stop overriding JAX GPU memory preallocation

Author: t-kalinowski

NEWS.md

@@ -1,5 +1,9 @@
 # keras3 (development version)
 
+- On Linux, `use_backend("jax", gpu = TRUE)` no longer overrides
+  `XLA_PYTHON_CLIENT_MEM_FRACTION`, preserving the JAX default or a
+  user-provided value.
+
 # keras3 1.5.1
 
 - `use_backend("jax")` on macOS now defaults to `gpu = FALSE`, so `jax-metal`

R/install.R

@@ -245,7 +245,6 @@ use_backend <- function(backend, gpu = NA) {
         gpu <- has_gpu()
 
       if (gpu) {
-        Sys.setenv("XLA_PYTHON_CLIENT_MEM_FRACTION" = "1.00")
         py_require(c("jax[cuda12]!=0.6.1"))
       } else {
         py_require(c("jax[cpu]"))