49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: MIT
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package optim
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import (
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"math"
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"testing"
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"sourcedock.dev/petrbalvin/tensor/internal/core"
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)
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// MinimiseLinearRows hands both standard rows of a two-sided constraint
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// slots in the one backing block, taken in build order. A fixture with
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// a two-sided row and a one-sided row pins the hand-computed optimum,
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// which a row that aliased its neighbour could not reach.
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func TestMinimiseLinearRowsTwoSidedConstraint(t *testing.T) {
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// minimise x1 - 2*x2 over 2 ≤ x1 + x2 ≤ 3 and 0 ≤ x1 ≤ 1: the
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// objective pushes x2 up and x1 down, so x1 = 0, x2 = 3 and the
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// optimum is -6.
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cost, err := core.FromFloats([]float64{1, -2}, 2)
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if err != nil {
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t.Fatalf("FromFloats: %v", err)
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}
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a, err := core.FromFloats([]float64{1, 1, 1, 0}, 2, 2)
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if err != nil {
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t.Fatalf("FromFloats: %v", err)
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}
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cons := LinearConstraints{
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A: a,
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Lower: []float64{2, 0},
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Upper: []float64{3, 1},
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}
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x, value, merr := MinimiseLinearRows(cost, cons, LinearProgramOptions{})
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if merr != nil {
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t.Fatalf("MinimiseLinearRows: %v", merr)
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}
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if math.Abs(value+6) > 1e-9 {
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t.Fatalf("optimum = %v, want -6", value)
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}
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if v := x.FloatAt(0); math.Abs(v) > 1e-9 {
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t.Fatalf("x1 = %v, want 0", v)
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}
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if v := x.FloatAt(1); math.Abs(v-3) > 1e-9 {
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t.Fatalf("x2 = %v, want 3", v)
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}
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}
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