MatrixBlocks synced with CodeExpert

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/export.json

+{
+  "cxweb": "4.0.5",
+  "cxrun": "2.0.1"
+}

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/MatrixBlocks.hpp

+#ifndef MATRIXBLOCK_HPP
+#define MATRIXBLOCK_HPP
+
+// The purpose of this exercise is introduce block operations on Eigen matrices.
+
+// TO DO: Include the appropriate header files.
+// START
+
+// END
+
+// We can use the Eigen namespace to improve the readability of our code.
+// This allows us to skip the "Eigen::" in "Eigen::MatrixXd" for example.
+// TO DO: Add the following line below: using namespace Eigen;
+// START
+
+// END
+
+/* SAM_LISTING_BEGIN_0 */
+MatrixXd zero_row_col(const MatrixXd &A, int p, int q) {
+  /*
+   * This function takes a matrix A, and returns a matrix that is exactly the
+   * same, except that row p and column q are set to zero.
+   */
+  // Make a copy of A.
+  MatrixXd Anew(A);
+  
+  // TO DO: Set the entries of row number p and column number q to zero.
+  // Hint: We can access rows and columns of A by A.row() and A.col().
+  // The setZero() is useful here. START
+  
+  // END
+
+  return Anew;
+}
+/* SAM_LISTING_END_0 */
+
+/* SAM_LISTING_BEGIN_1 */
+MatrixXd swap_left_right_blocks(const MatrixXd &A, int p) {
+  /*
+   * Writing as a block matrix A = [B C], where B denotes the first p columns of
+   * A, and C denotes the q=(A.cols() - p) last columns, this functions returns
+   * D = [C B].
+   */
+  
+  MatrixXd B, C;
+  
+  // We can use .rows() and .cols() to get the number of rows and columns in A.
+  int q = A.cols() - p;
+
+  // A.block( i, j, m, n ) returns the m by n block that has its top-left corner
+  // at the index (i,j) in A. Hence, the first p columns of A can be accessed in
+  // the following way:
+  B = A.block(0, 0, A.rows(), p);
+
+  // TO DO: Use A.block() to define C as the matrix containing the last q
+  // columns of A. START
+  
+  // END
+  
+  // Make a copy of A.
+  MatrixXd Anew(A);
+  // The block() method can access arbitrary blocks within a matrix.
+  // For our purposes, it is actually simpler to use leftCols() and rightCols().
+  Anew.leftCols(q) = C;
+
+  // TO DO: Use A.rightCols() to fill in the remaining columns of the new matrix
+  // A. START
+  
+  // END
+
+  // Tip: Many more methods exist that are special cases of block(),
+  // e.g. topRows(), bottomRows(), topLeftCorner(), bottomLeftCorner(), ...
+  // For vectors we have head(), tail(), and segment().
+
+  return Anew;
+}
+/* SAM_LISTING_END_1 */
+
+/* SAM_LISTING_BEGIN_2 */
+MatrixXd tridiagonal(int n, double a, double b, double c) {
+  /*
+   * This function creates an n by n tridiagonal matrix with the values
+   *      a on the first subdiagonal,
+   *      b on the diagonal, and
+   *      c on the first superdiagonal.
+   * Example for n=5:
+   *     [ b c 0 0 0 ]
+   *     [ a b c 0 0 ]
+   * A = [ 0 a b c 0 ]
+   *     [ 0 0 a b c ]
+   *     [ 0 0 0 a b ]
+   */
+
+  MatrixXd A;
+
+  // TO DO: Fill the matrix A with zeros. Then fill the subdiagonal with the
+  // value a, the diagonal with b and the superdiagonal with c. Hint: You can
+  // get the diagonal of A by A.diagonal(). Moreover, you can get the super- and
+  // subdiagonals by passing +1 or -1 as arguments to A.diagonal(). START
+  
+  // END
+  return A;
+}
+/* SAM_LISTING_END_2 */
+
+#endif

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/conf.yml

+# Code Expert Generic Project Configuration.
+#
+# In case this file is omitted, the execution is done with the default values.
+
+# You can either define a cmd or a script file to be executed.
+# Default to script file setting a cmd overrides it.
+cmd:
+#  compile: echo "COMPILE"
+#  run: echo "RUN"
+#  test: echo "TEST"
+#  submit: echo "SUBMIT"
+
+# All scripts are set by default to "/scripts/${ACTION}.sh"
+script:
+  compile: /scripts/compile.sh
+  run: /scripts/run.sh
+  test: /scripts/test.sh
+  submit: /scripts/submit.sh
\ No newline at end of file

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/cx_description/conf.yml

+descriptions:
+  default:
+    name: Default
+    default: true
+# Optionally add mulitple versions here.
+# Use the file name without the .md extension as key and add a `name:` to it.
\ No newline at end of file

