# tritwise

Tritwise operations

```
var tritwise = require('tritwise');
```

Operates on each trit (base 3 digit) of the inputs, in balanced ternary notation.

The width of the "tryte" (analogous to byte) is set in `tritwise.tryte_size`

,
and defaults to 5 trits.

Unary (1-input) operations:

```
a NTI(a) STI(a) PTI(a) FD(a) RD(a)
i 1 1 1 0 i
0 i 0 1 0 0
1 i i i 1 0
```

Simple ternary inverter (STI) inverts 1/i and keeps 0, negative/positive ternary inverter (NTI and PTI) replace 0 with i or 1. FD and RD are forward and reverse diodes, only allowing 1 or i and replacing all others with 0. Other unary operations are possible but STI is the most analogous to binary (base 2) invert (NOT), in that it negates the sign of the value, and flips all the trits:

```
tritwise.STI(33); // -33
tritwise.STI(-33); // 33
tritwise.PTI(-8); // 119
tritwise.FD(107); // 108
```

Dyadic (2-input) operations:

```
TOR(a,b) prefers 1,0,i (maximum)
TAND(a,b) prefers i,0,1 (minimum)
BUT(a,b) prefers 0,i,1
```

TOR and TAND are comparable to binary base-2 OR and AND. Binary OR and AND "prefer" 1,0 or 0,1 from the bitwise inputs, respectively; similarly, TOR and TAND prefer 1,0,i or i,0,1, respectively. The output trits always match either of the two inputs. In situations where zero is preferred, the BUT function can be used to prefer 0,i,1.

References: Ternary computing Testebed: 3-Trit Computer Architecture, Appendix A, Section 4 "Dyadic Functions"