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Commit7abd239

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caos321xzero
and
xzero
authored
Add MatrixUtil for matrix operations (TheAlgorithms#2798)
Co-authored-by: xzero <andrejmezler@yahoo.de>
1 parent5b261e9 commit7abd239

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‎Maths/MatrixUtil.java

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packageMaths;
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importjava.math.BigDecimal;
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importjava.util.Arrays;
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importjava.util.Objects;
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importjava.util.Optional;
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importjava.util.function.BiFunction;
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importjava.util.stream.IntStream;
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/**
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* @author: caos321
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* @date: 31 October 2021 (Sunday)
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*/
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publicclassMatrixUtil {
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publicstaticbooleanisValid(finalBigDecimal[][]matrix) {
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returnmatrix !=null &&matrix.length >0 &&matrix[0].length >0;
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}
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publicstaticbooleanhasEqualSizes(finalBigDecimal[][]matrix1,finalBigDecimal[][]matrix2) {
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returnisValid(matrix1) &&isValid(matrix2)
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&&matrix1.length ==matrix2.length
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&&matrix1[0].length ==matrix2[0].length;
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}
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publicstaticbooleancanMultiply(finalBigDecimal[][]matrix1,finalBigDecimal[][]matrix2) {
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returnisValid(matrix1) &&isValid(matrix2)
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&&matrix1[0].length ==matrix2.length;
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}
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publicstaticOptional<BigDecimal[][]>operate(finalBigDecimal[][]matrix1,
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finalBigDecimal[][]matrix2,
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finalBiFunction<BigDecimal,BigDecimal,BigDecimal>operation) {
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if (!hasEqualSizes(matrix1,matrix2)) {
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returnOptional.empty();
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}
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finalintrowSize =matrix1.length;
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finalintcolumnSize =matrix1[0].length;
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finalBigDecimal[][]result =newBigDecimal[rowSize][columnSize];
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IntStream.range(0,rowSize).forEach(rowIndex ->
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IntStream.range(0,columnSize).forEach(columnIndex -> {
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finalBigDecimalvalue1 =matrix1[rowIndex][columnIndex];
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finalBigDecimalvalue2 =matrix2[rowIndex][columnIndex];
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result[rowIndex][columnIndex] =operation.apply(value1,value2);
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}));
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returnOptional.of(result);
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}
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publicstaticOptional<BigDecimal[][]>add(finalBigDecimal[][]matrix1,finalBigDecimal[][]matrix2) {
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returnoperate(matrix1,matrix2,BigDecimal::add);
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}
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publicstaticOptional<BigDecimal[][]>subtract(finalBigDecimal[][]matrix1,finalBigDecimal[][]matrix2) {
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returnoperate(matrix1,matrix2,BigDecimal::subtract);
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}
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publicstaticOptional<BigDecimal[][]>multiply(finalBigDecimal[][]matrix1,finalBigDecimal[][]matrix2) {
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if (!canMultiply(matrix1,matrix2)) {
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returnOptional.empty();
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}
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finalintsize =matrix1[0].length;
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finalintmatrix1RowSize =matrix1.length;
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finalintmatrix2ColumnSize =matrix2[0].length;
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finalBigDecimal[][]result =newBigDecimal[matrix1RowSize][matrix2ColumnSize];
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IntStream.range(0,matrix1RowSize).forEach(rowIndex ->
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IntStream.range(0,matrix2ColumnSize).forEach(columnIndex ->
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result[rowIndex][columnIndex] =IntStream.range(0,size).mapToObj(index -> {
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finalBigDecimalvalue1 =matrix1[rowIndex][index];
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finalBigDecimalvalue2 =matrix2[index][columnIndex];
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returnvalue1.multiply(value2);
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})
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.reduce(BigDecimal.ZERO,BigDecimal::add)
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)
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);
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returnOptional.of(result);
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}
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publicstaticvoidassertThat(finalBigDecimal[][]actual,finalBigDecimal[][]expected) {
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if (!Objects.deepEquals(actual,expected)) {
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thrownewAssertionError(String.format(
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"expected=%s but was actual=%s",
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Arrays.deepToString(expected),
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Arrays.deepToString(actual)
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));
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}
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}
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publicstaticvoidmain(finalString[]args) {
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{
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finalBigDecimal[][]matrix1 = {
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{newBigDecimal(3),newBigDecimal(2)},
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{newBigDecimal(0),newBigDecimal(1)},
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};
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finalBigDecimal[][]matrix2 = {
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{newBigDecimal(1),newBigDecimal(3)},
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{newBigDecimal(2),newBigDecimal(0)},
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};
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finalBigDecimal[][]actual =add(matrix1,matrix2)
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.orElseThrow(() ->newAssertionError("Could not compute matrix!"));
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finalBigDecimal[][]expected = {
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{newBigDecimal(4),newBigDecimal(5)},
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{newBigDecimal(2),newBigDecimal(1)}
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};
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assertThat(actual,expected);
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}
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{
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finalBigDecimal[][]matrix1 = {
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{newBigDecimal(1),newBigDecimal(4)},
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{newBigDecimal(5),newBigDecimal(6)},
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};
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finalBigDecimal[][]matrix2 = {
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{newBigDecimal(2),newBigDecimal(0)},
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{newBigDecimal(-2),newBigDecimal(-3)},
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};
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finalBigDecimal[][]actual =subtract(matrix1,matrix2)
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.orElseThrow(() ->newAssertionError("Could not compute matrix!"));
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finalBigDecimal[][]expected = {
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{newBigDecimal(-1),newBigDecimal(4)},
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{newBigDecimal(7),newBigDecimal(9)}
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};
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assertThat(actual,expected);
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}
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{
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finalBigDecimal[][]matrix1 = {
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{newBigDecimal(1),newBigDecimal(2),newBigDecimal(3)},
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{newBigDecimal(4),newBigDecimal(5),newBigDecimal(6)},
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{newBigDecimal(7),newBigDecimal(8),newBigDecimal(9)}
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};
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finalBigDecimal[][]matrix2 = {
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{newBigDecimal(1),newBigDecimal(2)},
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{newBigDecimal(3),newBigDecimal(4)},
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{newBigDecimal(5),newBigDecimal(6)}
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};
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finalBigDecimal[][]actual =multiply(matrix1,matrix2)
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.orElseThrow(() ->newAssertionError("Could not compute matrix!"));
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finalBigDecimal[][]expected = {
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{newBigDecimal(22),newBigDecimal(28)},
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{newBigDecimal(49),newBigDecimal(64)},
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{newBigDecimal(76),newBigDecimal(100)}
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};
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assertThat(actual,expected);
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}
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}
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}

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