feat: implement dual-seed PRNG isolation for clinical allocations and subject ID generation

Validation_Traceability_Matrix.md

@@ -1,6 +1,6 @@
 # Validation Traceability Matrix
 
-> **Generated:** 2026-08-13T15:02:47.631Z  
+> **Generated:** 2026-08-13T15:02:54.350Z  
 > **Status:** Test results not provided — status shown as UNKNOWN  
 > **Requirements covered:** 14 / 16  
 > **Tagged test cases:** 39  

src/app/domain/randomization-engine/core/minimization-algorithm.ts

@@ -3,6 +3,7 @@ import { RandomizationConfig, GeneratedSchema, TreatmentArm } from '../../core/m
 import { PRECISION_SCALE } from '../../../core/constants/precision.config';
 import { generateSubjectId } from './subject-id-engine';
 import { SubjectRegistry } from './subject-registry';
+import { MT19937Internal } from './mt19937';
 
 import { MathUtil } from '../../core/utils/math.util';
 
@@ -87,8 +88,15 @@ export function generateMinimization(
   config: RandomizationConfig,
   rng: () => number,
   registry: SubjectRegistry,
-  siteWeights?: Record<string, number>
+  siteWeights?: Record<string, number>,
+  rngId?: () => number
 ): GeneratedSchema[] {
+  const resolvedRngId = rngId ?? (config.seed ? (() => {
+    const secondarySeed = config.seed + '-id';
+    const mtSecondary = new MT19937Internal(MT19937Internal.get31BitSeed(secondarySeed));
+    return () => mtSecondary.random();
+  })() : rng);
+
   const { arms, strata, sites, minimizationConfig } = config;
   const p = minimizationConfig?.p ?? 0.8;
   const totalSampleSize = minimizationConfig?.totalSampleSize ?? 100;
@@ -348,7 +356,7 @@ export function generateMinimization(
       config.subjectIdMask,
       { site, stratumCode, sequence: siteSeq },
       usedSubjectIds,
-      rng
+      resolvedRngId
     );
 
     schema.push({

src/app/domain/randomization-engine/core/randomization-algorithm.spec.ts

@@ -993,5 +993,28 @@ describe('generateRandomizationSchema – hierarchical block strategy', () => {
       expect(() => generateRandomizationSchema(config)).toThrow(/marginalCap/i);
     });
   });
+
+  describe('Dual Seeded PRNG State Isolation', () => {
+    it('results in identical treatment assignments when changing subject ID mask from sequential to random', () => {
+      const configSequential: RandomizationConfig = {
+        ...BASE_CONFIG,
+        subjectIdMask: '{SITE}-{SEQ:4}'
+      };
+
+      const configRandom: RandomizationConfig = {
+        ...BASE_CONFIG,
+        subjectIdMask: '{SITE}-{RND:6}'
+      };
+
+      const resultSequential = generateRandomizationSchema(configSequential);
+      const resultRandom = generateRandomizationSchema(configRandom);
+
+      // Verify subject IDs are indeed different
+      expect(resultSequential.schema.map(r => r.subjectId)).not.toEqual(resultRandom.schema.map(r => r.subjectId));
+
+      // Verify treatment assignments are completely identical
+      expect(resultSequential.schema.map(r => r.treatmentArmId)).toEqual(resultRandom.schema.map(r => r.treatmentArmId));
+    });
+  });
 });
 

src/app/domain/randomization-engine/core/randomization-algorithm.ts

@@ -135,7 +135,8 @@ function generateStandard(
   totalRatio: number,
   schema: GeneratedSchema[],
   usedSubjectIds: Set<string>,
-  registry: SubjectRegistry
+  registry: SubjectRegistry,
+  rngId: () => number
 ): void {
   const stateMap = new Map<string, { blockNumber: number; blockState: any; rule: any }>();
   const siteSubjectCounts = new Map<string, number>();
@@ -177,7 +178,7 @@ function generateStandard(
             resolvedConfig.subjectIdMask,
             { site, stratumCode, sequence: siteSubjectCounts.get(site)! },
             usedSubjectIds,
-            rng
+            rngId
           );
 
