Comment fixes

Author: WardBrian

stan/math/prim/constraint/sum_to_zero_constrain.hpp

@@ -83,7 +83,7 @@ inline plain_type_t<Vec> sum_to_zero_constrain(const Vec& y,
  * Return a vector with sum zero corresponding to the specified
  * free vector.
  *
- * The sum-to-zero transform is defined using a modified version of the
+ * The sum-to-zero transform is defined using a modified version of
  * the inverse of the isometric log ratio transform (ILR).
  * See:
  * Egozcue, Juan Jose; Pawlowsky-Glahn, Vera; Mateu-Figueras, Gloria;
@@ -111,15 +111,15 @@ inline plain_type_t<Vec> sum_to_zero_constrain(const Vec& y,
  * Return a vector with sum zero corresponding to the specified
  * free vector.
  *
- * The sum-to-zero transform is defined using a modified version of the
+ * The sum-to-zero transform is defined using a modified version of
  * the inverse of the isometric log ratio transform (ILR).
  * See:
  * Egozcue, Juan Jose; Pawlowsky-Glahn, Vera; Mateu-Figueras, Gloria;
  * Barcelo-Vidal, Carles (2003), "Isometric logratio transformations for
  * compositional data analysis", Mathematical Geology, 35 (3): 279–300,
  * doi:10.1023/A:1023818214614, S2CID 122844634
  *
- * This is a linear transform, with no Jacobian. 
+ * This is a linear transform, with no Jacobian.
  *
  * @tparam Jacobian unused
  * @tparam Vec A standard vector with inner type inheriting from

stan/math/prim/constraint/sum_to_zero_free.hpp

@@ -14,9 +14,13 @@ namespace math {
 /**
  * Return an unconstrained vector.
  *
- * The sum-to-zero transform is defined such that the first K-1
- * elements are unconstrained and the last element is the negative
- * sum of those elements.
+ * The sum-to-zero transform is defined using a modified version of the
+ * isometric log ratio transform (ILR).
+ * See:
+ * Egozcue, Juan Jose; Pawlowsky-Glahn, Vera; Mateu-Figueras, Gloria;
+ * Barcelo-Vidal, Carles (2003), "Isometric logratio transformations for
+ * compositional data analysis", Mathematical Geology, 35 (3): 279–300,
+ * doi:10.1023/A:1023818214614, S2CID 122844634
  *
  * @tparam ColVec a column vector type
  * @param z Vector of length K.

stan/math/rev/constraint/sum_to_zero_constrain.hpp

@@ -20,7 +20,7 @@ namespace math {
  * Return a vector with sum zero corresponding to the specified
  * free vector.
  *
- * The sum-to-zero transform is defined using a modified version of the
+ * The sum-to-zero transform is defined using a modified version of
  * the inverse of the isometric log ratio transform (ILR).
  * See:
  * Egozcue, Juan Jose; Pawlowsky-Glahn, Vera; Mateu-Figueras, Gloria;
@@ -69,15 +69,15 @@ inline auto sum_to_zero_constrain(const T& y) {
  * Return a vector with sum zero corresponding to the specified
  * free vector.
  *
- * The sum-to-zero transform is defined using a modified version of the
+ * The sum-to-zero transform is defined using a modified version of
  * the inverse of the isometric log ratio transform (ILR).
  * See:
  * Egozcue, Juan Jose; Pawlowsky-Glahn, Vera; Mateu-Figueras, Gloria;
  * Barcelo-Vidal, Carles (2003), "Isometric logratio transformations for
  * compositional data analysis", Mathematical Geology, 35 (3): 279–300,
  * doi:10.1023/A:1023818214614, S2CID 122844634
  *
- * This is a linear transform, with no Jacobian. 
+ * This is a linear transform, with no Jacobian.
  *
  * @tparam Vec type of the vector
  * @param y Free vector input of dimensionality K - 1.