35 lines
1.0 KiB
Go
35 lines
1.0 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 linalg
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import (
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"math"
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"testing"
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)
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// TestDetFactorsThroughParallelDispatch drives base.Factor's rank-1
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// update dispatch through the public Det entry: a 200 by 200 upper
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// triangular matrix keeps every pivot on the diagonal, and the first
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// pivot's update spans 199 rows times 200 columns, past the dispatch
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// quantum, so the crewed path runs rather than the inline one. No row
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// changes under the elimination, since the multiplier of every row is
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// zero, so the determinant is exactly 2 to the 200th, which float64
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// holds as an exact power of two.
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func TestDetFactorsThroughParallelDispatch(t *testing.T) {
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const n = 200
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vals := make([]float64, n*n)
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for i := range n {
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for j := i; j < n; j++ {
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vals[i*n+j] = 2
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}
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}
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d, err := Det(mustFloats(t, vals, n, n))
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if err != nil {
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t.Fatalf("Det: %v", err)
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}
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if want := math.Ldexp(1, 200); d != want {
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t.Fatalf("Det = %v, want exactly %v", d, want)
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}
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}
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