From cea35eadb009352d8b58b021193e2ad77943f699 Mon Sep 17 00:00:00 2001
From: Walter Oggioni <oggioni.walter@gmail.com>
Date: Sat, 20 May 2023 20:12:43 +0800
Subject: [PATCH] made vector iterable

---
 .../main/java/net/woggioni/jmath/Matrix.java  | 35 ++++++++++-
 .../java/net/woggioni/jmath/Rational.java     |  7 ++-
 .../main/java/net/woggioni/jmath/Vector.java  | 59 ++++++++++++++++++-
 3 files changed, 98 insertions(+), 3 deletions(-)

diff --git a/jmath/src/main/java/net/woggioni/jmath/Matrix.java b/jmath/src/main/java/net/woggioni/jmath/Matrix.java
index dbdfccf..f803d3a 100644
--- a/jmath/src/main/java/net/woggioni/jmath/Matrix.java
+++ b/jmath/src/main/java/net/woggioni/jmath/Matrix.java
@@ -1,17 +1,19 @@
 package net.woggioni.jmath;
 
+import lombok.Data;
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 import lombok.Setter;
 import lombok.SneakyThrows;
 
+import java.util.Iterator;
 import java.util.Objects;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
 import static net.woggioni.jwo.Requirement.require;
 
-public class Matrix<T extends NumericType<T>> {
+public class Matrix<T extends NumericType<T>> implements Iterable<Matrix.Element<T>> {
 
     public interface Pivot {
         <U extends NumericType<U>> Matrix<U> mul(Matrix<U> m);
@@ -558,4 +560,35 @@ public class Matrix<T extends NumericType<T>> {
     public T norm2() {
         return squaredNorm2().sqrt();
     }
+
+    @Override
+    public Iterator<Element<T>> iterator() {
+        return new Iterator<>() {
+            int i = 0;
+            int j = 0;
+
+            @Override
+            public boolean hasNext() {
+                return i * getColumns() + j < getRows() * getColumns();
+            }
+
+            @Override
+            public Element<T> next() {
+                Element<T> result = new Element<>(i, j, get(i, j));
+                ++j;
+                if (j == getColumns()) {
+                    j = 0;
+                    ++i;
+                }
+                return result;
+            }
+        };
+    }
+
+    @Data
+    public static class Element<T> {
+        private final int row;
+        private final int column;
+        private final T value;
+    }
 }
diff --git a/jmath/src/main/java/net/woggioni/jmath/Rational.java b/jmath/src/main/java/net/woggioni/jmath/Rational.java
index a76c269..124b14e 100644
--- a/jmath/src/main/java/net/woggioni/jmath/Rational.java
+++ b/jmath/src/main/java/net/woggioni/jmath/Rational.java
@@ -68,7 +68,12 @@ public class Rational implements NumericType<Rational> {
     public static Rational of(long n) {
         return new Rational(n, 1);
     }
-
+    public static Rational of(BigInteger num) {
+        return new Rational(num, BigInteger.ONE);
+    }
+    public static Rational of(BigInteger num, BigInteger den) {
+        return new Rational(num, den);
+    }
     private Rational simplify() {
         BigInteger gcd = BigIntegerExt.gcd(num.abs(), den.abs());
         num = num.divide(gcd);
diff --git a/jmath/src/main/java/net/woggioni/jmath/Vector.java b/jmath/src/main/java/net/woggioni/jmath/Vector.java
index 32045c2..8d1f1d1 100644
--- a/jmath/src/main/java/net/woggioni/jmath/Vector.java
+++ b/jmath/src/main/java/net/woggioni/jmath/Vector.java
@@ -1,15 +1,19 @@
 package net.woggioni.jmath;
 
 import lombok.AccessLevel;
+import lombok.Data;
 import lombok.RequiredArgsConstructor;
 
+import java.util.Iterator;
 import java.util.Objects;
+import java.util.function.BiFunction;
+import java.util.function.Function;
 import java.util.function.IntFunction;
 
 import static net.woggioni.jwo.Requirement.require;
 
 @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
-public class Vector<T extends NumericType<T>> {
+public class Vector<T extends NumericType<T>> implements Iterable<Vector.Element<T>> {
     private final NumericTypeFactory<T> numericTypeFactory;
     private final T[] values;
 
@@ -39,6 +43,35 @@ public class Vector<T extends NumericType<T>> {
         require(() -> other.size() == size()).otherwise(SizeException.class, "Vectors must be of same size");
     }
 
+    public Vector<T> map(Vector<T> other, BiFunction<T, T, T> op) {
+        requireSameSize(other);
+        return of(numericTypeFactory, size(), (i) -> op.apply(get(i), other.get(i)));
+    }
+
+    public <U extends NumericType<U>> Vector<U> map(NumericTypeFactory<U> numericTypeFactory, Function<T, U> op) {
+        return of(numericTypeFactory, size(), (i) -> op.apply(get(i)));
+    }
+
+    public Vector<T> map(Function<T, T> op) {
+        return of(numericTypeFactory, size(), (i) -> op.apply(get(i)));
+    }
+
+    public Vector<T> sum(T f) {
+        return new Vector<>(numericTypeFactory, size(), index -> get(index).add(f));
+    }
+
+    public Vector<T> sub(T f) {
+        return new Vector<>(numericTypeFactory, size(), index -> get(index).sub(f));
+    }
+
+    public Vector<T> div(T f) {
+        return new Vector<>(numericTypeFactory, size(), index -> get(index).div(f));
+    }
+
+    public Vector<T> mul(T f) {
+        return new Vector<>(numericTypeFactory, size(), index -> get(index).mul(f));
+    }
+
     public Vector<T> sum(Vector<T> other) {
         requireSameSize(other);
         return new Vector<>(numericTypeFactory, size(), index -> get(index).add(other.get(index)));
@@ -126,6 +159,24 @@ public class Vector<T extends NumericType<T>> {
         return sb.toString();
     }
 
+    @Override
+    public Iterator<Element<T>> iterator() {
+        return new Iterator<Element<T>>() {
+            private int i = 0;
+            @Override
+            public boolean hasNext() {
+                return i < size();
+            }
+
+            @Override
+            public Element<T> next() {
+                Element<T> result = new Element<>(i, get(i));
+                i++;
+                return  result;
+            }
+        };
+    }
+
     public static <T extends NumericType<T>> Vector<T> of(NumericTypeFactory<T> numericTypeFactory, T... values) {
         return new Vector<>(numericTypeFactory, values);
     }
@@ -139,4 +190,10 @@ public class Vector<T extends NumericType<T>> {
                                                           IntFunction<T> generator) {
         return new Vector<>(numericTypeFactory, size, generator);
     }
+
+    @Data
+    public static class Element<T> {
+        private final int index;
+        private final T value;
+    }
 }