SmallBASIC Guide

Arrays and Matrices

Define a 3x2 matrix

A = [11, 12; 21, 22; 31, 32]

That creates the array

| 11  12 |
| 21  22 | = A
| 31  32 |

The comma used to separate column items; the semi-colon used to separate rows. Values between columns can be omitted.

A = [ ; ; 1, 2 ; 3, 4, 5]

This creates the array

| 0  0  0 |
| 1  2  0 | = A
| 3  4  5 |

Supported operators: Add/sub:

B = [1, 2; 3, 4]: C = [5, 6; 7, 8]

A = B + C
C = A - B

Equal:

bool=(A=B)

Unary:

A2 = -A

Multiplication:

A = [1, 2; 3, 4]: B = [5 ; 6]
C = A * B
D = 0.8 * A

Inverse:

A = [ 1, -1, 1; 2, -1, 2; 3, 2, -1]
? INVERSE(A)

Gauss-Jordan:

? "Solve this:"
? "  5x - 2y + 3z = -2"
? " -2x + 7y + 5z =  7"
? "  3x + 5y + 6z =  9"
?
A = [ 5, -2, 3; -2, 7, 5; 3, 5, 6]
B = [ -2; 7; 9]
C = LinEqn(A, B)
? "[x;y;z] = "; C

There is a problem with 1 dimension arrays, because 1-dim arrays does not specify how SmallBASIC must see them.

DIM A(3)

| 1 2 3 | = A

or

| 1 |
| 2 | = A
| 3 |

And because this is not the same thing. (ex. for multiplication) So the default is columns

DIM A(3) ' or A(1,3)

| 1 2 3 | = A

For vertical arrays you must declare it as 2-dim arrays Nx1

DIM A(3,1)

| 1 |
| 2 | = A
| 3 |

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