NISSY(1) General Commands Manual NISSY(1)

NAME

nissy — a Rubik’s cube solver and FMC assistant

SYNOPSIS

nissy [−b]
nissy command [options...]

DESCRIPTION

nissy is a Rubik’s Cube solver. It uses techniques from Herbert Kociemba’s Cube Explorer and Tomas Rokicki’s nxopt. With 4 cores at 2.5GHz and using about 3Gb of RAM, Nissy can find the optimal solution for a random Rubik’s cube position in about a minute on average. Nissy can also solve different substeps of the Thistlethwaite’s algorithm and more.

When run without any argument an interactive shell is launched, otherwise the provided command is executed and nissy terminates. If the option −b is given, every argument after it is ignored and the shell is launched without any prompt or welcome message. This can be used to run nissy in batch mode, for example writing a list of commands in a file (one per line) and running nissy -b < file

The commands that can be run in the interactive shell are the same that can be run non-interactively and are provided below.

COMMANDS

The available commands are the following:

cleanup scramble

Rewrites the given scramble using only the 18 base (HTM) moves and at most two rotations at the end. If Ar scramble uses NISS, all moves done on normal scramble are written first, followed by all moves done on inverse.

commands

List all available commands.

freemem

Release some large tables from memory. You can use this command in case you want to keep nissy open without using too much RAM.

gen [−t N]

Generate all tables used by nissy. Run this to complete your installation. If N is specified, N CPU threads will be used (defaults to 64, use less only if you don’t want nissy to use all of your CPU resources).

help [command]

Display help. If no command is given, a generic help message is printed, otherwise a specific help relative to command is returned.

invert scramble

Invert the given scramble.

print scramble

Display a text-only description of the cube obtained after applying scramble.

quit

Quit nissy.

scramble [
−n N] [
type]

Print a randomly-generated (random position) scramble If N is given, it produces N scrambles. type can be specified to be one of the following:

corners

Scramble with solved edges (only cornes are scrambled).

dr

Scramble with solved DR on U/D.

edges

Scramble with solved corners (only edges are scrambled).

eo

Scramble with solved EO on F/B axis.

fmc

Scramble the full cube and the resulting scramble starts and ends with the moves R' U' F.

htr

Scramble with HTR solved.

solve step [
options] scramble

Solve the given step on the given scramble. By default it finds only one (shortest) solution, without using niss, and it displays the number of moves at the end of the line. The options for the solve command are the following:

−a

Print all solutions: some solutions are filtered out by default for some steps, for examples EOs that finish with F', with this options they are not.

−c

Display only the number of solutions found, not the solutions themselves.

−m min

Only look for solution that are at least min moves long.

−M MAX

Only look for solution that are at most MAX moves long.

−n N

Try to find N solutions. By default and unless the −M or −o options are used, at most one solution is returned. If at least one of −M and −o is used, all the solutions found within the given bounds are returned. The option −s overwrites these default behaviors and at most N solutions are returned, still satisfiyng the other constraints.

−N

Allow use of NISS.

−o

Only find solutions that require the minimum number of moves.

−O N

Only find solutions that require at most N moves more than the optimal solution. If N is 0, this is equivalent to −o

−p

Plain style: do not print the number of moves.

−t N

Use N CPU threads. By default nissy uses only 1 thread. Using more than one thread will improve performance, but the optimal number depends on your machine and operating system. Generally, using one less than the number of threads of your CPU works quite well.

−v

Verbose mode: print some information during the search and print each solution as it is found instead of only printing them all together at the end.

steps

List all available steps for the solve command.

twophase scramble

Find a solution using a two-phase method. This does not guarantee to return an optimal solution (and in fact most often it does not), but it is very fast.

unniss scramble

Rewrite the scramble without using NISS.

version

Display version information.

SCRAMBLES

All the commands above that accept a scramble also accept a −i option with no arguments. If this option is given, multiple scrambles are read from standard input (one per line) until and EOF is found, at which point stdin is cleared.

ENVIRONMENT

Data is stored in the folder pointed to by $NISSYDATA. If that variable is unset the folder $XDG_DATA_HOME/nissy or $HOME/.nissy is used instead. If none of this environment variables is defined (e.g. in a non-UNIX system), the current folder is used.

EXAMPLES

The command:

nissy solve -v -O 1 "R'U'FD2L2FR2U2R2BD2LB2D'B2L'R'BD2BU2LU2R'U'F"

Returns:

Searching depth 0
Searching depth 1
(some more lines)
Searching depth 16
D2 F' U2 D2 F' L2 D R2 D F B2 R' L2 F' U' D
Searching depth 17
D2 F' U2 D2 F' L2 D R2 D F B2 R' L2 F' U' D (16)

Notice that the solution is printed twice: the first time it is printed as soon as it is found as requested by the -v option.

The command:

nissy solve eofb -m 4 -M 5 -N -n 6 "R'U'FD2L2 FR2 U2R2BD2 L B2 D' B2 L' R'"

Returns:

U B U' B (4)
U (B R' B) (4)
(U B R' B) (4)
U2 F R2 F (4)
U2 B U2 B (4)
(U2 B R' B) (4)

On a UNIX shell, the composite command

nissy scramble -n 2 | nissy solve -i > file.txt

Generates two random scrambles, solves them and saves the result to file.txt. The file will look something like this:

>>> Line: D U2 F D B' F L2 D' F2 R2 L B2 L' U2 B2 R F2 L' D2
U2 R2 F2 L B2 D' R2 D' F U L2 B' U' R2 D2 R2 U (17)
>>> Line: D B R U' B' L2 U L U D2 R L B2 U2 L2 U2 R U2 B2 L F2
D' F R' D B L2 B R2 L U L U2 B D' U R U F2 (18)

AUTHORS

Sebastiano Tronto <sebastiano@tronto.net>

SOURCE CODE

Source code is available at https://nissy.tronto.net GNU November 2021 NISSY(1)