title: “sort” categories: sort command —
sort
The sort command creates a sort key for chosen node or element attributes. Sort can be in ascending or descending order and will not alter current mesh object values (though the line_graph option will create three new attributes; see below). One can perform a sort on a single attribute or in the case of index or rank sorting, one can perform a multikey sort. The line_graph sort does not sort on an attribute but instead sorts line segment elements into a reasonable order based on connectivity. In each case the sort key that is created can be used in the reorder command to change the node or element ordering of the mesh object.
SYNTAX for SINGLE KEY
sort / cmo_name / bins / [ ascending or descending ] / sort_key_name / sort_attribute / [epsilon_user]
SYNTAX for MULTIKEY
sort / cmo_name / index or rank / [ ascending or descending ] / sort_key_name / in_att1, in_att2, in_att3 ...
SYNTAX for LINE GRAPH
sort / cmo_name / line_graph / [ ascending or descending ] / sort_key_name / [ elements or nodes ]
The command parameters include the cmo_name, followed by the
sort_type. The ordering is indicated by ascending
or
descending
. A new attribute is created with the name given by sort_key.
For the bins
, index
, and rank
options, sorting is
performed on the sort_attributes which can be a single attribute name
or a list of attribute names. This list is formed with attribute names
in_att1, in_att2, through in_attn. The line_graph
option does
not take any attributes as arguments because it sorts based on the
connectivity of the elements, which must be line segments.
Command Options
cmo_name
is the name of a valid mesh object or def which selects the currently active mesh object.
sort_type
The sorting methods include bins
, index
, rank
and line_graph
See below.
bins
is a singlekey sort which assigns each in_att1 value a bin
number. If in_att1 is an integer then bins each have a unique integer
value associated with them. If in_att1 is a real number, bins are
created with values which are within +epsilon of each other, where
epsilon=1.e10 x abs(real_bin_value). If all array values are unique,
then the maximum value of the index array will equal the number of
entries in the sorted list. Otherwise, the maximum value of the index
array will be less than the number of entries in the sorted list but
will equal the number of unique entries in the list. With the bins
method, an optional user specified epsilon
multiplier, epsilon_user, will override the default value of 1.e10.
index
is a single or multikey sort that constructs an index table such that
in_att1(ikey(1)) is the first entry in the sorted array, in_att1(ikey(2)) is the second, etc.
rank
is a single or multikey sort that constructs a rank table such that the tables ith entry give the rank of the ith entry of the sorted arrays. The rank table is derived from the index table by:
foreach j = 1,N rank(index(j)) = j end
line_graph
is a sort for connected line segments for arranging into a reasonable order. The sorted order for components which are not polylines or polygons is unspecified, but it will usually be reasonable because the underlying
algorithm visits the edges via depth first search. In particular, it makes the following guarantees:
 Each connected component will be arranged together.
 Polylines (chains of line segments with no branching or loops) will be in order from one end to the other.
 Polygons will be in order starting from one segment and looping back around to the same place.
line_graph
with elements
generates the following three integer element attributes:
 cid: A component id for distinguishing separate connected components. Each connected component receives a unique positive integer starting from one. This allows you to identify all the edges in a particular component by selecting all elements with a particular component id.

ctype: The component type, represented as an integer from 1 to 5.
 1 (Polyline)
 A connected chain of segments with no branches or loops.
 2 (Tree)
 A connected acyclic component.
 3 (Polygon)
 A component consisting solely of a single loop.
 4 (Shared Edges)
 A component which has a pair of cycles with a shared edge.
 5 (Other)
 Anything which does not fit into the above categories.
 loop_id: This is a unique positive integer assigned to each simple cycle. Edges that are not part of a cycle receive a default value of zero. If an edge is shared (i.e. part of more than one cycle) then it will be labeled with only one of its cycles. In this case, the cycle corresponding to the label is not fully specified because there is more than one right answer.
line_graph
with nodes
is based on the option for
elements, except that it does not create extra attributes. Based on
the sorted elements, the nodes will be reordered in the same sequence.
