Added example for symtridiagonal and hermtridiagonal.

Author: loiseaujc

doc/specs/stdlib_specialmatrices.md

@@ -114,7 +114,7 @@ Symmetric tridiagonal matrices are available with all supported data types as `s
 
 #### Syntax
 
-- To construct a symmetric tridiagonal matrix from already allocated arrays `dv` (main diagonal, size `n`) and `ev` (upper diagonal, size `n-1`):
+- To construct a symmetric tridiagonal matrix from already allocated arrays `dv` (main diagonal, size `n`, only its real part is being referenced) and `ev` (upper diagonal, size `n-1`):
 
 `A = ` [[stdlib_specialmatrices(module):symtridiagonal(interface)]] `(dv, ev)`
 
@@ -175,7 +175,7 @@ Note that only the real parts of the diagonal elements `dv` are being used to co
 #### Example
 
 ```fortran
-{!example/specialmatrices/example_hermtridiagonal_dp_type.f90!}
+{!example/specialmatrices/example_hermtridiagonal_cdp_type.f90!}
 ```
 
 ## Specialized drivers for linear algebra tasks

example/specialmatrices/example_hermtridiagonal_cdp_type.f90

@@ -0,0 +1,18 @@
+program example_hermtridiagonal_matrix
+   use stdlib_linalg_constants, only: dp
+   use stdlib_specialmatrices
+   implicit none
+
+   integer, parameter :: n = 5
+   type(hermtridiagonal_cdp_type) :: A
+   complex(dp) :: dv(n), ev(n - 1)
+   real(dp) :: data(n, 2)
+
+   ! Generate random tridiagonal elements.
+   call random_number(data); dv = cmplx(data(:, 1), 0*data(:, 2), kind=dp)
+   call random_number(data); ev = cmplx(data(:n - 1, 1), data(:n - 1, 2), kind=dp)
+
+   ! Create the corresponding Hermitian tridiagonal matrix.
+   A = hermtridiagonal(dv, ev)
+
+end program example_hermtridiagonal_matrix

example/specialmatrices/example_symtridiagonal_dp_type.f90

@@ -0,0 +1,17 @@
+program example_symtridiagonal_matrix
+   use stdlib_linalg_constants, only: dp
+   use stdlib_specialmatrices
+   implicit none
+
+   integer, parameter :: n = 5
+   type(symtridiagonal_dp_type) :: A
+   real(dp) :: dv(n), ev(n - 1)
+
+   ! Generate random tridiagonal elements.
+   call random_number(dv)
+   call random_number(ev)
+
+   ! Create the corresponding Symmetric tridiagonal matrix.
+   A = symtridiagonal(dv, ev)
+
+end program example_symtridiagonal_matrix