NCMatrix _ List -- Select some columns of an NCMatrix

Synopsis

Operator: _
Usage:

L = M_cols
Inputs:
- M, an instance of the type NCMatrix,
- cols, a list,
Outputs:
- L, an instance of the type NCMatrix,

Description

This command selects some columns of an NCMatrix.

i1 : A = QQ{a,b,c,d}

o1 = A

o1 : NCPolynomialRing

i2 : M = ncMatrix {{a,b,c,d},{b,c,d,a}}

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

o2 : NCMatrix

i3 : N = M || 2*M || -3*M

o3 = | a    b    c    d    |
     | b    c    d    a    |
     | 2*a  2*b  2*c  2*d  |
     | 2*b  2*c  2*d  2*a  |
     | -3*a -3*b -3*c -3*d |
     | -3*b -3*c -3*d -3*a |

o3 : NCMatrix

i4 : N_{0,2}

o4 = | a    c    |
     | b    d    |
     | 2*a  2*c  |
     | 2*b  2*d  |
     | -3*a -3*c |
     | -3*b -3*d |

o4 : NCMatrix

Ways to use this method:

NCMatrix _ List -- Select some columns of an NCMatrix