Add bit-math.hpp

src/game/genetics/bit-math.hpp

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2020  Christopher J. Howard
+ *
+ * This file is part of Antkeeper source code.
+ *
+ * Antkeeper source code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Antkeeper source code is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef ANTKEEPER_BIT_MATH_HPP
+#define ANTKEEPER_BIT_MATH_HPP
+
+namespace dna
+{
+
+/**
+ * Reads bits from the least significant bits of a value and returns them in the positions marked by a mask.
+ *
+ * @param x Value from which bits should be read.
+ * @param mask Bit mask indicating where bits should be deposited.
+ * @return Bits from the least significant bits of @p x in the positions marked by @p mask.
+ */
+template <class T>
+constexpr T bit_deposit(T x, T mask) noexcept;
+
+/**
+ * Reads bits from a value in the positions marked by a mask and returns them in the least significant bits.
+ *
+ * @param x Value from which bits should be read.
+ * @param mask Bit mask indicating which bits to extract.
+ * @return Bits of @p x from the positions marked by @p mask in the least significant bits.
+ */
+template <class T>
+constexpr T bit_extract(T x, T mask) noexcept;
+
+/**
+ * Returns the number of set bits in a value, known as a *population count* or *Hamming weight*.
+ *
+ * @param x Value to count.
+ * @return Number of set bits in @p x.
+ */
+template <typename T>
+constexpr int popcount(T x) noexcept;
+
+template <class T>
+constexpr T bit_deposit(T x, T mask) noexcept
+{
+	T result = 0;
+	
+	for (T i = 1; mask; i <<= 1)
+	{
+		if (x & i)
+			result |= mask & -mask;
+		mask &= mask - 1;
+	}
+	
+	return result;
+}
+
+template <class T>
+constexpr T bit_extract(T x, T mask) noexcept
+{
+	T result = 0;
+	
+	for (T i = 1; mask; i <<= 1)
+	{
+		if (x & mask & -mask)
+			result |= i;
+		mask &= mask - 1;
+	}
+	
+	return result;
+}
+
+template <typename T>
+constexpr int popcount(T x) noexcept
+{
+	int n = 0;
+	for (; x; ++n)
+		x &= x - 1;
+	return n;
+}
+
+} // namespace dna
+
+#endif // ANTKEEPER_BIT_MATH_HPP

src/game/genetics/genetic-operators.hpp → src/game/genetics/crossover.hpp

@@ -17,19 +17,19 @@
  * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef ANTKEEPER_GENETIC_OPERATORS_HPP
-#define ANTKEEPER_GENETIC_OPERATORS_HPP
+#ifndef ANTKEEPER_CROSSOVER_HPP
+#define ANTKEEPER_CROSSOVER_HPP
 
 namespace dna
 {
 
 /**
- * Performs a genetic crossover on two blocks of interleaved alleles.
+ * Performs a genetic crossover between two chromosomes.
  *
- * @param a Interleaved allele block of the first parent.
- * @param b Interleaved allele block of the second parent.
+ * @param a Chromosome of the first parent.
+ * @param b Chromosome of the second parent.
  * @param g Uniform random bit generator.
- * @return Interleaved allele block of the new offspring.
+ * @return Chromosome of the new offspring.
  */
 template <class T, class URBG>
 T crossover(T a, T b, URBG&& g)
@@ -48,19 +48,6 @@ T crossover(T a, T b, URBG&& g)
 	return c;
 }
 
-/**
- * Mutates a single allele in an interleaved allele block.
- *
- * @param x Interleaved allele block to mutate.
- * @param g Uniform random bit generator.
- * @return Mutated copy of @p x.
- */
-template <class T, class URBG>
-T mutate(T x, URBG&& g)
-{
-	return x ^ (T(1) << (g() % (sizeof(T) << 3)));
-}
-
 } // namespace dna
 
-#endif // ANTKEEPER_GENETIC_OPERATORS_HPP
+#endif // ANTKEEPER_CROSSOVER_HPP

src/game/genetics/gene.hpp

@@ -1,33 +0,0 @@
-/*
- * Copyright (C) 2020  Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper source code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef ANTKEEPER_GENE_HPP
-#define ANTKEEPER_GENE_HPP
-
-#include <cstdint>
-
-namespace dna
-{
-
-/// A 2-bit gene with two alleles.
-typedef std::uint8_t gene;
-
-} // namespace dna
-
-#endif // ANTKEEPER_GENE_HPP

src/game/genetics/allele.hpp → src/game/genetics/mutate.hpp

@@ -17,24 +17,25 @@
  * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef ANTKEEPER_ALLELE_HPP
-#define ANTKEEPER_ALLELE_HPP
-
-#include <cstdint>
+#ifndef ANTKEEPER_MUTATE_HPP
+#define ANTKEEPER_MUTATE_HPP
 
 namespace dna
 {
 
-/// Enumerates allele types.
-enum allele: std::uint8_t
+/**
+ * Mutates a value by flipping a single random bit.
+ *
+ * @param x Value to mutate.
+ * @param g Uniform random bit generator.
+ * @return Mutated copy of @p x.
+ */
+template <class T, class URBG>
+T mutate(T x, URBG&& g)
 {
-	/// Indicates an allele is recessive.
-	recessive = 0,
-	
-	/// Indicates an allele is dominant.
-	dominant = 1
-};
+	return x ^ (T(1) << (g() % (sizeof(T) << 3)));
+}
 
 } // namespace dna
 
-#endif // ANTKEEPER_ALLELE_HPP
+#endif // ANTKEEPER_MUTATE_HPP

src/game/genetics/popcount.hpp

@@ -1,41 +0,0 @@
-/*
- * Copyright (C) 2020  Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper source code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef ANTKEEPER_POPCOUNT_HPP
-#define ANTKEEPER_POPCOUNT_HPP
-
-namespace dna
-{
-
-/// Returns the number of set bits (*population count*) in @p x. Also known as the *Hamming weight*.
-template <typename T>
-constexpr int popcount(T x) noexcept;
-
-template <typename T>
-inline constexpr int popcount(T x) noexcept
-{
-	int n;
-	for (n = 0; x; ++n)
-		x &= x - 1;
-	return n;
-}
-
-} // namespace dna
-
-#endif // ANTKEEPER_POPCOUNT_HPP

src/game/genetics/zygosity.hpp

@@ -22,7 +22,7 @@
 
 namespace dna
 {
-	
+
 /**
  * Tests a gene for heterozygosity.
  *
@@ -44,13 +44,13 @@ bool is_homozygous(T x);
 template <class T>
 inline bool is_heterozygous<T>(T x)
 {
-	return x & 1 != (x >> 1) & 1;
+	return (x & 1) != (x >> 1);
 }
 
 template <class T>
 inline bool is_homozygous<T>(T x)
 {
-	return x & 1 == (x >> 1) & 1;
+	return (x & 1) == (x >> 1);
 }
 
 } // namespace dna