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lect02

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lect02, Thu 01/09

Interesting matrices

• Lecture Files

Reading assignment

NCM Sections 2.1 through 2.6 (linear equations and Gaussian elimination).

References for today’s lecture

• numpy quickstart tutorial

• short video intro to numpy

Outline

• Review of course policies

• Matrices: The 2-by-2 example

• Matrices: Understanding Ax = b in the temperature problem

• Arrays in numpy
  • creating arrays
  • 1-dimensional, 2-dimensional, …
  • reshape
  • slicing arrays
  • fancy indexing of 2-d arrays
  • permuting rows or columns of 2-d arrays
• Matrix and vector arithmetic in numpy
  • matrix transpose
  • vector-vector and matrix-matrix addition
  • matrix-vector multiplication
  • matrix-matrix multiplication
• Interesting matrices:
  • identity matrix
  • diagonal matrix
  • permutation matrix (and permutation vectors)
  • triangular matrix
  • singular matrix, nonsingular matrix
  • inverse matrix
  • orthogonal matrix