remove unnecessary merge(.true.,.false.,...) (fortran-lang#959)

Author: perazz

Diff for: src/stdlib_math_is_close.fypp

@@ -23,7 +23,7 @@ contains
         equal_nan_ = optval(equal_nan, .false.)
 
         if (ieee_is_nan(a) .or. ieee_is_nan(b)) then
-            close = merge(.true., .false., equal_nan_ .and. ieee_is_nan(a) .and. ieee_is_nan(b))
+            close = equal_nan_ .and. ieee_is_nan(a) .and. ieee_is_nan(b)
         else
             close = abs(a - b) <= max( abs(optval(rel_tol, sqrt_eps_${k1}$)*max(abs(a), abs(b))), &
                                        abs(optval(abs_tol, 0.0_${k1}$)) )

Diff for: src/stdlib_stats_corr.fypp

@@ -202,7 +202,7 @@ contains
         case(1)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-             mask_ = merge(.true., .false., mask(:, i) .and. mask(:, j))
+             mask_ = mask(:, i) .and. mask(:, j)
              centeri_ = merge( x(:, i) - mean(x(:, i), mask = mask_),&
               #:if t1[0] == 'r'
                 0._${k1}$,&
@@ -227,7 +227,7 @@ contains
         case(2)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-             mask_ = merge(.true., .false., mask(i, :) .and. mask(j, :))
+             mask_ = mask(i, :) .and. mask(j, :)
              centeri_ = merge( x(i, :) - mean(x(i, :), mask = mask_),&
               #:if t1[0] == 'r'
                 0._${k1}$,&
@@ -274,11 +274,9 @@ contains
         case(1)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-             mask_ = merge(.true., .false., mask(:, i) .and. mask(:, j))
-             centeri_ = merge( x(:, i) - mean(x(:, i), mask = mask_),&
-                0._dp, mask_)
-             centerj_ = merge( x(:, j) - mean(x(:, j), mask = mask_),&
-                0._dp, mask_)
+             mask_ = mask(:, i) .and. mask(:, j)
+             centeri_ = merge( x(:, i) - mean(x(:, i), mask = mask_),0._dp, mask_)
+             centerj_ = merge( x(:, j) - mean(x(:, j), mask = mask_),0._dp, mask_)
 
              res(j, i) = dot_product( centerj_, centeri_)&
                  /sqrt(dot_product( centeri_, centeri_)*&
@@ -289,11 +287,9 @@ contains
         case(2)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-             mask_ = merge(.true., .false., mask(i, :) .and. mask(j, :))
-             centeri_ = merge( x(i, :) - mean(x(i, :), mask = mask_),&
-                0._dp, mask_)
-             centerj_ = merge( x(j, :) - mean(x(j, :), mask = mask_),&
-                0._dp, mask_)
+             mask_ = mask(i, :) .and. mask(j, :)
+             centeri_ = merge( x(i, :) - mean(x(i, :), mask = mask_),0._dp, mask_)
+             centerj_ = merge( x(j, :) - mean(x(j, :), mask = mask_),0._dp, mask_)
 
              res(j, i) = dot_product( centeri_, centerj_)&
                  /sqrt(dot_product( centeri_, centeri_)*&

Diff for: src/stdlib_stats_cov.fypp

@@ -186,7 +186,7 @@ contains
         case(1)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-             mask_ = merge(.true., .false., mask(:, i) .and. mask(:, j))
+             mask_ = mask(:, i) .and. mask(:, j)
              centeri_ = merge( x(:, i) - mean(x(:, i), mask = mask_),&
               #:if t1[0] == 'r'
                 0._${k1}$,&
@@ -211,7 +211,7 @@ contains
         case(2)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-             mask_ = merge(.true., .false., mask(i, :) .and. mask(j, :))
+             mask_ = mask(i, :) .and. mask(j, :)
              centeri_ = merge( x(i, :) - mean(x(i, :), mask = mask_),&
               #:if t1[0] == 'r'
                 0._${k1}$,&
@@ -260,11 +260,9 @@ contains
         case(1)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-              mask_ = merge(.true., .false., mask(:, i) .and. mask(:, j))
-              centeri_ = merge( x(:, i) - mean(x(:, i), mask = mask_),&
-                 0._dp, mask_)
-              centerj_ = merge( x(:, j) - mean(x(:, j), mask = mask_),&
-                 0._dp, mask_)
+              mask_ = mask(:, i) .and. mask(:, j)
+              centeri_ = merge( x(:, i) - mean(x(:, i), mask = mask_),0._dp, mask_)
+              centerj_ = merge( x(:, j) - mean(x(:, j), mask = mask_),0._dp, mask_)
 
               n = count(mask_)
               res(j, i) = dot_product( centerj_, centeri_)&
@@ -275,11 +273,9 @@ contains
         case(2)
           do i = 1, size(res, 2)
             do j = 1, size(res, 1)
-              mask_ = merge(.true., .false., mask(i, :) .and. mask(j, :))
-              centeri_ = merge( x(i, :) - mean(x(i, :), mask = mask_),&
-                 0._dp, mask_)
-              centerj_ = merge( x(j, :) - mean(x(j, :), mask = mask_),&
-                 0._dp, mask_)
+              mask_ = mask(i, :) .and. mask(j, :)
+              centeri_ = merge( x(i, :) - mean(x(i, :), mask = mask_),0._dp, mask_)
+              centerj_ = merge( x(j, :) - mean(x(j, :), mask = mask_),0._dp, mask_)
 
               n = count(mask_)
               res(j, i) = dot_product( centeri_, centerj_)&