use explicit-shape-arrays instead

Author: St-Maxwell

src/stdlib_linalg.fypp

@@ -89,8 +89,8 @@ module stdlib_linalg
     !! Computes the cross product of two vectors, returning a rank-1 and size-3 array
     !! ([Specification](../page/specs/stdlib_linalg.html#cross_product-computes-the-cross-product-of-two-3-d-vectors))
     #:for k1, t1 in RCI_KINDS_TYPES
-      module function cross_product_${t1[0]}$${k1}$(a, b) result(res)
-        ${t1}$, intent(in) :: a(:), b(:)
+      pure module function cross_product_${t1[0]}$${k1}$(a, b) result(res)
+        ${t1}$, intent(in) :: a(3), b(3)
         ${t1}$ :: res(3)
       end function cross_product_${t1[0]}$${k1}$
     #:endfor

src/stdlib_linalg_cross_product.fypp

@@ -7,13 +7,10 @@ submodule (stdlib_linalg) stdlib_linalg_cross_product
 contains
 
     #:for k1, t1 in RCI_KINDS_TYPES
-    module function cross_product_${t1[0]}$${k1}$(a, b) result(res)
-        ${t1}$, intent(in) :: a(:), b(:)
+    pure module function cross_product_${t1[0]}$${k1}$(a, b) result(res)
+        ${t1}$, intent(in) :: a(3), b(3)
         ${t1}$ :: res(3)
 
-        if (size(a) /= 3 .or. size(b) /= 3) &
-            call error_stop("The size of a and b should be 3.")
-
         res(1) = a(2) * b(3) - a(3) * b(2)
         res(2) = a(3) * b(1) - a(1) * b(3)
         res(3) = a(1) * b(2) - a(2) * b(1)