Appendix D: SAS PROC IML

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Appendix D SAS PROC IML

• Matrix Language with Interface to all SAS
  capacities and functionality
• Use it as a calculator
• Use it to write your own programs
• Full Documentation at http//support.sas.com/onlin
  edoc/913/docMainpage.jsp

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PROC IML Overview

• Invoke SAS from your machine, and type in
• proc iml
• Then click on the Run button. You are now ready
  to run the SAS matrix language. To input the 4
  by 2 matrix X, enter
• X 1 2,
• 3 4,
• 5 6,
• 7 9
• Using curly brackets with space to delimit
  columns and a comma to delimit rows.

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PROC IML Operators

• Transpose (key above the on US English
  keyboards)
• Addition
• Subtraction -
• Matrix Multiply
• Scalar Multiplication
• Inverse of matrix INV(matrix)
• Diagonal of matrix DIAG(matrix)
• Square Root of elements SQRT(matrix)
• Elementwise Division /

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PROC IML Matrix Subsets

• Subscript row(s), col(s)
• Pick off jth col of A A,j
• Sum across columns A,
• Subset A A1 3 2, 1
• The last example takes rows 1, 3 and 2 and column
  1 from A.