           schema.push({ subjectId, site, stratum, stratumCode, blockNumber: state.blockNumber, blockSize, treatmentArm: arm.name, treatmentArmId: arm.id });
@@ -209,7 +210,8 @@ function generateMarginalOnly(
   totalRatio: number,
   schema: GeneratedSchema[],
   usedSubjectIds: Set<string>,
-  registry: SubjectRegistry
+  registry: SubjectRegistry,
+  rngId: () => number
 ): void {
   for (const site of resolvedConfig.sites) {
     let siteSubjectCount = 0;
@@ -249,7 +251,7 @@ function generateMarginalOnly(
           resolvedConfig.subjectIdMask,
           { site, stratumCode, sequence: siteSubjectCount },
           usedSubjectIds,
-          rng
+          rngId
         );
 
         schema.push({
@@ -298,9 +300,15 @@ export function generateRandomizationSchema(
     ? config
     : { ...config, seed: generateCryptoSeed() };
 
-  const mt = new MT19937Internal(MT19937Internal.get31BitSeed(resolvedConfig.seed));
+  const primarySeed = resolvedConfig.seed;
+  const secondarySeed = primarySeed + '-id';
+
+  const mt = new MT19937Internal(MT19937Internal.get31BitSeed(primarySeed));
   const rng = () => mt.random();
 
+  const mtSecondary = new MT19937Internal(MT19937Internal.get31BitSeed(secondarySeed));
+  const rngId = () => mtSecondary.random();
+
   // Generate all strata combinations
   let strataCombinations: Record<string, string>[] = [{}];
   for (const factor of resolvedConfig.strata) {
@@ -355,12 +363,12 @@ export function generateRandomizationSchema(
   const usedSubjectIds = new Set<string>();
 
   if (internalConfig.randomizationMethod === 'MINIMIZATION') {
-    schema.push(...generateMinimization(internalConfig, rng, registry, siteWeights));
+    schema.push(...generateMinimization(internalConfig, rng, registry, siteWeights, rngId));
   } else if (internalConfig.capStrategy === 'MARGINAL_ONLY') {
-    generateMarginalOnly(internalConfig, rng, strataCombinations, totalRatio, schema, usedSubjectIds, registry);
+    generateMarginalOnly(internalConfig, rng, strataCombinations, totalRatio, schema, usedSubjectIds, registry, rngId);
   } else {
     // Both 'MANUAL_MATRIX' (default) and 'PROPORTIONAL' use intersection caps.
-    generateStandard(internalConfig, rng, strataCombinations, totalRatio, schema, usedSubjectIds, registry);
+    generateStandard(internalConfig, rng, strataCombinations, totalRatio, schema, usedSubjectIds, registry, rngId);
   }
 
   return {

src/app/domain/schema-management/services/generation/base.strategy.ts

@@ -90,12 +90,16 @@ export class BaseOrchestrator implements CodeGenerationStrategy {
     const dateStr = DateUtil.getIsoTimestamp();
     const algorithm = method === 'MINIMIZATION' ? 'Pocock-Simon Minimization' : 'PRNG Algorithm: MT19937';
 
+    const secondarySeed = resolvedConfig.seed + '-id';
+    const seedHashSecondary = MT19937Internal.get31BitSeed(secondarySeed);
+
     const data: Record<string, string | number> = {
       protocolId: config.protocolId,
       appVersion: APP_VERSION,
       dateStr,
       algorithm,
       seedHash: ir.seedHash,
+      seedHashSecondary: seedHashSecondary,
       validationVector: valVec.join(', '),
       validationVectorSpace: valVec.join(' '),
       precisionScale: PRECISION_SCALE,

src/app/domain/schema-management/services/generation/ir/templates.ts

@@ -18,6 +18,45 @@ source("mt19937_v1.0.0.r")
 
 init_mt({{seedHash}})
 