This is necessary for triangulation as “TRIANGULATE” routine requires
the nodes to be in either clockwise or counterclockwise order.
ascending
or descending
is the sort_order to order the sort_attributes. The line_graph
sort will ignore this option, but it still expects the field to be present for consistency with the other sort variations.
sort_key_name
The name for an integer vector (VINT) which will hold the output sort key values. If the name exists it will be used. If no name is given for sort_key_name, a name will be created which will be the concatination
of ikey_ and the first attribute name in sort_attributes (i.e./def/imt will produce a sort key named ikey_imt). For the line_graph
option, the default key will be called ikey_line_graph.
sort_attributes
The name of one or more existing attribute names. Each attribute will be used as a node of element based array upon which the sorting routine will sort. Multikey sorts can have an arbitrary number
of input attributes. Attribute in_att1(n) has priority over in_att2(n) in breaking ties. Note: all attributes are put into a type real work array before being sent to the sort routine.
EXAMPLES
sort / cmo / line_graph / ascending / ikey / elements
Sort the line segment elements into a reasonable order based on connectivity. This also creates attributes cid, ctype, and loop_id (see above).
sort / cmo / index / ascending / ikey / imt zic yic xic
Multikey sort first by imt then to break ties consider z coordinate, then if there are further ties, use y coordinate. Use x coordinate as final tie breaker.
sort / cmo / rank / descending / ikey / yic
Produce ranking of nodes based on y coordinate in descending order.
sort / cmo / index /def/def/ xic yic zic
Produce index of noded coordinates. This would be like a line sweep sort where the sweep is first along x coordinate then y then z.
sort / cmo / bins / ascending / i_index / xic sort/ cmo / bins / ascending / j_index / yic sort / cmo / bins / ascending / k_index / zic
If the cmo were a finite difference grid of points, the above three commands would produce the finite difference indexing. All points with the same x value would be in the same i_index bin, all points with the same y value would be in the same j_index bin, etc.
define MOGOOD motet define MOSORT mopts cmo/addatt/MOSORT id_mesh1 /VINT/scalar/nnodes/linear/permanent//0 interpolate/voronoi/ MOSORT id_mesh1/1,0,0/ MOGOOD id_node cmo/addatt/MOSORT id_diff /VINT/scalar/nnodes/linear/permanent//0 math/sub/MOSORT id_diff/1,0,0/ MOSORT id_mesh1 /MOGOOD id_node cmo/printatt/MOSORT/ id_diff / minmax sort/ MOSORT/ index / ascending / ikey / id_mesh1 reorder/MOSORT/ ikey
Sort and reorder a set of nodes based on a source mesh, based on node id and position xyz. Use interpolate/voronoi
to associate each node with the good mesh node id’s. We check to see if the ordering for both mesh objects is different by subtracting the node id of one from the second. The result would be 0 for all nodes that match position and node id. Sort mesh object using the attribute with the interpolated node id’s, then reorder using the ikey values.
LINKS:
Example 1 for sort and reorder
Example 2 for sort and reorder
OLD FORMAT  No longer supported but syntax will still work.
sort / xyz / [ index bins rank ]
sort/xyz/index
sorts the x,y,z coordinate integer arrays i_index,
j_index, k_index such that xic(i_index(i)) i=1,..nnodes lists the coordinate in ascending order.
sort/xyz/bins
sorts the x,y,z coordinates and assigns each i_index,
j_index, k_index values in ascending order of the bin number of the sorted list.
sort/xyz/rank
sorts the x,y,z coordinates and assigns each i_index,
j_index, k_index values the ranking of the node in the sorted list.
If all array values are unique, then the maximum value of the index array will equal the number of entries in the sorted list. Otherwise, the maximum value of the index array will be less than the number of entries in the sorted list but will equal the number of unique entries in the list.
For example given x = 0, 1, 2, 1, 0 sort/xyz/index returns i_index = 5, 1, 4, 2, 3 sort/xyz/bins returns i_index = 1, 2, 3, 2, 1 sort/xyz/rank returns i_index = 2, 4, 5, 3, 1