Move PermutationElement to math.h (and get rid of shuffle.h)

src/pbrt/util/lowdiscrepancy.cpp

@@ -5,10 +5,10 @@
 #include <pbrt/util/lowdiscrepancy.h>
 
 #include <pbrt/util/bits.h>
+#include <pbrt/util/math.h>
 #include <pbrt/util/parallel.h>
 #include <pbrt/util/primes.h>
 #include <pbrt/util/print.h>
-#include <pbrt/util/shuffle.h>
 #include <pbrt/util/stats.h>
 
 namespace pbrt {

src/pbrt/util/lowdiscrepancy.h

@@ -9,9 +9,9 @@
 
 #include <pbrt/util/check.h>
 #include <pbrt/util/float.h>
+#include <pbrt/util/math.h>
 #include <pbrt/util/primes.h>
 #include <pbrt/util/pstd.h>
-#include <pbrt/util/shuffle.h>
 #include <pbrt/util/sobolmatrices.h>
 #include <pbrt/util/vecmath.h>
 

src/pbrt/util/math.h

@@ -728,6 +728,41 @@ int NextPrime(int x);
 pstd::optional<SquareMatrix<3>> LinearLeastSquares(const Float A[][3], const Float B[][3],
                                                    int rows);
 
+// Permutation Inline Function Declarations
+PBRT_CPU_GPU
+inline int PermutationElement(uint32_t i, uint32_t l, uint32_t p);
+
+PBRT_CPU_GPU
+inline int PermutationElement(uint32_t i, uint32_t l, uint32_t p) {
+    uint32_t w = l - 1;
+    w |= w >> 1;
+    w |= w >> 2;
+    w |= w >> 4;
+    w |= w >> 8;
+    w |= w >> 16;
+    do {
+        i ^= p;
+        i *= 0xe170893d;
+        i ^= p >> 16;
+        i ^= (i & w) >> 4;
+        i ^= p >> 8;
+        i *= 0x0929eb3f;
+        i ^= p >> 23;
+        i ^= (i & w) >> 1;
+        i *= 1 | p >> 27;
+        i *= 0x6935fa69;
+        i ^= (i & w) >> 11;
+        i *= 0x74dcb303;
+        i ^= (i & w) >> 2;
+        i *= 0x9e501cc3;
+        i ^= (i & w) >> 2;
+        i *= 0xc860a3df;
+        i &= w;
+        i ^= i >> 5;
+    } while (i >= l);
+    return (i + p) % l;
+}
+
 PBRT_CPU_GPU
 inline Float ErfInv(Float a) {
 #ifdef PBRT_IS_GPU_CODE

src/pbrt/util/math_test.cpp

@@ -11,7 +11,6 @@
 #include <pbrt/util/float.h>
 #include <pbrt/util/math.h>
 #include <pbrt/util/rng.h>
-#include <pbrt/util/shuffle.h>
 #include <pbrt/util/vecmath.h>
 
 #include <vector>

src/pbrt/util/shuffle.h

-// pbrt is Copyright(c) 1998-2020 Matt Pharr, Wenzel Jakob, and Greg Humphreys.
-// The pbrt source code is licensed under the Apache License, Version 2.0.
-// SPDX: Apache-2.0
-
-#ifndef PBRT_UTIL_SHUFFLE_H
-#define PBRT_UTIL_SHUFFLE_H
-
-#include <pbrt/pbrt.h>
-
-#include <pbrt/util/pstd.h>
-#include <pbrt/util/rng.h>
-
-#include <algorithm>
-#include <cstdint>
-
-namespace pbrt {
-
-// Permutation Inline Function Declarations
-PBRT_CPU_GPU
-inline int PermutationElement(uint32_t i, uint32_t l, uint32_t p);
-
-PBRT_CPU_GPU
-inline int PermutationElement(uint32_t i, uint32_t l, uint32_t p) {
-    uint32_t w = l - 1;
-    w |= w >> 1;
-    w |= w >> 2;
-    w |= w >> 4;
-    w |= w >> 8;
-    w |= w >> 16;
-    do {
-        i ^= p;
-        i *= 0xe170893d;
-        i ^= p >> 16;
-        i ^= (i & w) >> 4;
-        i ^= p >> 8;
-        i *= 0x0929eb3f;
-        i ^= p >> 23;
-        i ^= (i & w) >> 1;
-        i *= 1 | p >> 27;
-        i *= 0x6935fa69;
-        i ^= (i & w) >> 11;
-        i *= 0x74dcb303;
-        i ^= (i & w) >> 2;
-        i *= 0x9e501cc3;
-        i ^= (i & w) >> 2;
-        i *= 0xc860a3df;
-        i &= w;
-        i ^= i >> 5;
-    } while (i >= l);
-    return (i + p) % l;
-}
-
-}  // namespace pbrt
-
-#endif  // PBRT_UTIL_SHUFFLE_H