 1.).to_matrix().reshape(1, 4);
let b = arange(0., 4., 1.).to_matrix().reshape(4, 1);
let c = broadcast_sub(&a, &b);
assert_eq!(
c,
Matrix::new(
[0., 1., 2., 3., -1., 0., 1., 2., -2., -1., 0., 1., -3., -2., -1., 0.],
4,
4
)
);
let d = broadcast_mul(&a, &b.t());
assert_eq!(d, Matrix::new([0., 1., 4., 9.], 1, 4));
let e = broadcast_add(&b, &a.t());
assert_eq!(e, Matrix::new([0., 2., 4., 6.], 4, 1));
}
}