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combin: Change Cartesian to deal with indices (#1059)

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Fixes #1057.
This commit is contained in:
Brendan Tracey
2019-08-17 12:41:00 +01:00
committed by GitHub
parent 01f78999a4
commit b0ff1e7714
2 changed files with 48 additions and 92 deletions
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85
stat/combin/combin_test.go
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@@ -10,7 +10,6 @@ import (
"testing"
"gonum.org/v1/gonum/floats"
"gonum.org/v1/gonum/mat"
)
// intSosMatch returns true if the two slices of slices are equal.
@@ -184,62 +183,36 @@ func TestCombinationGenerator(t *testing.T) {
func TestCartesian(t *testing.T) {
// First, test with a known return.
data := [][]float64{
{1, 2},
{3, 4},
{5, 6},
lens := []int{2, 3, 4}
want := [][]int{
{0, 0, 0},
{0, 0, 1},
{0, 0, 2},
{0, 0, 3},
{0, 1, 0},
{0, 1, 1},
{0, 1, 2},
{0, 1, 3},
{0, 2, 0},
{0, 2, 1},
{0, 2, 2},
{0, 2, 3},
{1, 0, 0},
{1, 0, 1},
{1, 0, 2},
{1, 0, 3},
{1, 1, 0},
{1, 1, 1},
{1, 1, 2},
{1, 1, 3},
{1, 2, 0},
{1, 2, 1},
{1, 2, 2},
{1, 2, 3},
}
want := mat.NewDense(8, 3, []float64{
1, 3, 5,
1, 3, 6,
1, 4, 5,
1, 4, 6,
2, 3, 5,
2, 3, 6,
2, 4, 5,
2, 4, 6,
})
got := Cartesian(nil, data)
if !mat.Equal(want, got) {
t.Errorf("cartesian data mismatch.\nwant:\n%v\ngot:\n%v", mat.Formatted(want), mat.Formatted(got))
}
gotTo := mat.NewDense(8, 3, nil)
Cartesian(gotTo, data)
if !mat.Equal(want, got) {
t.Errorf("cartesian data mismatch with supplied.\nwant:\n%v\ngot:\n%v", mat.Formatted(want), mat.Formatted(gotTo))
}
// Test that Cartesian generates unique vectors.
for cas, data := range [][][]float64{
{{1}, {2, 3}, {8, 9, 10}},
{{1, 10}, {2, 3}, {8, 9, 10}},
{{1, 10, 11}, {2, 3}, {8}},
} {
cart := Cartesian(nil, data)
r, c := cart.Dims()
if c != len(data) {
t.Errorf("Case %v: wrong number of columns. Want %v, got %v", cas, len(data), c)
}
wantRows := 1
for _, v := range data {
wantRows *= len(v)
}
if r != wantRows {
t.Errorf("Case %v: wrong number of rows. Want %v, got %v", cas, wantRows, r)
}
for i := 0; i < r; i++ {
for j := i + 1; j < r; j++ {
if floats.Equal(cart.RawRowView(i), cart.RawRowView(j)) {
t.Errorf("Cas %v: rows %d and %d are equal", cas, i, j)
}
}
}
cartTo := mat.NewDense(r, c, nil)
Cartesian(cartTo, data)
if !mat.Equal(cart, cartTo) {
t.Errorf("cartesian data mismatch with supplied.\nwant:\n%v\ngot:\n%v", mat.Formatted(cart), mat.Formatted(cartTo))
}
got := Cartesian(lens)
if !intSosMatch(want, got) {
t.Errorf("cartesian data mismatch.\nwant:\n%v\ngot:\n%v", want, got)
}
}