[stdlib_linalg] Add zeros, ones function.

doc/specs/stdlib_linalg.md

@@ -206,3 +206,78 @@ program demo_outer_product
     !A = reshape([3., 6., 9., 4., 8., 12.], [3,2])
 end program demo_outer_product
 ```
+
+## `zeros/ones`
+
+### Description
+
+`zeros` creates a rank-1 or rank-2 `array` of the given shape, filled completely with `0` `integer` type values.  
+`ones` creates a rank-1 or rank-2 `array` of the given shape, filled completely with `1` `integer` type values.
+
+### Status
+
+Experimental
+
+### Class
+
+Pure function.
+
+### Syntax
+
+For rank-1 array:  
+`result = [[stdlib_linalg(module):zeros(interface)]](dim)`  
+`result = [[stdlib_linalg(module):ones(interface)]](dim)`
+
+For rank-2 array:  
+`result = [[stdlib_linalg(module):zeros(interface)]](dim1, dim2)`  
+`result = [[stdlib_linalg(module):ones(interface)]](dim1, dim2)`
+
+
+### Arguments
+
+`dim/dim1`: Shall be an `integer` type.
+This is an `intent(in)` argument.
+
+`dim2`: Shall be an `integer` type.
+This is an `intent(in)` argument.
+
+### Return value
+
+Returns a rank-1 or rank-2 `array` of the given shape, filled completely with either `0` or `1` `integer` type values.
+
+#### Warning
+
+Since the result of `ones` is of `integer` type, one should be careful about using it in arithmetic expressions. For example:
+```fortran
+real :: A(:,:)
+
+!> Be careful
+A = ones(2,2)/2     !! A = 1/2 = 0.0
+
+!> Recommend
+A = ones(2,2)/2.0   !! A = 1/2.0 = 0.5
+```
+
+### Example
+
+```fortran
+program demo
+    use stdlib_linalg, only: zeros, ones
+    implicit none
+    real, allocatable :: A(:,:)
+    integer :: iA(2)
+    complex :: cA(2), cB(2,3)
+
+    A = zeros(2,2)          !! [0.0,0.0; 0.0,0.0] (Same as `reshape(spread(0,1,2*2),[2,2])`)
+    A = ones(4,4)           !! [1.0,1.0,1.0,1.0; 1.0,1.0,1.0,1.0; 1.0,1.0,1.0,1.0; 1.0,1.0,1.0 1.0]
+    A = 2.0*ones(2,2)       !! [2.0,2.0; 2.0,2.0]
+
+    print *, reshape(ones(2*3*4),[2,3,4])    !! Same as `reshape(spread(1,1,2*3*4),[2,3,4])`
+
+    iA = ones(2)            !! [1,1] (Same as `spread(1,1,2)`)
+    cA = ones(2)            !! [(1.0,0.0),(1.0,0.0)]
+    cA = (1.0,1.0)*ones(2)  !! [(1.0,1.0),(1.0,1.0)]
+    cB = ones(2,3)          !! [(1.0,0.0),(1.0,0.0),(1.0,0.0); (1.0,0.0),(1.0,0.0),(1.0,0.0)]
+
+end program demo
+```

src/Makefile.manual

@@ -81,7 +81,8 @@ stdlib_io.o: \
 	stdlib_optval.o \
 	stdlib_kinds.o
 stdlib_linalg.o: \
-	stdlib_kinds.o
+	stdlib_kinds.o \
+    stdlib_string_type.o
 stdlib_linalg_diag.o: \
 	stdlib_linalg.o \
 	stdlib_kinds.o

src/stdlib_linalg.fypp

@@ -4,14 +4,16 @@ module stdlib_linalg
   !!Provides a support for various linear algebra procedures
   !! ([Specification](../page/specs/stdlib_linalg.html))
   use stdlib_kinds, only: sp, dp, qp, &
-    int8, int16, int32, int64
+    int8, int16, int32, int64, lk, c_bool
+  use stdlib_string_type, only: string_type
   implicit none
   private
 
   public :: diag
   public :: eye
   public :: trace
   public :: outer_product
+  public :: zeros, ones
 
   interface diag
     !! version: experimental
@@ -80,6 +82,26 @@ module stdlib_linalg
     #:endfor
   end interface outer_product
 
+    !> Version: experimental
+    !>
+    !> `ones` creates a rank-1 or rank-2 array of the given shape, 
+    !>  filled completely with `1` `integer` type values. 
