[BUG] munmap_chunk(): invalid pointer

Open

#381 opened on Jan 13, 2025 0 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty: 4/5
Estimated time: 3-5 days
Newbie friendliness: 25/100

Issue type: Bug
Clarity: Needs clarification
Activity status: Stale
Tech stack: rust
Domain: backend

Research direction

Start by reproducing the long-running program under the OpenCL backend with AF_TRACE=all and AF_PRINT_ERRORS=1. Inspect the referenced src/backend/opencl/jit.cpp and src/backend/opencl/Kernel.hpp paths around the logged kernel launches, and confirm the invalid-pointer failure no longer occurs.

Written by the indexing model from the issue text.

Description

Bug

Description

I installed ArrayFire using AUR
I am experiencing this on OpenCL
No, I do not have a workaround.
The bug can be reproduced if the program is left running for a long enough time. However, the exact time that it happens tends to be random.
Most Recent Console Output:

[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [25,256,1,1] Global: [32,256,1] Local: [32,1,1] threads: 8192
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [25,256,1,1] Global: [32,256,1] Local: [32,1,1] threads: 8192
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [1,1,1,1] Global: [128,1,1] Local: [128,1,1] threads: 128
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching memCopy
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [1,1,1,1] Global: [128,1,1] Local: [128,1,1] threads: 128
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [1,1,1,1] Global: [128,1,1] Local: [128,1,1] threads: 128
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,1,1,1] Global: [256,1,1] Local: [128,1,1] threads: 256
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [25,256,1,1] Global: [32,256,1] Local: [32,1,1] threads: 8192
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [25,256,1,1] Global: [32,256,1] Local: [32,1,1] threads: 8192
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [25,256,1,1] Global: [32,256,1] Local: [32,1,1] threads: 8192
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2965] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [25,256,1,1] Global: [32,256,1] Local: [32,1,1] threads: 8192
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,256,1,1] Global: [256,128,1] Local: [128,1,1] threads: 32768
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching identity_kernel
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [65536,1,1,1] Global: [65536,1,1] Local: [128,1,1] threads: 65536
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,256,1,1] Global: [256,128,1] Local: [128,1,1] threads: 32768
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [65536,1,1,1] Global: [65536,1,1] Local: [128,1,1] threads: 65536
[kernel][1736790336][2966] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [65536,1,1,1] Global: [65536,1,1] Local: [128,1,1] threads: 65536
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [25,256,1,1] Global: [32,256,1] Local: [32,1,1] threads: 8192
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [256,256,1,1] Global: [256,128,1] Local: [128,1,1] threads: 32768
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching reduce_first_kernel
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching philoxGenerator
[kernel][1736790336][2967] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/jit.cpp:469 ] Launching : Dims: [6400,1,1,1] Global: [6400,1,1] Local: [128,1,1] threads: 6400
munmap_chunk(): invalid pointer
[kernel][1736790336][2968] [ /usr/src/debug/arrayfire/arrayfire-full-3.8.3/src/backend/opencl/Kernel.hpp:34 ] Launching identity_kernel
Aborted (core dumped)

Reproducible Code and/or Steps

This is what I believe might be causing the bug, but I am not exactly sure. Let me know if the full source code is needed.

/// A probabilistic implementation of the STDP algorithm for a bitwise linear layer.
pub fn probabilistic_bitwise_stdp<I: BitVolume, O: BitVolume>(
    synaptic_layers:              &mut [BitwiseLinear<I, O>],
    self_connected:               bool,
    presynaptic_trace:            &af::Array<f32>,
    dominant_postsynaptic_spikes: &af::Array<bool>,
    dopamine:                     f32,
    alpha:                        f32,
    learning_rate:                f32
    ) {

    // TODO:
    // When arrayfire supports 8-bit signed integers, migrate to that instead of 16-bit integers.

    // Go through each synaptic layer and modify its weights.
    let connections: usize = synaptic_layers.len();
    for (layer_idx, layer) in synaptic_layers.iter_mut().enumerate() {

        // Get the excitatory and inhibitory weights, and convert it to a trinary layer.
        let (excitatory, inhibitory): (af::Array<bool>, af::Array<bool>) = layer.weights_as_array();

        let mut weights: af::Array<i16> = af::constant(0, excitatory.dims());
                weights                 = af::selectl( 1.0, &excitatory, &weights);
                weights                 = af::selectl(-1.0, &inhibitory, &weights);

        // Normalize the trace and compute the LTP and LTD components.
        let trace_norm: af::Array<f32> = if connections == 1 {
            presynaptic_trace / af::max_all(presynaptic_trace).0
        } else {
            let sequences:   &[af::Seq<i32>] = &[af::Seq::default(), af::Seq::default(), af::Seq::default(), af::Seq::new(layer_idx as i32, layer_idx as i32, 1)];
            let trace_layer: af::Array<f32>  = af::index(presynaptic_trace, sequences);

