mutable matrices

To and from matrices:
 i1 : m = matrix{{1,2,3},{4,5,6}} o1 = | 1 2 3 | | 4 5 6 | 2 3 o1 : Matrix ZZ <--- ZZ i2 : n = mutableMatrix m o2 = | 1 2 3 | | 4 5 6 | o2 : MutableMatrix i3 : m2 = matrix n o3 = | 1 2 3 | | 4 5 6 | 2 3 o3 : Matrix ZZ <--- ZZ i4 : m2 - m == 0 o4 = true
Modifying and accessing entries. Remember that the upper left entry is (0,0), not (1,1)!
 i5 : n_(0,0) = 212314323 o5 = 212314323 i6 : n_(0,0) o6 = 212314323 i7 : n o7 = | 212314323 2 3 | | 4 5 6 | o7 : MutableMatrix
Number of rows, columns, and the ring:
 i8 : numrows n o8 = 2 i9 : numColumns n o9 = 3 i10 : numcols n o10 = 3 i11 : ring n o11 = ZZ o11 : Ring

Some other methods for creating mutable matrices.

 i12 : mutableIdentity(RR_100,5) o12 = | 1 0 0 0 0 | | 0 1 0 0 0 | | 0 0 1 0 0 | | 0 0 0 1 0 | | 0 0 0 0 1 | o12 : MutableMatrix i13 : mutableMatrix(QQ,3,5) o13 = 0 o13 : MutableMatrix i14 : randomMutableMatrix(4,4,.5,100) o14 = | -35 0 0 0 | | 100 0 0 0 | | 0 0 82 18 | | -14 0 0 -98 | o14 : MutableMatrix