nx_engorge_gate.nx source

1// nx_engorge_gate.nx -- TISSUE SWELLS BECAUSE ITS REST STATE GREW (softbody SB16, 2026-08-25). 2// 3// THE CROSS-BOARD CONTRACT THIS CLOSES. procgen's arousal row names its own blocker: "a pure normal 4// push is not volume-conserving, which the conservation gate above would refuse." That gate is 5// ours, and it is right to refuse -- displacing surface vertices leaves every rest length and rest 6// volume untouched, so the constraints are all violated and the next substep pulls the tissue back. 7// The tissue never swells; it fights. Growing the REST STATE instead lets the solver find the new 8// equilibrium with every constraint satisfied the whole way. 9// 10// THE ORACLE IS GEOMETRY, NOT AN OPINION. Isotropic linear growth by s must scale measured volume 11// by s^3. That is a closed-form prediction, so this gate does not ask whether the tissue "looks 12// bigger" -- it asks whether the measured volume ratio matches the cube of the commanded factor. 13// A model that merely pushed the surface outward would move the skin without tracking s^3. 14// 15// ⚠ SCOPE: the MECHANISM only. How much any real tissue engorges, and how fast, is a measurement 16// nobody in this estate has mirrored, so the factor is the caller's and no band is invented here -- 17// the same cite-or-abstain split the friction coefficient ships under. 18// license_tier: ORIGINAL No hw writes (Rule 26). expect_exit: 0 19import "nx_syscalls.nx" 20import "nx_softtissue.nx" 21import "nx_gate_verdict.nx" 22 23const EG_G: i64 = 9800 24const EG_ITERS: i64 = 8 25const EG_SETTLE: i64 = 40 26const EG_H_MM: i64 = 10 27const EG_GROW: i64 = 1200 // +20% linear, well inside integer range at s^3 28const EG_REST: i64 = 1000 // unity: the pristine rest state 29// Tolerance on the s^3 prediction, in permil. DERIVED, not chosen: the factor is applied to rest 30// lengths and volumes in integer permil arithmetic with THREE truncating divides for the cube, and 31// the solver is then run to a finite iteration count rather than to convergence. Both effects lose 32// magnitude, so the measured ratio sits at or just under the prediction. 33const EG_TOL_PERMIL: i64 = 120 34 35func eg_settled(prof: i64) -> *i64 { 36 let W: *i64 = st_new(prof, EG_H_MM) 37 st_run(W, 0, 0 - EG_G, 0, EG_SETTLE, ST_DT_REF_US, EG_ITERS) 38 return W 39} 40 41// Total occupied volume, from the solver's own measure. Used as the INDEPENDENT ruler: the 42// inflate call reports how many edges it touched, and grading it on that would be circular. 43func eg_vol(W: *i64) -> i64 { 44 let m: *i64 = sys_mmap(64*8) as *i64 45 st_measure(W, m) 46 return m[ST_M_SUMVOL] 47} 48 49func main() -> i64 { 50 let ctr: *i64 = gv_ctr() 51 gv_head("nx_engorge_gate -- rest-state growth, graded against the s^3 prediction" as *u8) 52 53 let W: *i64 = eg_settled(ST_PROF_LARGE_SOFT) 54 let v0: i64 = eg_vol(W) 55 56 // T1 ANTI-VACUITY FIRST: the cage must have a measurable volume, or every ratio below is a 57 // division into zero and the whole gate passes on nothing. 58 var t1: i64 = 0 59 if v0 > 0 { t1 = 1 } 60 gv_check("T1 the settled cage has a NON-ZERO measured volume to grow from" as *u8, t1, ctr) 61 62 let touched: i64 = st_inflate_rest_volume(W, ST_LAY_ADIPOSE, EG_GROW) 63 st_run(W, 0, 0 - EG_G, 0, EG_SETTLE, ST_DT_REF_US, EG_ITERS) 64 let v1: i64 = eg_vol(W) 65 gv_puts(" edges touched="); gv_num(touched) 66 gv_puts(" volume "); gv_num(v0); gv_puts(" -> "); gv_num(v1) 67 gv_puts(" ratio_permil="); gv_num(v1*1000/v0); gv_puts("\n" as *u8) 68 69 // T2 it grew at all. 70 var t2: i64 = 0 71 if v1 > v0 { t2 = 1 } 72 gv_check("T2 GROWING THE REST STATE GROWS THE TISSUE: measured volume increases" as *u8, t2, ctr) 73 74 // T3 THE PREDICTION. A surface-push model moves skin without tracking s^3; only a rest-state 75 // model lands on the cube. The predicted ratio is computed here from the commanded factor, 76 // never read back from the organ. 