Merge pull request #9 from jacobwilliams/8-real-kinds

added support for specifying the real kind via preprocessor flag

.github/workflows/CI.yml

@@ -1,5 +1,5 @@
 name: CI
-on: [push]
+on: [push, pull_request]
 jobs:
 
   Build:

README.md

@@ -15,13 +15,27 @@ A modern Fortran library for finding the roots of continuous scalar functions of
 A `fmp.toml` file is provided for compiling roots-fortran with the [Fortran Package Manager](https://github.com/fortran-lang/fpm). For example, to build:
 
 ```
-  fpm build --profile release
+fpm build --profile release
 ```
 
-And to run the unit tests:
+By default, the library is built with double precision (`real64`) real values. Explicitly specifying the real kind can be done using the following processor flags:
+
+Preprocessor flag | Kind  | Number of bytes
+----------------- | ----- | ---------------
+`REAL32`  | `real(kind=real32)`  | 4
+`REAL64`  | `real(kind=real64)`  | 8
+`REAL128` | `real(kind=real128)` | 16
+
+For example, to build a single precision version of the library, use:
+
+```
+fpm build --profile release --flag "-DREAL32"
+```
+
+To run the unit tests:
 
 ```
-  fpm test
+fpm test
 ```
 
 To use `roots-fortran` within your fpm project, add the following to your `fpm.toml` file:
@@ -36,7 +50,7 @@ or, to use a specific version:
 roots-fortran = { git="https://github.com/jacobwilliams/roots-fortran.git", tag = "1.0.0"  }
 ```
 
-To generate the documentation using [ford](https://github.com/Fortran-FOSS-Programmers/ford), run: ```ford roots-fortran.fobis```
+To generate the documentation using [ford](https://github.com/Fortran-FOSS-Programmers/ford), run: ```ford roots-fortran.md```
 
 ## Usage
 

fpm.toml

@@ -12,7 +12,7 @@ auto-examples = false
 auto-tests = true
 
 [dev-dependencies]
-pyplot-fortran = { git = "https://github.com/jacobwilliams/pyplot-fortran", tag = "3.1.0" }
+pyplot-fortran = { git = "https://github.com/jacobwilliams/pyplot-fortran", tag = "3.2.0" }
 
 [library]
 source-dir = "src"

src/root_module.f90 → src/root_module.F90

@@ -7,6 +7,19 @@
 !
 !### Author
 !  * Jacob Williams
+!
+!@note The default real kind (`wp`) can be
+!      changed using optional preprocessor flags.
+!      This library was built with real kind:
+#ifdef REAL32
+!      `real(kind=real32)` [4 bytes]
+#elif REAL64
+!      `real(kind=real64)` [8 bytes]
+#elif REAL128
+!      `real(kind=real128)` [16 bytes]
+#else
+!      `real(kind=real64)` [8 bytes]
+#endif
 
     module root_module
 
@@ -16,7 +29,16 @@ module root_module
 
     private
 
-    integer,parameter,public :: root_module_rk = real64  !! real kind used by this module
+#ifdef REAL32
+    integer,parameter,public :: root_module_rk = real32   !! real kind used by this module [4 bytes]
+#elif REAL64
+    integer,parameter,public :: root_module_rk = real64   !! real kind used by this module [8 bytes]
+#elif REAL128
+    integer,parameter,public :: root_module_rk = real128  !! real kind used by this module [16 bytes]
+#else
+    integer,parameter,public :: root_module_rk = real64   !! real kind used by this module [8 bytes]
+#endif
+
     integer,parameter :: wp = root_module_rk  !! local copy of `root_module_rk` with a shorter name
     integer,parameter :: name_len = 32  !! max length of the method names
 

test/root_tests.f90

@@ -132,24 +132,27 @@ subroutine test()
         integer :: irepeat !! test repeat counter
         integer :: i
         real(wp) :: atol, rtol, ftol
+        real(wp) :: tol_for_check !! for pass/fail check
 
         integer,parameter :: n_repeat = 1  !! number of times to repeat each test for timing purposes
-        real(wp),parameter :: tol_for_check = 1.0e-7_wp  !! for pass/fail check
         integer,parameter :: maxiter = 1000 !! maximum number of iterations
 
         select case (wp)
         case(real32)
             atol = 1.0e-5_wp
             rtol = 1.0e-5_wp
             ftol = 1.0e-5_wp
+            tol_for_check = 1.0e-4_wp
         case(real64)
             atol = 1.0e-15_wp
             rtol = 1.0e-13_wp
             ftol = 1.0e-15_wp
+            tol_for_check = 1.0e-7_wp
         case(real128)
             atol = 1.0e-25_wp
             rtol = 1.0e-23_wp
             ftol = 1.0e-25_wp
+            tol_for_check = 1.0e-16_wp
         case default
             error stop 'unknown real kind'
         end select

test/root_tests_oo.f90

@@ -13,9 +13,9 @@ program root_tests_oo
     integer :: iflag
     character(len=1000) :: line
 
-    real(wp),parameter :: ftol = 1.0e-15_wp
-    real(wp),parameter :: rtol = 1.0e-13_wp
-    real(wp),parameter :: atol = 1.0e-16_wp
+    real(wp),parameter :: ftol = epsilon(1.0_wp) * 10    !1.0e-15_wp
+    real(wp),parameter :: rtol = epsilon(1.0_wp) * 100   !1.0e-13_wp
+    real(wp),parameter :: atol = epsilon(1.0_wp) * 1     !1.0e-16_wp
     integer,parameter  :: maxiter = 1000
 
     character(len=*),parameter :: fmt  = '(A25,   1X,A25,   1X,A25,  1X,A5,1X,A5)' !! format for header