recommend(): 0.5 GB tolerance so nameplate min_vram tiers are reachable

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: diffuseR
 Title: Functional Interface to Diffusion Models in R
-Version: 0.2.2.1
+Version: 0.2.2.2
 Authors@R: c(
     person("Troy", "Hernandez", email = "troy@cornball.ai", role = c("aut", "cre"),
            comment = c(ORCID = "0009-0005-4248-604X")),

NEWS.md

@@ -1,3 +1,12 @@
+# diffuseR 0.2.2.2
+
+* `recommend()` tier selection now applies a 0.5 GB tolerance to the
+  `min_vram` thresholds (#56). The thresholds are nameplate card sizes,
+  but detection reports free VRAM and no card reports its nameplate as
+  free, so every nameplate-valued tier (the flux-family 8 GB tiers, the
+  SDXL 12 GB tier, the flux2 bf16 16 GB tier) was unreachable on
+  exactly the card it targets and silently dropped to the CPU tier.
+
 # diffuseR 0.2.2.1
 
 * `txt2img()` and `img2img()` now `match.arg()` their `model_name`, so

R/recommend.R

@@ -93,7 +93,12 @@ recommend <- function(model = c("sd21", "sdxl", "flux1", "flux2", "zimage",
     chosen <- NULL
     want <- NULL # first VRAM-eligible tier blocked by a missing read cap
     for (tier in tiers) {
-        if (vram_gb < tier$min_vram) {
+        # min_vram values are nameplate card sizes (8, 12, 16...), but
+        # vram_gb is FREE VRAM, and no card reports its nameplate as
+        # free (an 8 GB card shows ~7.5-7.9). Without the 0.5 GB
+        # tolerance every nameplate-valued tier is unreachable on
+        # exactly the card it targets (#56).
+        if (vram_gb < tier$min_vram - 0.5) {
             next
         }
         need <- tier$needs

inst/tinytest/test_recommend.R

@@ -19,6 +19,17 @@ expect_true(all(c("precision", "devices", "offload", "max_pixels",
   names(r)))
 expect_true(is.integer(r$max_pixels) || is.numeric(r$max_pixels))
 
+# --- nameplate tiers reachable on their own cards (#56) --------------------------
+
+# min_vram thresholds are nameplate sizes, but detection reports free
+# VRAM: a real 8 GB card shows ~7.5-7.9 free. The 0.5 GB tolerance keeps
+# the 8 GB tier selectable there; below the tolerance drops to CPU.
+r8 <- recommend("flux2", vram_gb = 7.6, st_caps = cran)
+expect_equal(r8$devices$transformer, "cuda")
+expect_equal(r8$precision, "nf4")
+r7 <- recommend("flux2", vram_gb = 7.4, st_caps = cran)
+expect_true(all(unlist(r7$devices) == "cpu"))
+
 # --- floors: nf4 for the quantized families, fp16 for SD -------------------------
 
 # No GPU: everything runs on CPU at its floor precision, no fork nag.