make eye default type: real(dp)

Author: perazz

doc/specs/stdlib_linalg.md

@@ -249,28 +249,24 @@ Constructs the identity matrix.
 
 - `dim1`: A scalar of type `integer`. This is an `intent(in)` argument and specifies the number of rows.
 - `dim2`: A scalar of type `integer`. This is an optional `intent(in)` argument specifying the number of columns. If not provided, the matrix is square (`dim1 = dim2`).
-- `mold`: A scalar of any supported `integer`, `real`, or `complex` type. This is an optional `intent(in)` argument. If provided, the returned identity matrix will have the same type and kind as `mold`. If not provided, the matrix will be of type `integer(int8)` by default.
+- `mold`: A scalar of any supported `integer`, `real`, or `complex` type. This is an optional `intent(in)` argument. If provided, the returned identity matrix will have the same type and kind as `mold`. If not provided, the matrix will be of type `real(real64)` by default.
 
 ### Return value
 
 Returns the identity matrix, with ones on the main diagonal and zeros elsewhere. 
 
-- By default, the return value is of type `integer(int8)`, which is recommended for storage efficiency.
+- By default, the return value is of type `real(real64)`, which is recommended for arithmetic safety.
 - If the `mold` argument is provided, the return value will match the type and kind of `mold`, allowing for arbitrary `integer`, `real`, or `complex` return types.
 
-#### Warning
-
-When using the default `integer(int8)` type, be cautious when performing arithmetic operations, as integer division may occur. For example:
+### Example
 
 ```fortran
-!> Caution: default type is `integer`
-A = eye(2,2)/2             !! A == 0.0 due to integer division
-!> Recommend using a non-integer type for division
-A = eye(2,2, mold=1.0)/2   !! A == diag([0.5, 0.5])
+!> Return default type (real64)
+A = eye(2,2)/2             !! A == diag([0.5_dp, 0.5_dp])
+!> Return 32-bit complex
+A = eye(2,2, mold=(0.0,0.0))/2   !! A == diag([(0.5,0.5), (0.5,0.5)])
 ```
 
-### Example
-
 ```fortran
 {!example/linalg/example_eye1.f90!}
 ```

src/stdlib_linalg.fypp

@@ -1342,7 +1342,7 @@ contains
 
         integer, intent(in) :: dim1
         integer, intent(in), optional :: dim2
-        ${t1}$, intent(in) #{if 'int8' in t1}#, optional #{endif}#:: mold
+        ${t1}$, intent(in) #{if t1 == 'real(dp)'}#, optional #{endif}#:: mold        
         ${t1}$, allocatable :: result(:, :)
 
         integer :: dim2_