+    !> ([Specification](../page/specs/stdlib_linalg.html#zerosones))
+    interface ones
+        procedure :: ones_1_default
+        procedure :: ones_2_default
+    end interface ones
+
+    !> Version: experimental
+    !>
+    !> `zeros` creates a rank-1 or rank-2 array of the given shape, 
+    !>  filled completely with `0` `integer` type values. 
+    !> ([Specification](../page/specs/stdlib_linalg.html#zerosones))
+    interface zeros
+        procedure :: zeros_1_default
+        procedure :: zeros_2_default
+    end interface zeros
+
 contains
 
     function eye(n) result(res)
@@ -108,4 +130,41 @@ contains
         end do
       end function trace_${t1[0]}$${k1}$
     #:endfor
-end module
+
+    !> `ones` creates a rank-1 array, filled completely with `1` `integer` type values.
+    pure function ones_1_default(dim) result(result)
+        integer, intent(in) :: dim
+        integer, allocatable :: result(:)
+
+        allocate(result(dim), source=1)
+
+    end function ones_1_default
+
+    !> `ones` creates a rank-2 array, filled completely with `1` `integer` type values.
+    pure function ones_2_default(dim1, dim2) result(result)
+        integer, intent(in) :: dim1, dim2
+        integer, allocatable :: result(:, :)
+
+        allocate(result(dim1, dim2), source=1)
+
+    end function ones_2_default
+
+    !> `zeros` creates a rank-1 array, filled completely with `0` `integer` type values.
+    pure function zeros_1_default(dim) result(result)
+        integer, intent(in) :: dim
+        integer, allocatable :: result(:)
+
+        allocate(result(dim), source=0)
+
+    end function zeros_1_default
+
+    !> `zeros` creates a rank-2 array, filled completely with `0` `integer` type values.
+    pure function zeros_2_default(dim1, dim2) result(result)
+        integer, intent(in) :: dim1, dim2
+        integer, allocatable :: result(:, :)
+
+        allocate(result(dim1, dim2), source=0)
+
+    end function zeros_2_default
+
+end module stdlib_linalg

src/tests/Makefile.manual

@@ -11,3 +11,4 @@ all test clean:
 	$(MAKE) -f Makefile.manual --directory=stats $@
 	$(MAKE) -f Makefile.manual --directory=string $@
 	$(MAKE) -f Makefile.manual --directory=math $@
+	$(MAKE) -f Makefile.manual --directory=linalg $@

src/tests/linalg/CMakeLists.txt

@@ -1,2 +1,3 @@
 ADDTEST(linalg)
+ADDTEST(linalg_ones_zeros)
 

src/tests/linalg/Makefile.manual

@@ -0,0 +1,4 @@
+PROGS_SRC = test_linalg_ones_zeros.f90
+
+
+include ../Makefile.manual.test.mk

src/tests/linalg/test_linalg_ones_zeros.f90

@@ -0,0 +1,81 @@
+!> SPDX-Identifier: MIT
+module test_linalg_ones_zeros
+
+    use stdlib_linalg, only: zeros, ones
+    use stdlib_error, only: check
+    use stdlib_string_type
+    implicit none
+
+    logical, parameter :: warn = .false.
