Rename internal functions stretch_2[s] to sqrt_2[s]

CHANGELOG.md

@@ -3,6 +3,9 @@ All notable changes to this project will be documented in this file. The format
 
 ## [Unreleased]
 
+### Changed
+- Rename internal matrix square-root from `stretch_2` and `stretch_2s` to `sqrt_2` and `sqrt_2s`. This does not affect the public API which remains unchanged as (matrix) square root `sqrt(T)`.
+
 ### Fixed
 - Fix the orientation of `rotation_matrix(phi,2)` for a rotation matrix around axis 2. Also fix the docs for `rotation_matrix(phi,1)` and `rotation_matrix(phi,3)`.
 

docs/api/functions/squareroot.md

@@ -8,7 +8,7 @@ grand_parent: API Reference
 
 ## Square Root
 
-Tensorial square root of a positive definite rank 2 Tensor. For algorithmic details see [Franka, L.P. (1988)](https://inis.iaea.org/search/search.aspx?orig_q=RN:20064555). This function can be used to obtain the stretch tensor.
+Tensorial (matrix) square root of a positive definite rank 2 Tensor. For algorithmic details see [Franka, L.P. (1988)](https://inis.iaea.org/search/search.aspx?orig_q=RN:20064555). This function can be used to obtain the stretch tensor. For a rank 1 Tensor (vector), the element-wise square root is returned.
 
 $$
 \begin{align}

ttb/libsqrt.f

@@ -8,7 +8,7 @@ function sqrt_1(T)
 
        end function sqrt_1
 
-       function stretch_2(T)
+       function sqrt_2(T)
         ! Source:
         !
         ! Franca, L.P. (1989): AN ALGORITHM TO COMPUTE
@@ -17,7 +17,7 @@ function stretch_2(T)
         implicit none
 
         type(Tensor2), intent(in) :: T
-        type(Tensor2) :: stretch_2
+        type(Tensor2) :: sqrt_2
 
         real(kind=8) :: I_T,II_T,III_T,I_U,II_U,III_U,k,l,lam,phi
 
@@ -30,7 +30,7 @@ function stretch_2(T)
         ! Isotropy check
         if (dabs(k).le.1.0d-8) then
          lam = (I_T/3.)**(1./2.)
-         stretch_2 = lam * identity2(T)
+         sqrt_2 = lam * identity2(T)
          return
         end if
 
@@ -46,12 +46,12 @@ function stretch_2(T)
 
         print *, 'test', l,k,1-l**2/k**3
 
-        stretch_2 = 1./(I_U*II_U-III_U)
+        sqrt_2 = 1./(I_U*II_U-III_U)
      *           *(I_U*III_U*identity2(T) + (I_U**2-II_U)*T-T**2)
 
-       end function stretch_2
+       end function sqrt_2
 
-       function stretch_2s(T)
+       function sqrt_2s(T)
         ! Source:
         !
         ! Franca, L.P. (1989): AN ALGORITHM TO COMPUTE
@@ -60,7 +60,7 @@ function stretch_2s(T)
         implicit none
 
         type(Tensor2s), intent(in) :: T
-        type(Tensor2s) :: stretch_2s
+        type(Tensor2s) :: sqrt_2s
 
         real(kind=8) :: I_T,II_T,III_T,I_U,II_U,III_U,k,l,lam,phi
 
@@ -73,7 +73,7 @@ function stretch_2s(T)
         ! Isotropy check
         if (k.le.1.0d-8) then
          lam = (I_T/3.)**(1./2.)
-         stretch_2s = lam * identity2(T)
+         sqrt_2s = lam * identity2(T)
          return
         end if
 
@@ -87,7 +87,7 @@ function stretch_2s(T)
         I_U = lam + dsqrt(-lam**2+I_T+2.*III_U/lam)
         II_U = (I_U**2-I_T)/2.
 
-        stretch_2s = 1./(I_U*II_U-III_U)
+        sqrt_2s = 1./(I_U*II_U-III_U)
      *           *(I_U*III_U*identity2(T) + (I_U**2-II_U)*T-T*T)
 
-       end function stretch_2s
+       end function sqrt_2s

ttb/ttb_library.f

@@ -268,14 +268,14 @@ module Tensor
 
        interface sqrt
        module procedure sqrt_1
-       module procedure stretch_2
-       module procedure stretch_2s
+       module procedure sqrt_2
+       module procedure sqrt_2s
        end interface
 
        interface dsqrt
        module procedure sqrt_1
-       module procedure stretch_2
-       module procedure stretch_2s
+       module procedure sqrt_2
+       module procedure sqrt_2s
        end interface
 
        interface rotation_matrix

version.txt

@@ -1 +1 @@
-2.1.0-dev
+2.2.0-dev