76 lines
2.6 KiB
Go
76 lines
2.6 KiB
Go
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// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: MIT
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package integrate
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import (
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"math"
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"strings"
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"testing"
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"sourcedock.dev/petrbalvin/tensor/internal/core"
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)
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// Regression pins: budgets that did not bound what they
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// promised, and non-finite states that integrated to no error.
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// TestIntegrateNDDimensionBudget: in 10 dimensions the root box alone
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// costs 5^10 + 3^10 evaluations, about five times the default budget,
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// before the first budget check could fire.
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func TestIntegrateNDDimensionBudget(t *testing.T) {
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lower := make([]float64, 10)
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upper := make([]float64, 10)
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for i := range upper {
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upper[i] = 1
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}
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f := func(x []float64) float64 { return 1 }
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_, err := IntegrateND(f, lower, upper, CubatureOptions{})
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if err == nil || !strings.Contains(err.Error(), "budget") {
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t.Fatalf("IntegrateND in 10 dimensions under the default budget: err = %v", err)
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}
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}
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// TestPDEStepCountBound: a dt far below tFinal/1e12 wrapped the step
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// count conversion, and the silently larger step ran past the wave
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// equation's CFL check.
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func TestPDEStepCountBound(t *testing.T) {
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u0, err := core.FromFloats([]float64{0, 1, 0, 1, 0}, 5)
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if err != nil {
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t.Fatal(err)
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}
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if _, err := IntegrateHeat1D(u0, 1, 0.1, 1, 1e-300, 2, 0, 0); err == nil || !strings.Contains(err.Error(), "1e12") {
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t.Fatalf("Heat1D with an unhonourable dt: err = %v", err)
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}
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u2, err := core.FromFloats([]float64{1, 2, 3, 4, 5, 6, 7, 8, 9}, 3, 3)
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if err != nil {
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t.Fatal(err)
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}
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if _, err := IntegrateHeat2D(u2, 1, 0.1, 0.1, 1, 1e-300, 2, 0, 0, 0, 0); err == nil || !strings.Contains(err.Error(), "1e12") {
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t.Fatalf("Heat2D with an unhonourable dt: err = %v", err)
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}
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}
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// TestPDEVerletRejectNonFinite: a NaN or Inf initial state flowed
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// through the stencils and published an all-NaN history with no error.
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func TestPDEVerletRejectNonFinite(t *testing.T) {
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bad, err := core.FromFloats([]float64{1, math.NaN(), 0, 1, 0}, 5)
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if err != nil {
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t.Fatal(err)
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}
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if _, err := IntegrateHeat1D(bad, 1, 0.1, 1, 0.1, 2, 0, 0); err == nil || !strings.Contains(err.Error(), "non-finite") {
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t.Fatalf("Heat1D on a NaN state: err = %v", err)
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}
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q, err := core.FromFloats([]float64{1, math.Inf(1)}, 2)
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if err != nil {
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t.Fatal(err)
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}
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p, err := core.FromFloats([]float64{0, 0}, 2)
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if err != nil {
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t.Fatal(err)
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}
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accel := func(x *core.Array) (*core.Array, error) { return core.Copy(x), nil }
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if _, _, err := IntegrateVerlet(accel, 0, 1, q, p, 2); err == nil || !strings.Contains(err.Error(), "non-finite") {
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t.Fatalf("Verlet on an Inf state: err = %v", err)
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}
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}
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