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/cx_description/default.md

+
+# Tutorial: part 2/3
+## Matrix blocks
+
+
+> Eigen matrices have a range of methods to access their submatrices (blocks), instead of individual entries at a time.Suppose A is an Eigen::MatrixXd object, then a few useful methods are:
+* `A.row(i)`: the i-th row of A,
+* `A.col(j)`: the j-th column of A,
+* `A.topRows(p)`: the first p rows of A,
+* `A.leftCols(q)`: the first q columns of A,
+* `A.bottomRightCorner(p,q)`: the p by q matrix formed by the intersection of the last p rows and last q columns of A, and more generally
+* `A.block(i,j,p,q)`: the p by q submatrix of A, whose top-left corner is at the index (i,j).
+
+
+> The purpose of this exercise is to learn to declare and initialize Eigen matrices, and to get familiar with some handy typedefs and methods.
+
+> Open "MatrixBlocks.hpp" and fill in the missing code in between the delimiters `// START` and `// END` according to the instructions preceded by `// TO DO:`.
+
+> Read each function of the program carefully. The code will not compile until after the first two tasks are finished, which is to include headers and set the namespace.
\ No newline at end of file

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/cx_description/test_doc.md

+
+
+# Tests of MatrixBlocks.hpp
+
+> There are three functions in MatrixBlocks.hpp and main.cpp has one test for each function.
+***
+> `zero_row_col( MatrixXd A, int p, int q )`: This function returns a copy of A with row p and column q set to zero.
+The test prints `zero_row_col(Matrix3d::Constant(-1),0,1)`, and the correct result is:
+```
+ 0  0  0
+-1  0 -1
+-1  0 -1
+```
+***
+> `swap_left_right_blocks( MatrixXd A, int p )`: This function swaps splits the matrix A into two blocks, the first p columns and the rest, and returns a matrix in which these blocks have been swapped.
+The test prints `swap_left_right_blocks(MatrixXd::Identity(4,3),2)`, and the correct result is:
+```
+0 1 0
+0 0 1
+1 0 0
+0 0 0
+```
+***
+> `tridiagonal( int n, double a, double b, double c)`: This function creates an n by n tridiagonal matrix with constant diagonals with the values a, b, and c.
+The test prints `tridiagonal(4,-1,2,-1)`, and the correct result is:
+```
+ 2 -1  0  0
+-1  2 -1  0
+ 0 -1  2 -1
+ 0  0 -1  2
+```

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/main.cpp

+
+
+#include "MatrixBlocks.hpp"
+#include <iostream>
+
+
+int main(){
+    
+    std::cout<< "\nTest of zero_row_col():\n";
+    Matrix3d A = Matrix3d::Constant(-1);
+    std::cout<< zero_row_col( A, 0, 1 ) << "\n\n";
+    
+    std::cout<< "Test of swap_left_right_blocks():\n";
+    MatrixXd B = MatrixXd::Identity( 4, 3 );
+    std::cout<< swap_left_right_blocks( B, 2 ) << "\n\n";
+    
+    std::cout<< "Test of tridiagonal():\n";
+    std::cout<<tridiagonal(4,-1,2,-1)<< "\n\n";
+    return 0;
+    }

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/scripts/compile.sh

+#!/bin/bash
+
+echo "Compiling ..."
+
+
+# compile c code
+# find . -iname '*.cpp' | sort | xargs g++ -fdiagnostics-color=always --pedantic -Wextra -Wall -std=c++14  -I/usr/include/python3.7m -llibpython  -o bin/a.out || exit 1
+
+# Compiling for 'matplotlibcpp.h'
+mkdir -p bin
+
+find . -iname '*.cpp' | sort | xargs \
+  g++ -fdiagnostics-color=always -std=c++11 \
+  -I/usr/local/include/python3.7m \
+  -I/usr/local/lib/python3.7/site-packages/numpy/core/include \
+  -I/usr/include/eigen3/ \
+  -lpython3.7m \
+  -lpthread -lutil -ldl \
+  -Xlinker -export-dynamic \
+  -o bin/a.out
+
+
+echo "Compilation successful"
\ No newline at end of file

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/scripts/run.sh

+#!/bin/bash
+
+export PYTHONIOENCODING="UTF-8"
+
+# compile (call compile script)
+bash "${WORKDIR}/scripts/compile.sh"
+
+# run
+bin/a.out 
\ No newline at end of file

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/scripts/submit.sh

+#!/bin/bash
+
+echo "Not implemented"
\ No newline at end of file

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/scripts/test.sh

+#!/bin/bash
+
+# run (call run script)
+bash "${WORKDIR}/scripts/run.sh"
\ No newline at end of file

Assignments/Codes/Introduction/MatrixBlocks/CodeExpert/template/tests.csv

+// "testname", "input", "expected output", "points", "execution time limit (ms)"
+"zero_row_col", "(any input)", " 0  0  0\n-1  0 -1\n-1  0 -1",  "1", "5000",
+"swap_left_right_blocks", "(any input)", "0 1 0\n0 0 1\n1 0 0\n0 0 0",  "1", "5000",
+"tridiagonal", "(any input)", " 2 -1  0  0\n-1  2 -1  0\n 0 -1  2 -1\n 0  0 -1  2",  "1", "5000",