Rewrite tutorial section on solving linear systems

6 files changed, 52 insertions, 0 deletions

diff --git a/doc/snippets/Tutorial_solve_matrix_inverse.cpp b/doc/snippets/Tutorial_solve_matrix_inverse.cpp
new file mode 100644
index 000000000..fff324446
--- /dev/null
+++ b/doc/snippets/Tutorial_solve_matrix_inverse.cpp
@@ -0,0 +1,6 @@
+Matrix3f A;
+Vector3f b;
+A << 1,2,3,  4,5,6,  7,8,10;
+b << 3, 3, 4;
+Vector3f x = A.inverse() * b;
+cout << "The solution is:" << endl << x << endl;
diff --git a/doc/snippets/Tutorial_solve_multiple_rhs.cpp b/doc/snippets/Tutorial_solve_multiple_rhs.cpp
new file mode 100644
index 000000000..fbb15165a
--- /dev/null
+++ b/doc/snippets/Tutorial_solve_multiple_rhs.cpp
@@ -0,0 +1,10 @@
+Matrix3f A(3,3);
+A << 1,2,3,  4,5,6,  7,8,10;
+Matrix<float,3,2> B;
+B << 3,1, 3,1, 4,1;
+Matrix<float,3,2> X;
+A.partialLu().solve(B, &X);
+cout << "The solution with right-hand side (3,3,4) is:" << endl;
+cout << X.col(0) << endl;
+cout << "The solution with right-hand side (1,1,1) is:" << endl;
+cout << X.col(1) << endl;
diff --git a/doc/snippets/Tutorial_solve_reuse_decomposition.cpp b/doc/snippets/Tutorial_solve_reuse_decomposition.cpp
new file mode 100644
index 000000000..b4112adc4
--- /dev/null
+++ b/doc/snippets/Tutorial_solve_reuse_decomposition.cpp
@@ -0,0 +1,13 @@
+Matrix3f A(3,3);
+A << 1,2,3,  4,5,6,  7,8,10;
+PartialLU<Matrix3f> luOfA(A); // compute LU decomposition of A
+Vector3f b;
+b << 3,3,4;
+Vector3f x;
+luOfA.solve(b, &x);
+cout << "The solution with right-hand side (3,3,4) is:" << endl;
+cout << x << endl;
+b << 1,1,1;
+luOfA.solve(b, &x);
+cout << "The solution with right-hand side (1,1,1) is:" << endl;
+cout << x << endl;
diff --git a/doc/snippets/Tutorial_solve_singular.cpp b/doc/snippets/Tutorial_solve_singular.cpp
new file mode 100644
index 000000000..da94ad445
--- /dev/null
+++ b/doc/snippets/Tutorial_solve_singular.cpp
@@ -0,0 +1,9 @@
+Matrix3f A;
+Vector3f b;
+A << 1,2,3,  4,5,6,  7,8,9;
+b << 3, 3, 4;
+cout << "Here is the matrix A:" << endl << A << endl;
+cout << "Here is the vector b:" << endl << b << endl;
+Vector3f x;
+A.partialLu().solve(b, &x);
+cout << "The solution is:" << endl << x << endl;
diff --git a/doc/snippets/Tutorial_solve_triangular.cpp b/doc/snippets/Tutorial_solve_triangular.cpp
new file mode 100644
index 000000000..ff876f687
--- /dev/null
+++ b/doc/snippets/Tutorial_solve_triangular.cpp
@@ -0,0 +1,8 @@
+Matrix3f A;
+Vector3f b;
+A << 1,2,3,  0,5,6,  0,0,10;
+b << 3, 3, 4;
+cout << "Here is the matrix A:" << endl << A << endl;
+cout << "Here is the vector b:" << endl << b << endl;
+Vector3f x = A.triangularView<UpperTriangular>().solve(b);
+cout << "The solution is:" << endl << x << endl;
diff --git a/doc/snippets/Tutorial_solve_triangular_inplace.cpp b/doc/snippets/Tutorial_solve_triangular_inplace.cpp
new file mode 100644
index 000000000..64ae4eea1
--- /dev/null
+++ b/doc/snippets/Tutorial_solve_triangular_inplace.cpp
@@ -0,0 +1,6 @@
+Matrix3f A;
+Vector3f b;
+A << 1,2,3,  0,5,6,  0,0,10;
+b << 3, 3, 4;
+A.triangularView<UpperTriangular>().solveInPlace(b);
+cout << "The solution is:" << endl << b << endl;