+# --- Secondary MT19937 PRNG for Subject ID ---
+mt_state_id <- numeric(624)
+mt_idx_id <- 624
+
+init_mt_id <- function(seed) {
+  mt_state_id[1] <<- seed %% 4294967296
+  for (i in 2:624) {
+    prev <- mt_state_id[i - 1]
+    val <- u32_xor(prev, u32_shr(prev, 30))
+    val <- u32_mul(val, 1812433253) + (i - 1)
+    mt_state_id[i] <<- val %% 4294967296
+  }
+  mt_idx_id <<- 624
+}
+
+random_int_id <- function() {
+  if (mt_idx_id >= 624) {
+    for (kk in 1:624) {
+      y <- u32_or(u32_and(mt_state_id[kk], 2147483648), u32_and(mt_state_id[(kk %% 624) + 1], 2147483647))
+      nxt <- mt_state_id[((kk + 396) %% 624) + 1]
+      mt_state_id[kk] <<- u32_xor(nxt, u32_shr(y, 1))
+      if ((y %% 2) != 0) mt_state_id[kk] <<- u32_xor(mt_state_id[kk], 2567483615)
+    }
+    mt_idx_id <<- 0
+  }
+
+  y <- mt_state_id[mt_idx_id + 1]
+  mt_idx_id <<- mt_idx_id + 1
+
+  y <- u32_xor(y, u32_shr(y, 11))
+  y <- u32_xor(y, u32_and(u32_shl(y, 7), 2636928640))
+  y <- u32_xor(y, u32_and(u32_shl(y, 15), 4022730752))
+  y <- u32_xor(y, u32_shr(y, 18))
+
+  return(y)
+}
+
+init_mt_id({{seedHashSecondary}})
+
 # --- SINGLE-SOURCE TRANSPILED LOGIC ---
 {{minimizationParam}}
 schema_list <- list()
@@ -36,6 +75,7 @@ export const SAS_TEMPLATE = `
 /* Generated At: {{dateStr}} */
 /* Algorithm: {{algorithm}} */
 %let seed = {{seedHash}};
+%let seed_id = {{seedHashSecondary}};
 %let arms = {{arms}};
 %let arms_names = {{armsNames}};
 %let strata_factors = {{strataFactors}};
@@ -59,6 +99,21 @@ data RandomizationSchema;
   /* --- MT19937 PRNG --- */
   %mt19937_init(&seed);
 
+  array mt_id[0:623] _temporary_;
+  mti_id = 624;
+
+  mt_id[0] = &seed_id;
+  do i = 1 to 623;
+    prev_id = mt_id[i-1];
+    val_id = mod(bxor(prev_id, brshift(prev_id, 30)), 4294967296);
+    if val_id < 0 then val_id = val_id + 4294967296;
+    a = 1812433253;
+    a_hi = int(a / 65536); a_lo = mod(a, 65536);
+    b_hi = int(val_id / 65536); b_lo = mod(val_id, 65536);
+    prod_id = mod(mod(a_hi * b_lo + a_lo * b_hi, 65536) * 65536 + a_lo * b_lo, 4294967296);
+    mt_id[i] = mod(prod_id + i, 4294967296);
+  end;
+
   /* --- RUNTIME PARITY VALIDATION --- */
   array val_vec[100] _temporary_ ({{validationVectorSpace}});
   do v_idx = 1 to 100;
@@ -76,6 +131,42 @@ data RandomizationSchema;
 
   /* MT19937 Generator Macro-Equivalent */
   %mt19937_label();
+
+  get_rand_int_id:
+    if mti_id >= 624 then do;
+      do kk = 0 to 226;
+        y_id = mod(bor(band(mt_id[kk], 2147483648), band(mt_id[kk+1], 2147483647)), 4294967296);
+        if y_id < 0 then y_id = y_id + 4294967296;
+        mt_id[kk] = mod(bxor(bxor(mt_id[kk+397], brshift(y_id, 1)), ifn(band(y_id, 1), 2567483615, 0)), 4294967296);
+        if mt_id[kk] < 0 then mt_id[kk] = mt_id[kk] + 4294967296;
+      end;
+      do kk = 227 to 622;
+        y_id = mod(bor(band(mt_id[kk], 2147483648), band(mt_id[kk+1], 2147483647)), 4294967296);
+        if y_id < 0 then y_id = y_id + 4294967296;
+        mt_id[kk] = mod(bxor(bxor(mt_id[kk-227], brshift(y_id, 1)), ifn(band(y_id, 1), 2567483615, 0)), 4294967296);
+        if mt_id[kk] < 0 then mt_id[kk] = mt_id[kk] + 4294967296;
+      end;
+      y_id = mod(bor(band(mt_id[623], 2147483648), band(mt_id[0], 2147483647)), 4294967296);
+      if y_id < 0 then y_id = y_id + 4294967296;
+      mt_id[623] = mod(bxor(bxor(mt_id[396], brshift(y_id, 1)), ifn(band(y_id, 1), 2567483615, 0)), 4294967296);
+      if mt_id[623] < 0 then mt_id[623] = mt_id[623] + 4294967296;
+      mti_id = 0;
+    end;
+
+    y_id = mt_id[mti_id];
+    mti_id = mti_id + 1;
+
+    y_id = mod(bxor(y_id, brshift(y_id, 11)), 4294967296);
+    if y_id < 0 then y_id = y_id + 4294967296;
+    y_id = mod(bxor(y_id, band(blshift(y_id, 7), 2636928640)), 4294967296);
+    if y_id < 0 then y_id = y_id + 4294967296;
+    y_id = mod(bxor(y_id, band(blshift(y_id, 15), 4022730752)), 4294967296);
+    if y_id < 0 then y_id = y_id + 4294967296;
+    y_id = mod(bxor(y_id, brshift(y_id, 18)), 4294967296);
+    if y_id < 0 then y_id = y_id + 4294967296;
+
+    rand_int_id = y_id;
+  return;
 run;
 `;
 
