Flaky: NativeLinAlg.dot matrix-vector ComplexFloat returns wrong result on Linux

[devcrocod]

Multik version

0.3.0

Module

multik-openblas

Platform

JVM

Operating System

Linux

Description

NativeLinAlg.dot for matrix-vector multiplication with ComplexFloat produces incorrect results intermittently on Linux (Ubuntu 22.04.5 LTS, gcc-12 12.3.0, JDK 21 Temurin). The test uses a 2x2 ComplexFloat matrix and a 2-element vector, asserting with epsilon 1e-4f. Failed in 2 out of 4 CI runs.

Reproducer

val matrix = mk.ndarray(
    mk[mk[ComplexFloat(1, 2), ComplexFloat(3, 4)],
        mk[ComplexFloat(5, 6), ComplexFloat(7, 8)]]
)
val vector = mk.ndarray(mk[ComplexFloat(1, 0), ComplexFloat(0, 1)])

val expected = mk.ndarray(mk[ComplexFloat(-3, 5), ComplexFloat(-3, 13)])

val actual = NativeLinAlg.dot(matrix, vector)
assertComplexFloatingNDArray(expected, actual, 1e-4f) // Fails intermittently

Additional information

Flaky — failed in 2/4 CI runs.
AssertionFailedError at NativeLinAlgTest.kt:270.
CI runs: 22511673326, 22511861936.
Environment: Ubuntu 22.04.5 LTS, gcc-12 (12.3.0), g++-12, JDK 21 Temurin, x86_64.