…ckend

Shipped configs contain sweep-produced floats (e.g. num_layers = 2.11327
in cartpole.ini). The native backend truncates them on assignment to C
ints; the torch backend passed them straight to nn.Linear and crashed
with 'float object cannot be interpreted as an integer'. Fixes the torch
(--slowly) backend for 17 of the 38 currently-buildable ocean envs, on
all platforms.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Include paths (pybind11, numpy, sysconfig) and the torch libomp lookup
used bare 'python', which fails with ModuleNotFoundError when the target
venv is not the active interpreter. Resolve once at the top:
PYTHON=$path ./build.sh <env> --cpu now works from any shell.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding: OBS_SIZE 1 (ByteTensor), one discrete
head of 2 (ACT_SIZES {2}). Env struct gains num_agents/rng and switches
actions/terminals to the float pointers vecenv assigns. No config keys
needed beyond the existing size.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding: OBS_SIZE 256 (4 features x NUM_BOIDS=64,
guarded against config mismatch at init), ACT_SIZES {5, 5}. Env struct
gains num_agents/rng and switches terminals to the float pointer vecenv
assigns. The (action - 2)/4 scaling the deleted python wrapper applied
moves into c_step so raw discrete actions keep the same velocity deltas.
report_interval added to the config with the old python default (1).

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding: OBS_SIZE 100 (3*NUM_ARMIES=2 + 4*16 + 22
+ 8, guarded against config mismatch at init), ACT_SIZES {1, 1, 1}
(continuous 3-vector, was Box(-1, 1, (3,))). num_agents on the struct
now means learner buffer rows as vecenv requires; a new num_entities
field (2x, matching the num_agents*2 the 3.x wrapper passed to C)
covers the scripted opponent half, so the old num_agents/num_agents/2
loops become num_entities/num_agents. terminals switches to the float
pointer vecenv assigns, rng added, the stale compute_observations
stride assert corrected, and attack_aa gains its missing return false
(now an error under -Werror=return-type). width/height added to the
config with the old python defaults (1920/1080).

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding: OBS_SIZE 64 (8x8 board, uint8/ByteTensor),
one discrete head of 512 (size*size*8 move types). Env struct gains
num_agents/rng and switches actions/terminals to the float pointers
vecenv assigns; standalone demo checkers.c updated to match. No config
keys added (size=8 already present).

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding: OBS_SIZE 1 (float32/FloatTensor), one
discrete head of 2. Env struct gains num_agents/rng and switches
actions/terminals to the float pointers vecenv assigns; standalone demo
memory.c updated to match. Config: add length=4 (old python default) to
config/memory.ini, and drop the stale "memory" entry from
config/sanity.ini's env_name list (a 3.x leftover whose envs no longer
exist) — it glob-matched before memory.ini in load_config, handing the
env an empty [env] section and crashing my_init's dict_get("length").

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding: OBS_SIZE 1 (uint8/ByteTensor, constant
zero obs), one discrete head of 2 (left/right). Env struct gains
num_agents/rng and switches actions/terminals to the float pointers
vecenv assigns; allocate_World updated to match. No config keys added
(mean_left/mean_right/var_right already present).

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding (OBS_SIZE 21, MultiDiscrete heads {9,5}).
Env struct gains rng and switches actions/terminals to the float
pointers vecenv assigns. num_agents already present in config.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding (OBS_SIZE 49 = (2*vision+1)^2 with
vision 3, ByteTensor obs, one discrete head of 5). Env struct gains
rng and switches actions/terminals to the float pointers vecenv
assigns; terminal memsets updated for float width. No cross-env
shared state — each env owns its grid, so the default my_vec_init
path suffices. Config: num_agents changed from the old python-list
[8] to scalar 8 (C dict values are doubles); width/height added with
the old python defaults (32).

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding (OBS_SIZE 10, ByteTensor obs, one
discrete head of 4, matching the old python wrapper spec). Env struct
gains rng and switches actions/terminals to the float pointers vecenv
assigns. Adds the previously missing c_close (frees the render client
if open); no config keys needed — my_init reads no kwargs, mirroring
the old no-arg my_init.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Rewrite binding.c from the 3.x env_binding.h CPython glue to the 4.0
vecenv.h compile-time binding (OBS_SIZE 4 uint8 obs as ByteTensor, one
discrete head of 3). Env struct gains num_agents/rng and switches
actions/terminals to the float pointers vecenv assigns; the standalone
allocator follows suit. c_reset already writes initial observations.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Replace the stale OBS_TYPE/ACT_TYPE macros with the OBS_TENSOR_T
ByteTensor define vecenv.h now expects, switch the actions pointer
from double* to the float* vecenv assigns, and add the rng field
vecenv seeds per env.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Replace the stale OBS_TYPE/ACT_TYPE macros with the OBS_TENSOR_T
FloatTensor define vecenv.h now expects, switch the actions pointer
(struct and standalone allocator) from double* to the float* vecenv
assigns, and add the rng field vecenv seeds per env.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Replace stale OBS_TYPE/ACT_TYPE defines with OBS_TENSOR_T ByteTensor
(env writes unsigned char observations). Add unsigned int rng to
CSnake (vecenv seeds envs[i].rng) and switch actions to float* /
observations to unsigned char* to match the vecenv buffer types
under -Werror=incompatible-pointer-types.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Replace stale OBS_TYPE/ACT_TYPE defines with OBS_TENSOR_T FloatTensor
and switch actions to float* to match vecenv buffer types under
-Werror=incompatible-pointer-types. Add the [env] keys my_init reads
that were missing from config/whisker_racer.ini (llw_ang, flw_ang,
frw_ang, rrw_ang, render, i), using the old Python-side defaults;
dict_get asserts on missing keys.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

Add unsigned int rng (vecenv seeds envs[i].rng) and the num_goals
field binding.c sets to the Scape struct, and switch actions to
float* to match the vecenv action buffer under
-Werror=incompatible-pointer-types.

Add config/scape.ini: [vec]/[train] modeled on pong/snake with a
modest total_agents, [env] providing the width/height keys my_init
reads (1080x720, matching the old scape.c demo defaults).

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

craftax_classic.h unconditionally included <immintrin.h> and used ~44
AVX-512 intrinsics in the Perlin worldgen block of generate_world(),
which broke compilation on arm64 (Apple Silicon).

Guard structure:
- The <immintrin.h> include and a new CRAFTAX_AVX512 macro are gated on
  __AVX512F__ or (x86/x86_64 + GCC/Clang), since build.sh compiles with
  only -mavx2 and the intrinsics are enabled per-function via
  __attribute__((target("avx512f,..."))), which is now gated the same way.
- Inside generate_world(), a single #if CRAFTAX_AVX512 / #else / #endif
  wraps the noise-generation block: the original AVX-512 code on x86, a
  lane-for-lane scalar equivalent elsewhere. Each vector lane maps to one
  column (c = c_base + lane); _mm512_cvttps_epi32 becomes int truncation,
  the fmsub/fmadd polynomial is perlin_interp(fy), and
  _mm512_permutexvar_ps(yN, load(&tab[k][rowM])) becomes tab[k][rowM+yN].
  Function signature and call sites are unchanged.

Verified: ./build.sh craftax_classic --cpu builds on arm64 and the MPS
smoke test prints OK steps=524288.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn

nproc does not exist on macOS; the nethack NLE build step failed before
even reaching the compiler. (The NLE build itself still fails on macOS
inside the vendored NetHack fork's C++ visibility attributes — upstream
NLE has no macOS support — but the build script bug is real regardless.)

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_019AsyRcLQqeJondzSTM6xsn