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diagonalMatrix(Matrix) -- make a diagonal matrix from entries of a matrix

Synopsis

Usage:
diagonalMatrix m
Function: diagonalMatrix
Inputs:
- m, a matrix
Outputs:
- a matrix, a diagonal matrix whose diagonal entries are the entries of m

Description

i1 : R = QQ[a..d];

i2 : diagonalMatrix vars R

o2 = | a 0 0 0 |
     | 0 b 0 0 |
     | 0 0 c 0 |
     | 0 0 0 d |

             4       4
o2 : Matrix R  <--- R

If the matrix has more than one row, the first column is placed on the diagonal first, then the second column, etc.

i3 : diagonalMatrix matrix{{0,2},{4,6}}

o3 = | 0 0 0 0 |
     | 0 4 0 0 |
     | 0 0 2 0 |
     | 0 0 0 6 |

              4        4
o3 : Matrix ZZ  <--- ZZ

See also

matrices