@@ -126,6 +217,7 @@ class MT19937:
         return y & 0xffffffff
 
 rng = MT19937({{seedHash}})
+rng_id = MT19937({{seedHashSecondary}})
 
 # Arms: {{arms}}
 # Ratios: {{ratios}}
@@ -191,7 +283,73 @@ do "mt19937_v1.0.0.do"
 
 mata:
 
+real rowvector mt_state_id
+real scalar mt_idx_id
+
+void init_mt_id(real scalar seed) {
+    mt_state_id = J(1, 624, 0)
+    mt_state_id[1] = seed
+    for (i=2; i<=624; i++) {
+        prev = mt_state_id[i-1]
+        val = mod(bitxor(prev, bitrshift(prev, 30)), 4294967296)
+        if (val < 0) val = val + 4294967296
+
+        a = 1812433253
+        a_hi = trunc(a / 65536)
+        a_lo = mod(a, 65536)
+        b_hi = trunc(val / 65536)
+        b_lo = mod(val, 65536)
+        prod = mod(mod(a_hi * b_lo + a_lo * b_hi, 65536) * 65536 + a_lo * b_lo, 4294967296)
+
+        mt_state_id[i] = mod(prod + (i-1), 4294967296)
+    }
+    mt_idx_id = 624
+}
+
+real scalar random_int_id() {
+    if (mt_idx_id >= 624) {
+        for (kk=1; kk<=227; kk++) {
+            y = mod(bitor(bitand(mt_state_id[kk], 2147483648), bitand(mt_state_id[kk+1], 2147483647)), 4294967296)
+            if (y < 0) y = y + 4294967296
+            mt_state_id[kk] = mod(bitxor(mt_state_id[kk+397], bitrshift(y, 1)), 4294967296)
+            if (mt_state_id[kk] < 0) mt_state_id[kk] = mt_state_id[kk] + 4294967296
+            if (bitand(y, 1) != 0) mt_state_id[kk] = mod(bitxor(mt_state_id[kk], 2567483615), 4294967296)
+            if (mt_state_id[kk] < 0) mt_state_id[kk] = mt_state_id[kk] + 4294967296
+        }
+        for (kk=228; kk<=623; kk++) {
+            y = mod(bitor(bitand(mt_state_id[kk], 2147483648), bitand(mt_state_id[kk+1], 2147483647)), 4294967296)
+            if (y < 0) y = y + 4294967296
+            mt_state_id[kk] = mod(bitxor(mt_state_id[kk-227], bitrshift(y, 1)), 4294967296)
+            if (mt_state_id[kk] < 0) mt_state_id[kk] = mt_state_id[kk] + 4294967296
+            if (bitand(y, 1) != 0) mt_state_id[kk] = mod(bitxor(mt_state_id[kk], 2567483615), 4294967296)
+            if (mt_state_id[kk] < 0) mt_state_id[kk] = mt_state_id[kk] + 4294967296
+        }
+        y = mod(bitor(bitand(mt_state_id[624], 2147483648), bitand(mt_state_id[1], 2147483647)), 4294967296)
+        if (y < 0) y = y + 4294967296
+        mt_state_id[624] = mod(bitxor(mt_state_id[397], bitrshift(y, 1)), 4294967296)
+        if (mt_state_id[624] < 0) mt_state_id[624] = mt_state_id[624] + 4294967296
+        if (bitand(y, 1) != 0) mt_state_id[624] = mod(bitxor(mt_state_id[624], 2567483615), 4294967296)
+        if (mt_state_id[624] < 0) mt_state_id[624] = mt_state_id[624] + 4294967296
+        mt_idx_id = 0
+    }
+
+    y = mt_state_id[mt_idx_id+1]
+    mt_idx_id = mt_idx_id + 1
+
+    y = mod(bitxor(y, bitrshift(y, 11)), 4294967296)
+    if (y < 0) y = y + 4294967296
+    y = mod(bitxor(y, bitand(bitlshift(y, 7), 2636928640)), 4294967296)
+    if (y < 0) y = y + 4294967296
+    y = mod(bitxor(y, bitand(bitlshift(y, 15), 4022730752)), 4294967296)
+    if (y < 0) y = y + 4294967296
+    y = mod(bitxor(y, bitrshift(y, 18)), 4294967296)
+    if (y < 0) y = y + 4294967296
+
+    return(mod(y, 4294967296))
+}
+
 init_mt({{seedHash}})
+init_mt_id({{seedHashSecondary}})
 