            &trace_layer / af::max_all(&trace_layer).0
        };

        let ltp_trace: af::Array<f32> = af::exp(&trace_norm) - alpha;
        let ltd_trace: af::Array<f32> = af::exp(&(1.0f32 - &trace_norm)) - alpha;

        // Calculate update probabilities.
        let p_update_prob: af::Array<f32> = (ltp_trace - ltd_trace) * learning_rate * dopamine;
        let n_update_prob: af::Array<f32> = &p_update_prob * -1f32;

        // Generate random values for probabilistic update.
        // We use a uniform distribution to have an equal chance for all values to be generated.
        //
        // Using the random values, we'll then create a mask for different weight updates (positive and
        // negative).
        let random_values: af::Array<f32> = af::randu(weights.dims());

        let increase_mask: af::Array<bool> = af::lt(&random_values, &p_update_prob, false) & af::lt(&weights, & 1i16, false);
        let decrease_mask: af::Array<bool> = af::lt(&random_values, &n_update_prob, false) & af::gt(&weights, &-1i16, false);

        // Calculate delta weights
        let delta_weights: af::Array<i16> = increase_mask.cast::<i16>() - decrease_mask.cast::<i16>();

        // Apply winner_mask and identity_mask to delta_weights.
        let winner_mask:          af::Array<bool> = af::tile(&dominant_postsynaptic_spikes, af::dim4!(1, I::FSIZE as u64, 1, 1));
        let masked_delta_weights: af::Array<i16>  = if self_connected {
            let identity_mask: af::Array<i16> = (1f32 - af::identity::<i16>(af::dim4!(1, I::FSIZE as u64, O::FSIZE as u64, 1))).cast();

            &delta_weights 
                * &winner_mask.cast::<i16>() 
                * &identity_mask
        } else {
            &delta_weights
                * &winner_mask.cast::<i16>()
        };

        // Apply the masked delta weights to the weights.
        weights += masked_delta_weights;
        weights  = af::clamp(&weights, &-1i16, &1i16, true);

        // Deconstruct the weights back into their excitatory and inhibitory counterparts and export it
        // back into the layer.
        let excitatory: af::Array<bool> = af::eq(&weights, & 1, false);
        let inhibitory: af::Array<bool> = af::eq(&weights, &-1, false);

        layer.update_weights(excitatory, inhibitory);
    }
}

    /// Returns the weights as an arrayfire array of the dimensions (1, input size, output size).
    /// Arrays are returned in the order of excitatory and inhibitory weights.
    pub fn weights_as_array(&self) -> (af::Array<bool>, af::Array<bool>) {
        (
            af::Array::new(
                &self.neurons.par_iter()
                    .flat_map(|neuron| neuron.weight_excitatory.to_flattened_bits())
                    .collect::<Vec<_>>(),
                af::dim4!(1, I::FSIZE as u64, O::FSIZE as u64)
            ),
            af::Array::new(
                &self.neurons.par_iter()
                    .flat_map(|neuron| neuron.weight_inhibitory.to_flattened_bits())
                    .collect::<Vec<_>>(),
                af::dim4!(1, I::FSIZE as u64, O::FSIZE as u64)
            )
        )
    }

    /// Updates the weights from an arrayfire array of the dimensions (input size, output size).
    pub fn update_weights(&mut self, updated_excitatory: af::Array<bool>, updated_inhibitory: af::Array<bool>) {
        let mut excitatory_weights: Vec<bool> = vec![false; (I::FSIZE * O::FSIZE) as usize];
        let mut inhibitory_weights: Vec<bool> = vec![false; (I::FSIZE * O::FSIZE) as usize];

        updated_excitatory.host(&mut excitatory_weights);
        updated_inhibitory.host(&mut inhibitory_weights);

        self.neurons.par_iter_mut().enumerate().for_each(|(i, neuron)| {
            let start: usize = i     * I::FSIZE as usize;
            let end:   usize = start + I::FSIZE as usize;

            let excitatory_slice: &[bool] = &excitatory_weights[start..end];
            let inhibitory_slice: &[bool] = &inhibitory_weights[start..end];

            neuron.weight_excitatory = I::from_flattened_bits(excitatory_slice).unwrap();
            neuron.weight_inhibitory = I::from_flattened_bits(inhibitory_slice).unwrap();
        });
    }

System Information

Arrayfire 3.8.3
I have an NVidia 3050 RTX laptop GPU
Output as follows:

LSB Version:	n/a
Distributor ID:	Arch
Description:	Arch Linux
Release:	rolling
Codename:	n/a
name, memory.total [MiB], driver_version
NVIDIA GeForce RTX 3050 Laptop GPU, 4096 MiB, 565.57.01
rocm-smi not found.
clinfo not found.

Checklist

Using the latest available ArrayFire release
GPU drivers are up to date

Dominant language: Rust
Stars: 827
Forks: 59
PR merge metrics: No merged PRs in 30d

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