1. Module 2
Array Parameters

2. 2. Array Parameters
Array Parameters are parameters that can take on multiple values.
They can be 1-D, 2-D, or 3-D.
1-D: m rows x 1 column
2-D: m rows x n columns
3-D: m rows x n columns x k planes
17.1
-47.6
-5.2
25.0
107.9
AA =
BB =
CC =
5x1 array
5x3 array
mxnx3 array
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3. ...Array Parameters
In this chapter, we will discuss how to define array parameters and how to perform operations among them.
Topics covered:
A. Types of Array Parameters
B. How to Define
C. Retrieving Database Information
D. Array Operations
E. Workshop
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4. Array Parameters A. Types of Array Parameters
There are three types of array parameters:
Array
Table
Character
Type array is a standard 1-D, 2-D, or 3-D matrix of numeric values, such as BB shown here.
BB(2,3) = 704
BB(3,1) = 1033
etc.
5x3 array
BB =
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5. Array Parameters ...Types of Array Parameters
Type table is similar to array, except that its row, column, and plane indices can be real numbers, allowing you to interpolate values.
Requires the “zeroth” row, column, and plane to be filled with numbers.
Useful to define time-dependent loads and other similar functions.
Primary variables include X, Y, Z, temperature, velocity, pressure and time.
For example, the table array FORCE could represent a force-vs-time function, with the zeroth column representing time values.
FORCE(0.4) =
FORCE(6.5) = 560.0
FORCE(8.9) =
etc.
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6. Array Parameters ...Types of Array Parameters
A character array is a 1-D, 2-D, or 3-D matrix of alphanumeric strings.
Useful for storing file names, DOF labels, etc.
Each string can have up to eight characters.
JOB1
JOB2
JOB3
JOB4
JOB5 UX UY UZ
ROTY
ROTZ
jobs =
dofs =
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7. Array Parameters B. How to Define
Two steps to define an array parameter:
1. Specify name, type and dimension.
Utility Menu > Parameters > Array Parameters > Define/Edit > Add
or *DIM command. Example:
*dim,aa,array,4 ! 4x1x1 array
*dim,force,table,5 ! 5x1x1 table
*dim,bb,array,5,3 ! 5x3x1 array
*dim,dofs,char,6 ! 6x1x1 character array
parameter name can not exceed 32 characters
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8. Array Parameters ...How to Define
2. Fill in the array values.
Utility Menu > Parameters > Array Parameters > Define/Edit > Edit
Or *VEDIT command
Or “=”command. Example:
bb(1,1)=11,21,31,41,51
bb(1,2)=12,22,32,42,52
bb(1,3)=13,23,33,43,53
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9. Array Parameters ...How to Define
For table type arrays, you must fill in values for the zeroth locations. Otherwise, their values will default to the “tiny” number E-31.
For example:
force(1,1)=0,560,560,238.5,0
force(1,0)=1E-6,0.8,7.2,8.5,9.3
force(0,1)=0
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10. Array Parameters ...How to Define
For character arrays, there is no graphical way to fill in the strings.
Use the “=”command to type in the values, then use *STAT to list them.
Each string must be enclosed in single quotes.
Example:
dofs(1) = ‘ux’, ‘uy’, ‘uz’, ‘rotx’, ‘roty’, ‘rotz’
*stat,dofs
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11. Array Parameters ...How to Define
There are many other ways to fill arrays:
Predefined functions in *VFILL command (Utility Menu > Parameters > Array Parameters > Fill)
ramp function
random function
etc.
Read data from a file:
*VREAD for arrays
*TREAD for tables
Or Utility Menu > Parameters > Read from File
Retrieve data from the database (discussed next).
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12. Array Parameters C. Retrieving Database Information
Just as *GET retrieves scalar data from the database, you can use *VGET to retrieve array information.
Or Utility Menu > Parameters > Get Array Data
First dimension the array, then retrieve the data.
Example:
*dim,dispval,array,20,3 ! 20x3 array
*vget,dispval(1,1),node,1,u,x ! UX of nodes 1-20 in column 1
*vget,dispval(1,2),node,1,u,y ! UY in column 2
*vget,dispval(1,3),node,1,u,z ! UZ in column 3
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13. Array Parameters …Retrieving Database Information
Other types of array information you can retrieve:
nodal and keypoint coordinates (in the active CSYS)
attributes of elements, volumes, areas, etc.
select status of entities (1 if selected, 0 if not selected)
nodal stresses, strains, thermal gradients, thermal flux, etc.
element table data
and so on…
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14. Array Parameters D. Array Operations
Once you have defined array parameters, you can perform a variety of operations among them.
Utility Menu > Parameters > Array Operations
Or *VFUN, *VOPER, *VSCFUN, *VWRITE, etc.
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15. Array Parameters ...Array Operations
*VFUN operates on a single array parameter.
*vfun,b(1),sin,a(1) will result in b(j)=sin(a(j))
Other operations include:
natural log, common log, exponential
Square root, sort, copy
Conversion from local to global coordinates and vice-versa
Tangent and normal vectors to a path
etc.
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16. Array Parameters ...Array Operations
*VOPER operates on two array parameters.
*voper,c(1),a(1),sub,b(1) will result in c(k)=a(k)-b(k)
Other operations include:
addition, subtraction, multiplication, division
min, max, logical operations
derivatives, integrals
dot and cross products
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17. Array Parameters ...Array Operations
*VSCFUN determines properties of an array parameter.
*vscfun,maxval,max,a(1) will result in a scalar parameter maxval = max(a(i))
Other operations include:
sum of all the elements of an array
statistical quantities such as mean, median, standard deviation, variance and rms
min/max, index location of min/max
index locations of first and last non-zero entry
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18. Array Parameters ...Array Operations
*VWRITE writes data to a file in a formatted sequence.
Utility Menu > Parameters > Array Parameters > Write to File
Example:
*cfopen,wing,dat
*vwrite
(/,3x,’Node Number’,4x,’Temperature’,/)
*vwrite,nnum(1),tval(1)
(5x,f6.0,6x,e14.8)
*cfclose
will create a file called wing.dat with the nnum and tval arrays written in specified format.
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19. Array Parameters ...Array Operations
There are many, many more array operations available.
Please refer to your APDL Programmer’s Guide for details.
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20. Array Parameters E. Workshop
Refer to your Workshop Supplement for instructions on:
W1. Axisymmetric Wheel
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