Remove variable_error checking from maths library

CMakeLists.txt

@@ -88,7 +88,6 @@ LIST(APPEND PROCESS_SRCS
     ife_variables.f90
     heat_transport_variables.f90
     buildings_variables.f90
-    maths_library.f90
     iteration_variables.f90
     water_usage_variables.f90
     constraint_equations.f90

source/fortran/constraint_equations.f90

@@ -47,7 +47,6 @@ subroutine constraint_eqns(m,ieqn,cc,con,err,symbol,units)
     !!
     !! 1.
     use numerics, only: icc
-    use maths_library, only: variable_error
 
     implicit none
 
@@ -307,9 +306,7 @@ subroutine constraint_eqns(m,ieqn,cc,con,err,symbol,units)
         if (present(units))  units(i)  = tmp_units
       end if
 
-      ! Crude method of catching NaN errors
-      !if ((abs(cc(i)) > 9.99D99).or.(cc(i) /= cc(i))) then
-      if (variable_error(cc(i))) then
+      if (isnan(cc(i)).or.(abs(cc(i))>9.99D99)) then
 
         ! Add debugging lines as appropriate...
         select case (icc(i))

source/fortran/iteration_variables.f90

@@ -3933,7 +3933,6 @@ subroutine loadxc
     ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
     use constants, only: nout
-    use maths_library, only: variable_error
     use error_handling, only: idiags, fdiags, report_error
     use numerics, only: nvar, xcm, ixc, name_xc, lablxc, scafc, scale
     use physics_variables, only: i_plasma_current
@@ -4152,10 +4151,7 @@ subroutine loadxc
           call report_error(55)
        end if
 
-       !  Crude method of catching NaN errors
-
-       !if ( (abs(xcm(i)) > 9.99D99).or.(xcm(i) /= xcm(i)) ) then
-       if ( variable_error(xcm(i)) ) then
+       if ((isnan(xcm(i)).or.(abs(xcm(i))>9.99D99))) then
           idiags(1) = i ; idiags(2) = ixc(i) ; fdiags(1) = xcm(i)
           call report_error(56)
        end if
@@ -4190,7 +4186,6 @@ subroutine convxc(xc,nn)
 
     use error_handling, only: idiags, fdiags, report_error
     use numerics, only: ipnvars, scale, ixc, lablxc
-    use maths_library, only: variable_error
 #ifndef dp
     use, intrinsic :: iso_fortran_env, only: dp=>real64
 #endif
@@ -4406,7 +4401,7 @@ subroutine convxc(xc,nn)
        !  Crude method of catching NaN errors
 
        !if ((abs(xc(i)) > 9.99D99).or.(xc(i) /= xc(i))) then
-       if(variable_error(xc(i)))then
+       if (isnan(xc(i)).or.(abs(xc(i))>9.99D99)) then
           idiags(1) = i ; idiags(2) = ixc(i) ; fdiags(1) = xc(i)
           call report_error(59)
        end if

source/fortran/output.f90

@@ -422,7 +422,6 @@ subroutine ovarre(file,descr,varnam,value,output_flag)
     use numerics, only: name_xc
 		use global_variables, only: icase, vlabel
 		use constants, only: mfile, nout
-		use maths_library, only: variable_error
     implicit none
 
     !  Arguments
@@ -502,7 +501,6 @@ subroutine ovarin(file,descr,varnam,value,output_flag)
     use numerics, only: name_xc, icc, ioptimz
 		use global_variables, only: xlabel_2, iscan_global
 		use constants, only: mfile, nout
-		use maths_library, only: variable_error
     implicit none
 
     !  Arguments
@@ -619,7 +617,6 @@ subroutine ocosts(file,ccode,descr,value)
     ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
 		use constants, only: pi, mfile, nplot, twopi
-		use maths_library, only: variable_error
     implicit none
 
     !  Arguments
@@ -667,7 +664,6 @@ subroutine obuild(file,descr,thick,total,variable_name)
 
     use numerics, only: boundl, boundu
 		use constants, only: electron_charge
-		use maths_library, only: variable_error
     implicit none
 
     !  Arguments