Merge pull request #830 from stan-dev/avehtari-patch-1

Update one-dimensional-integrals.qmd

src/stan-users-guide/one-dimensional-integrals.qmd

@@ -48,9 +48,11 @@ not a function of our parameters.
 The function defining the integrand must have exactly the argument types and
 return type of `normal_density` above, though argument naming is not important.
 Even if `x_r` and `x_i` are unused in the integrand, they must be
-included in the function signature. This may require passing in zero-length arrays
-for data or a zero-length vector for parameters if the integral does not involve
-data or parameters.
+included in the function signature. Even if the integral does not involve some of these,
+they must still be supplied some value. The most efficient will be a zero-length array
+or vector, which can be created with rep_array(0, 0) and rep_vector(0, 0), respectively.
+Other options include an uninitialized variable declared with size 0, which is equivalent
+to the above, or any easy value, such as size 1 array created with {0}.
 
 ## Calling the integrator