Loop identification -IX

The last circuit was short of one node because of an error in the node_checking function.

Here is the function:

	# A node is defined as a junction of 3 or more branches.
	def node_checking(x_mat, x_list, row, col, x_row, x_col):
	if ((row==0 and col==0) or (row==x_row-1 and col==x_col-1) or \
	(row==0 and col==x_col-1) or (row==x_row-1 and col==0)):
	# If its a corner point it can't be a node.
	# This prevents array index going out of range.
	pass
	# The next cases, can't be outer edges or corner points.
	else:
	if (row==0):
	# If it is the first row,
	# check if the element in the next and
	# previous columns and same row are connected.
	if not (x_mat[row][col+1]=='' or x_mat[row][col-1]==''):
	# Then check if the element in next row and
	# same column is connected. Look for a T junction.
	if not (x_mat[row+1][col]==''):
	x_list.append([row, col])
	if (row==x_row-1):
	# If it is the last row,
	# check if the elements in the next and
	# previous columns and same row are connected.
	if not (x_mat[row][col+1]=='' or x_mat[row][col-1]==''):
	if not (x_mat[row-1][col]==''):
	# Then check if element in the previous row and
	# same column is connected. Look for a T junction.
	x_list.append([row, col])
	if (col==0):
	# If it is the first column,
	# check if the element in the next column and
	# same row is connected.
	if not (x_mat[row][col+1]==''):
	# Then check if the elements in next and
	# previous row and same column are connected.
	# Look for a T junction.
	if not (x_mat[row+1][col]=='' or x_mat[row-1][col]==''):
	x_list.append([row, col])
	if (col==x_col-1):
	# If it is the last column,
	# check if the element in the previous column and
	# same row is connected.
	if not (x_mat[row][col-1]==''):
	# Then check if the elements in next and
	# previous row and same column are connected.
	# Look for a T junction.
	if not (x_mat[row+1][col]=='' or x_mat[row-1][col]==''):
	x_list.append([row, col])
	if (row>0 and row<x_row-1 and col>0 and col<x_col-1):
	# If the element is not on the outer boundary
	if (x_mat[row][col+1]!='' and x_mat[row][col-1]!=''):
	# Check if the elements in next and
	# previous columns and same row are connected
	if (x_mat[row+1][col]!='' or x_mat[row-1][col]!=''):
	# Then check if elements in either the next and
	# previous row and same column are connected
	x_list.append([row, col])
	elif (x_mat[row+1][col]!='' and x_mat[row-1][col]!=''):
	# Check if the elements in next and
	# previous rows and same column are connected
	if (x_mat[row][col+1]!='' or x_mat[row][col-1]!=''):
	# Then check if elements in either the next and
	# previous column and same row are connected
	x_list.append([row, col])

view raw node_def.py hosted with ❤ by GitHub

The difference is caused by the last block:

if (row>0 and row<x_row-1 and col>0 and col<x_col-1):
    # If the element is not on the outer boundary
    if (x_mat[row][col+1]!='' and x_mat[row][col-1]!=''):
        # Check if the elements in next and
        # previous columns and same row are connected
        if (x_mat[row+1][col]!='' or x_mat[row-1][col]!=''):
            # Then check if elements in either the next and
            # previous row and same column are connected
            x_list.append([row, col])
    elif (x_mat[row+1][col]!='' and x_mat[row-1][col]!=''):
        # Check if the elements in next and
        # previous rows and same column are connected
        if (x_mat[row][col+1]!='' or x_mat[row][col-1]!=''):
            # Then check if elements in either the next and
            # previous column and same row are connected
            x_list.append([row, col])
The second elif statement had an extra indent!