add real and complex examples

Author: perazz

example/linalg/CMakeLists.txt

@@ -18,3 +18,5 @@ ADD_EXAMPLE(state1)
 ADD_EXAMPLE(state2)
 ADD_EXAMPLE(blas_gemv)
 ADD_EXAMPLE(lapack_getrf)
+ADD_EXAMPLE(solve1)
+ADD_EXAMPLE(solve2)

example/linalg/example_solve1.f90

@@ -0,0 +1,26 @@
+program example_solve1
+  use stdlib_linalg_constants, only: sp
+  use stdlib_linalg, only: solve, linalg_state_type 
+  implicit none
+
+  real(sp), allocatable :: A(:,:),b(:),x(:)
+
+  ! Solve a system of 3 linear equations: 
+  !  4x + 3y + 2z =  25
+  ! -2x + 2y + 3z = -10
+  !  3x - 5y + 2z =  -4
+
+  ! Note: Fortran is column-major! -> transpose 
+  A = transpose(reshape([ 4, 3, 2, &
+                         -2, 2, 3, &
+                          3,-5, 2], [3,3])) 
+  b = [25,-10,-4]
+
+  ! Get coefficients of y = coef(1) + x*coef(2) + x^2*coef(3)
+  x = solve(A,b) 
+
+  print *, 'solution: ',x
+  ! 5.0, 3.0, -2.0
+
+end program example_solve1
+

example/linalg/example_solve2.f90

@@ -0,0 +1,26 @@
+program example_solve2
+  use stdlib_linalg_constants, only: sp
+  use stdlib_linalg, only: solve, linalg_state_type 
+  implicit none
+
+  complex(sp), allocatable :: A(:,:),b(:),x(:)
+
+  ! Solve a system of 3 complex linear equations: 
+  !  2x +      iy + 2z = (5-i)
+  ! -ix + (4-3i)y + 6z = i
+  !  4x +      3y +  z = 1
+
+  ! Note: Fortran is column-major! -> transpose 
+  A = transpose(reshape([(2.0, 0.0),(0.0, 1.0),(2.0,0.0), &
+                         (0.0,-1.0),(4.0,-3.0),(6.0,0.0), &
+                         (4.0, 0.0),(3.0, 0.0),(1.0,0.0)] , [3,3])) 
+  b = [(5.0,-1.0),(0.0,1.0),(1.0,0.0)]
+
+  ! Get coefficients of y = coef(1) + x*coef(2) + x^2*coef(3)
+  x = solve(A,b) 
+
+  print *, 'solution: ',x
+  !   (1.0947,0.3674) (-1.519,-0.4539) (1.1784,-0.1078)
+
+end program example_solve2
+

src/stdlib_linalg.fypp

@@ -31,6 +31,9 @@ module stdlib_linalg
   public :: is_triangular
   public :: is_hessenberg
 
+  ! Export linalg error handling
+  public :: linalg_state_type, linalg_error_handling
+
   interface diag
     !! version: experimental
     !!