 // --- RUNTIME PARITY VALIDATION ---
 real rowvector val_vec

src/app/domain/schema-management/services/generation/ir/transpiler.ts

@@ -265,7 +265,7 @@ export class CodeTranspiler {
          } else if (token.type === 'seq') {
            baseBuilder += `sprintf("%0${token.length}d", ${seqVar}), `;
          } else if (token.type === 'rnd') {
-           baseBuilder += `paste0(ALPHANUMERIC[floor((random_int() / 4294967296) * 36) + 1][1:${token.length}], collapse=""), `;
+           baseBuilder += `paste0(ALPHANUMERIC[floor((random_int_id() / 4294967296) * 36) + 1][1:${token.length}], collapse=""), `;
          } else if (token.type === 'checksum') {
            hasChecksum = true;
            baseBuilder += `"{CHECKSUM}", `;
@@ -308,7 +308,7 @@ export class CodeTranspiler {
          } else if (token.type === 'seq') {
            baseBuilder += `str(${seqVar}).zfill(${token.length}) + `;
          } else if (token.type === 'rnd') {
-           baseBuilder += `''.join(ALPHANUMERIC[int((rng.random_int() / 4294967296) * 36)] for _ in range(${token.length})) + `;
+           baseBuilder += `''.join(ALPHANUMERIC[int((rng_id.random_int() / 4294967296) * 36)] for _ in range(${token.length})) + `;
          } else if (token.type === 'checksum') {
            hasChecksum = true;
            baseBuilder += `"{CHECKSUM}" + `;
@@ -352,8 +352,8 @@ export class CodeTranspiler {
            code += `        length rnd_str_${rndCounter} $ ${token.length};\n`;
            code += `        rnd_str_${rndCounter} = "";\n`;
            code += `        do _k = 1 to ${token.length};\n`;
-           code += `          link get_rand_int;\n`;
-           code += `          char_idx = int((rand_int / 4294967296) * 36) + 1;\n`;
+           code += `          link get_rand_int_id;\n`;
+           code += `          char_idx = int((rand_int_id / 4294967296) * 36) + 1;\n`;
            code += `          rnd_str_${rndCounter} = trim(rnd_str_${rndCounter}) || substr(ALPHANUMERIC, char_idx, 1);\n`;
            code += `        end;\n`;
            baseBuilder += `trim(rnd_str_${rndCounter}) || `;

src/app/domain/schema-management/services/generation/stata.strategy.ts

@@ -76,7 +76,7 @@ export const STATA_CONFIG: LanguageConfig = {
       utils += `string scalar stata_rnd_str(real scalar len) {\n`;
       utils += `    string scalar res; res = "";\n`;
       utils += `    real scalar k;\n`;
-      utils += `    for (k=1; k<=len; k++) { res = res + substr("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789", trunc((random_int() / 4294967296) * 36) + 1, 1); }\n`;
+      utils += `    for (k=1; k<=len; k++) { res = res + substr("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789", trunc((random_int_id() / 4294967296) * 36) + 1, 1); }\n`;
       utils += `    return(res);\n`;
       utils += `}\n\n`;