+
+contains
+
+    !> `zeros` tests
+    subroutine test_linalg_zeros_integer
+        call check(all(zeros(2) == [0, 0]), msg="all(zeros(2)==[0, 0] failed", warn=warn)
+        call check(all(zeros(2, 2) == reshape([0, 0, 0, 0], [2, 2])), &
+                   msg="all(zeros(2,2)==reshape([0, 0, 0, 0],[2,2]) failed", warn=warn)
+    end subroutine test_linalg_zeros_integer
+
+    subroutine test_linalg_zeros_real
+        real, allocatable :: rA(:), rB(:, :)
+        rA = zeros(2)
+        call check(all(rA == spread(0.0_4, 1, 2)), msg="all(rA == spread(0.0_4,1,2)) failed", warn=warn)
+        rB = zeros(2, 2)
+        call check(all(rB == reshape(spread(0.0_4, 1, 2*2), [2, 2])), &
+                   msg="all(rB == reshape(spread(0.0_4, 1,2*2),[2,2])) failed", warn=warn)
+    end subroutine test_linalg_zeros_real
+
+    subroutine test_linalg_zeros_complex
+        complex, allocatable :: cA(:), cB(:, :)
+        cA = zeros(2)
+        call check(all(cA == spread((0.0_4, 0.0_4), 1, 2)), msg="all(cA == spread((0.0_4,0.0_4),1,2)) failed", warn=warn)
+        cB = zeros(2, 2)
+        call check(all(cB == reshape(spread((0.0_4, 0.0_4), 1, 2*2), [2, 2])), &
+                   msg="all(cB == reshape(spread((0.0_4,0.0_4), 1, 2*2), [2, 2])) failed", warn=warn)
+    end subroutine test_linalg_zeros_complex
+
+    !> `ones` tests
+    subroutine test_linalg_ones_integer
+        call check(all(ones(2) == [1, 1]), msg="all(ones(2)==[1, 1] failed", warn=warn)
+        call check(all(ones(2, 2) == reshape([1, 1, 1, 1], [2, 2])), &
+                   msg="all(ones(2,2)==reshape([1, 1, 1, 1],[2,2])) failed", warn=warn)
+    end subroutine test_linalg_ones_integer
+
+    subroutine test_linalg_ones_real
+        real, allocatable :: rA(:), rB(:, :)
+        rA = ones(2)
+        call check(all(rA == spread(1.0_4, 1, 2)), msg="all(rA == spread(1.0_4,1,2)) failed", warn=warn)
+        rB = ones(2, 2)
+        call check(all(rB == reshape(spread(1.0_4, 1, 2*2), [2, 2])), &
+                   msg="all(rB == reshape(spread(1.0_4, 1, 2*2), [2, 2])) failed", warn=warn)
+    end subroutine test_linalg_ones_real
+
+    subroutine test_linalg_ones_complex
+        complex, allocatable :: cA(:), cB(:, :)
+        cA = ones(2)
+        call check(all(cA == spread((1.0_4, 0.0_4), 1, 2)), msg="all(cA == spread((1.0_4,0.0_4),1,2)) failed", warn=warn)
+        cB = ones(2, 2)
+        call check(all(cB == reshape(spread((1.0_4, 0.0_4), 1, 2*2), [2, 2])), &
+                   msg="all(cB == reshape(spread((1.0_4, 0.0_4), 1, 2*2), [2, 2])) failed", warn=warn)
+    end subroutine test_linalg_ones_complex
+
+end module test_linalg_ones_zeros
+
+program tester
+
+    use test_linalg_ones_zeros
+
+    print *, "`zeros` tests"
+    call test_linalg_zeros_integer
+    call test_linalg_zeros_real
+    call test_linalg_zeros_complex
+
+    print *, "`ones` tests"
+    call test_linalg_ones_integer
+    call test_linalg_ones_real
+    call test_linalg_ones_complex
+
+    print *, "All tests in `test_linalg_ones_zeros` passed"
+
+end program tester