Matrix Multiplication

Building Recommendation Engines with PySpark

Jamen Long

Data Scientist at Nike

Matrix Multiplication

two square matrices of same dimensions

Building Recommendation Engines with PySpark

Matrix Multiplication

two square matrices multipied to obtain third matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in first row of first matrix and first column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in first row of first matrix and first column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

product matrix with products added together

Building Recommendation Engines with PySpark

Matrix Multiplication

product matrix with only first cell filled in with value of 30

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in first row of first matrix and second column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in first row of first matrix and second column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in first row of first matrix and second column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

product matrix with second value of 24 filled in

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in first row of first matrix and third column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

product matrix with third value of 18 filled in

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in second row of first matrix and first column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in second row of first matrix and third column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in third row of first matrix and first column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in third row of first matrix and second column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

arrows pointing to values in third row of first matrix and third column of second matrix

Building Recommendation Engines with PySpark

Matrix Multiplication

two matrices with first matrix number of columns equal to second matrix number of rows

Building Recommendation Engines with PySpark

Matrix Multiplication

two matrices with first matrix columns not equal to second matrix rows

Building Recommendation Engines with PySpark

Let's practice!

Building Recommendation Engines with PySpark

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