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 multi-key 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 MULTI-KEY

 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 single-key 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.e-10 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.e-10.

index is a single or multi-key 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 multi-key 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:

line_graph with elements generates the following three integer element attributes:

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. Multi-key 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

Multi-key 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