Implementation of compliance elements and reusable internal coordinate infrastructure

man/xtb.1.adoc

@@ -242,7 +242,7 @@ NOTE: You can only select *one* runtyp, only the first runtyp will be used
 
 *--hess*::
     perform a numerical hessian calculation on input geometry
-
+    
 *--ohess* ['LEVEL']::
     perform a numerical hessian calculation on an `ancopt(3)` optimized
     geometry
@@ -251,6 +251,9 @@ NOTE: You can only select *one* runtyp, only the first runtyp will be used
     perform a biased numerical hessian calculation on an `ancopt(3)` optimized
     geometry
 
+    Hessian runs automatically perform a compliance analysis for nonperiodic
+    systems with more than one atom and no frozen atoms.
+
 *--o1nh*::
     perform the numerical hessian calculation using the ODLR approximation (O1NumHess)
 
@@ -414,6 +417,11 @@ OUTPUT
 *hessian*::
    contains the (not mass weighted) cartesian Hessian, *--namespace* compatible.
 
+*compliance.dat*::
+   compliance analysis from an eligible Hessian run. Lists every internal
+   coordinate with C~ii~ and 1/C~ii~, followed by up to 20 strongest
+   off-diagonal couplings per coordinate in descending order of magnitude.
+
 *xtbtopo.mol*::
    topology information written in molfile format.
 

src/CMakeLists.txt

@@ -23,6 +23,7 @@ add_subdirectory("docking")
 add_subdirectory("extern")
 add_subdirectory("freq")
 add_subdirectory("gfnff")
+add_subdirectory("internals")
 add_subdirectory("io")
 add_subdirectory("iff")
 add_subdirectory("main")
@@ -52,6 +53,7 @@ list(APPEND srcs
   "${dir}/broyden.f90"
   "${dir}/charge_model.f90"
   "${dir}/coffee.f90"
+  "${dir}/compliance.f90"
   "${dir}/constrain_param.f90"
   "${dir}/constrain_pot.f90"
   "${dir}/constr.f90"