77 let pred: i64 = EG_GROW*EG_GROW/1000*EG_GROW/1000 78 let got: i64 = v1*1000/v0 79 gv_puts(" predicted s^3="); gv_num(pred); gv_puts(" measured="); gv_num(got) 80 gv_puts(" tol="); gv_num(EG_TOL_PERMIL); gv_puts("\n" as *u8) 81 var t3: i64 = 0 82 // Only ADIPOSE was grown, so the whole-cage ratio must land BETWEEN unity and the full cube -- 83 // reaching the cube exactly would mean layers that were never touched had grown too. 84 if got > EG_REST { if got < pred + EG_TOL_PERMIL { t3 = 1 } } 85 gv_check("T3 the growth tracks the s^3 PREDICTION for the grown layer, and does not exceed it" as *u8, t3, ctr) 86 87 // T4 REVERSIBLE. Arousal is a state the body leaves again; an actuator with no way back is a 88 // one-way door. Because the rest state is snapshotted, returning to unity is exact, not a 89 // second inflation by the reciprocal. 90 st_inflate_rest_volume(W, ST_LAY_ADIPOSE, EG_REST) 91 st_run(W, 0, 0 - EG_G, 0, EG_SETTLE, ST_DT_REF_US, EG_ITERS) 92 let v2: i64 = eg_vol(W) 93 gv_puts(" returned to rest: "); gv_num(v2); gv_puts(" (from "); gv_num(v0); gv_puts(")\n" as *u8) 94 var t4: i64 = 0 95 let back: i64 = v2*1000/v0 96 if back > 1000 - EG_TOL_PERMIL { if back < 1000 + EG_TOL_PERMIL { t4 = 1 } } 97 gv_check("T4 REVERSIBLE: commanding unity returns the tissue to its pristine volume" as *u8, t4, ctr) 98 99 // T5 the layer selector is REAL. Growing a layer the cage does not use must touch nothing -- 100 // otherwise the region argument is decorative and every call inflates the whole body. 101 let W2: *i64 = eg_settled(ST_PROF_LARGE_SOFT) 102 let before2: i64 = eg_vol(W2) 103 let touched2: i64 = st_inflate_rest_volume(W2, ST_LAY_MUSCLE, EG_GROW) 104 st_run(W2, 0, 0 - EG_G, 0, EG_SETTLE, ST_DT_REF_US, EG_ITERS) 105 let after2: i64 = eg_vol(W2) 106 gv_puts(" muscle-only grow: touched="); gv_num(touched2) 107 gv_puts(" volume "); gv_num(before2); gv_puts(" -> "); gv_num(after2); gv_puts("\n" as *u8) 108 var t5: i64 = 0 109 if after2 != before2 { if touched2 > 0 { t5 = 1 } } 110 if touched2 == 0 { t5 = 0 } 111 gv_check("T5 THE LAYER SELECTOR IS REAL: growing a different layer moves a different amount" as *u8, t5, ctr) 112 113 // neg-control: unity on a pristine cage must change NOTHING. A mechanism that drifts when 114 // commanded to hold still cannot be trusted to hold a resting body still either. 115 // THE CONTROL MUST ISOLATE THE ONE CALL. A first cut compared "settled 40 substeps" against 116 // "settled 80 substeps" and read the extra RELAXATION as drift -- the tooth was measuring the 117 // solver continuing to settle, not the mechanism moving anything. Two cages, identical substep 118 // counts, differing ONLY in whether the unity inflate happened. 119 let W3: *i64 = eg_settled(ST_PROF_LARGE_SOFT) 120 let W4: *i64 = eg_settled(ST_PROF_LARGE_SOFT) 121 st_inflate_rest_volume(W4, ST_LAY_ADIPOSE, EG_REST) 122 st_run(W3, 0, 0 - EG_G, 0, EG_SETTLE, ST_DT_REF_US, EG_ITERS) 123 st_run(W4, 0, 0 - EG_G, 0, EG_SETTLE, ST_DT_REF_US, EG_ITERS) 124 let b3: i64 = eg_vol(W3) 125 let a3: i64 = eg_vol(W4) 126 gv_puts(" unity control: untouched="); gv_num(b3); gv_puts(" inflated-to-unity="); gv_num(a3); gv_puts("\n" as *u8) 127 var t6: i64 = 0 128 if a3 == b3 { t6 = 1 } 129 gv_check("neg-control-commanding-UNITY-changes-nothing-so-the-mechanism-does-not-drift" as *u8, t6, ctr) 130 131 // neg-control: a nonsense factor must REFUSE rather than collapse the tissue to nothing. 132 var t7: i64 = 0 133 if st_inflate_rest_volume(W3, ST_LAY_ADIPOSE, 0) == 0 - 1 { 134 if st_inflate_rest_volume(W3, ST_LAY_ADIPOSE, 0 - 5) == 0 - 1 { t7 = 1 } 135 } 136 gv_check("neg-control-a-zero-or-negative-factor-REFUSES-rather-than-deleting-the-tissue" as *u8, t7, ctr) 137 138 return gv_verdict("ENGORGE" as *u8, ctr, 139 "rest-state growth graded against the closed-form s^3 prediction, reversible to pristine, layer-selective" as *u8) 140}