function to count amount of trailing zeroes

gpl_module.f90

@@ -44,12 +44,13 @@ CONTAINS
     ! used to compute the value of GPL when all zi are zero
     integer :: l
     complex(kind=prec) :: y, GPL_zero_zi
-    print*, 'computed value using zero'
+    print*, 'computed value using zi = 0'
     GPL_zero_zi = 1.0d0/factorial(l) * log(y) ** l
 
   END FUNCTION GPL_zero_zi
 
   FUNCTION  G_with_flat_args(z_flat,y) result(res)
+    ! Calls G function with flat arguments, that is, zeroes not passed through the m's. 
     complex(kind=prec) :: z_flat(:), y, res
     complex(kind=prec), allocatable :: z(:)
     integer :: m_prime(size(z_flat)), condensed_size
@@ -73,29 +74,31 @@ CONTAINS
     ! computes the generalized polylogarithm G_{m1,..mk} (z1,...zk; y)
     ! assumes zero arguments expressed through the m's
     
-    integer :: m(:), k, i
+    integer :: m(:), k, i, kminusj
     complex(kind=prec) :: z(:), x(k), y, res, c(sum(m)+1,sum(m)+1), z_flat(sum(m)), a(sum(m)-1)
 
     ! print*, 'z = ', abs(get_flattened_z(m,z))
     ! are all z_i = 0 ? 
-    if(k == 1 .and. abs(z(1)) < zero) then
+    if(k == 1 .and. abs(z(1)) == 0) then
       ! assumes that the zeros at the beginning are passed through m1
       res = GPL_zero_zi(m(1),y)
       return
     end if
 
     !  need to remove trailing  zeros?
-    if(abs(z(k)) < zero ) then
-      print*, 'need to remove trailing zeros'
+    if(abs(z(k)) == 0 ) then
+      print*, 'need to remove trailing zeros'   ! which we do in flat form
       ! flatten z
       z_flat = get_flattened_z(m,z)
-      a = z_flat(1: (size(z_flat)-1))
-      c = shuffle_with_zero(a)
-      res = G_with_flat_args(a,y)*log(y)
-      do  i = 2,k
-        res = res - G_with_flat_args(c(i,:),y)
-      end do
-      return
+      res = G_with_flat_args(z_flat,y)
+
+      ! a = z_flat(1: (size(z_flat)-1))
+      ! c = shuffle_with_zero(a)
+      ! res = G_with_flat_args(a,y)*log(y)
+      ! do  i = 2,k
+      !   res = res - G_with_flat_args(c(i,:),y)
+      ! end do
+      ! return
     end  if
 
     ! need make convergent?

test.f90

@@ -85,11 +85,9 @@ CONTAINS
     ref = dcmplx(0.0020332632172573974)
     call test_one_GPL((/ 4 /),cmplx((/ 0 /)),cmplx(1.6),1,ref,'2.3')
     
-    ! ref = dcmplx(0.0020332632172573974)
-    ! call test_one_GPL((/ 1,1 /),cmplx((/ 1.7,0.0 /)),cmplx(1.1),2,ref,'2.4')
+    ref = dcmplx(0.0020332632172573974)
+    call test_one_GPL((/ 1,1 /),cmplx((/ 1.7,0.0 /)),cmplx(1.1),2,ref,'2.4')
 
-    ! ref = dcmplx(0.0020332632172573974)
-    ! call test_one_GPL((/ 1 /),(/(0.7,epsilon)/),(1.1,1.4),1,ref,'2.4')
   end subroutine do_GPL_tests
 
 END PROGRAM TEST

utils.f90

@@ -12,7 +12,6 @@
 MODULE utils
   implicit none
   integer, parameter :: prec = selected_real_kind(15,32)  
-  real, parameter :: zero = 1.0e-50
 
   ! logical :: print_enabled = .true.
   ! logical :: warnings_enabled = .true.
@@ -61,6 +60,19 @@ CONTAINS
     end do
   END FUNCTION get_flattened_z
 
+  FUNCTION find_amount_trailing_zeros(z) result(res)
+    complex(kind=prec) :: z(:)
+    integer :: res, i
+    res = 0
+    do i = size(z), 1, -1
+      if( z(i) == 0 ) then
+        res = res + 1
+      else
+        exit
+      end if
+    end do
+  END FUNCTION find_amount_trailing_zeros
+
   FUNCTION find_first_zero(v) result(res)
     ! returns index of first zero, or -1 if there is no zero
     integer :: v(:), i, res
@@ -119,33 +131,34 @@ END MODULE utils
 !   use  utils
 !   implicit none
 
-!   complex(kind=prec), dimension(3) :: a = cmplx((/1,2,3/))
-!   complex(kind=prec) :: z_flat(2)
-!   complex(kind=prec), allocatable :: z(:)
-!   integer :: m_prime(2), condensed_size
-!   integer, allocatable :: m(:)
-!   complex(kind=prec) :: b(size(a)+1,size(a)+1)
-
-!   ! ! test shuffling
-!   ! b = 1
-!   ! b = shuffle_with_zero(a)
-!   ! call print_as_matrix(b)
-
-!   ! test condensing
-!   z_flat = cmplx((/4,0/))
-!   m_prime = get_condensed_m(z_flat)
-!   if(find_first_zero(m_prime) == -1) then
-!     condensed_size = size(m_prime)
-!   else
-!     condensed_size = find_first_zero(m_prime)-1 
-!   end if
-!   allocate(m(condensed_size))
-!   allocate(z(condensed_size))
-!   m = m_prime(1:condensed_size)
-!   z = get_condensed_z(m,z_flat)
-!   z_flat = get_flattened_z(m,z)
-!   deallocate(m)
-!   deallocate(z)
+
+!   ! complex(kind=prec), dimension(5) :: a = cmplx((/1,2,3/))
+!   ! complex(kind=prec) :: z_flat(2)
+!   ! complex(kind=prec), allocatable :: z(:)
+!   ! integer :: m_prime(2), condensed_size
+!   ! integer, allocatable :: m(:)
+!   ! complex(kind=prec) :: b(size(a)+1,size(a)+1)
+
+!   ! ! ! test shuffling
+!   ! ! b = 1
+!   ! ! b = shuffle_with_zero(a)
+!   ! ! call print_as_matrix(b)
+
+!   ! ! test condensing
+!   ! z_flat = cmplx((/4,0/))
+!   ! m_prime = get_condensed_m(z_flat)
+!   ! if(find_first_zero(m_prime) == -1) then
+!   !   condensed_size = size(m_prime)
+!   ! else
+!   !   condensed_size = find_first_zero(m_prime)-1 
+!   ! end if
+!   ! allocate(m(condensed_size))
+!   ! allocate(z(condensed_size))
+!   ! m = m_prime(1:condensed_size)
+!   ! z = get_condensed_z(m,z_flat)
+!   ! z_flat = get_flattened_z(m,z)
+!   ! deallocate(m)
+!   ! deallocate(z)
 
 ! END  PROGRAM test