## table of contents

MATHO-PRIMES(1) | Mathomatic Utilities | MATHO-PRIMES(1) |

# NAME¶

matho-primes - generate consecutive prime numbers

# SYNOPSIS¶

**matho-primes** [start [stop] or "all"]
["twin"] ["pal" [base]]

**matho-primes** [-htuv] [-c count] [-m number] [-p base] [start
[stop]]

# DESCRIPTION¶

This command-line utility is optionally part of the mathomatic(1) package. It quickly computes any number of consecutive prime numbers using a windowing, memory efficient sieve of Eratosthenes algorithm, dumping them to standard output. They are displayed one prime per line in ascending order, unless the "twin" option is specified, which displays only twin primes, two primes per line.

Generates up to 18 decimal digit primes, or whatever is the number
of digits of precision for a floating point **long double** in the C
compiler used to compile this utility. Note that this utility might be
compiled to use only double precision floating point, if long double
precision is not fully supported by the C compiler or hardware, allowing at
most 15 decimal digit primes in that case.

Ways to verify that this utility is working are to pipe the output
into the Unix "factor" utility, or compare the output with the BSD
Games "primes" utility, using the supplied shell script:
**examples/testprimes.**

All numbers displayed by this utility are decimal (base 10) prime numbers. A prime number is an integer that cannot be factored.

A range may be specified on the command line, otherwise the
starting number and the number of primes to output is prompted for. The
range is **start** to **stop** inclusive, and **stop** must be
greater than or equal to **start.**

If the **-c** option is specified, the number of lines of
primes displayed is limited to the decimal count that follows this
option.

If the **-t** or "twin" option is specified on the
command line, only **twin primes** will be displayed. Twin primes are two
primes that differ in value by 2. Each twin pair is displayed together on
the same line separated by a space character.

If the **-p** or "pal" option is specified on the
command line, only **palindromic primes** are displayed. Palindromes are
symmetrical, they read exactly the same forward and backward. The
palindromic number **base** may be specified, the default is base 10. The
**base** can be any integer greater than 1. Primes are always displayed
in decimal (base 10).

The version number and short help on the allowed command-line
parameters and usage information are displayed when given the **-h**
option.

With the **-u** option, all output (standard output and
standard error output) is set to be unbuffered, making all output happen
immediately, instead of when the output buffer is full or when the program
terminates or waits for input.

The **-m** option changes the memory size of the prime number
sieve window. It is followed by a decimal, floating point number which is a
multiplier of the default window size (2 megabytes). It is possible that
changing the memory size may speed up the total run time a bit; otherwise
there is no reason to use this option, and its use is not recommended.

The **-v** option simply displays the program name and version
number, and then exits successfully.

# AUTHOR¶

George Gesslein II (gesslein@mathomatic.org) at "http://www.mathomatic.org".

# REPORTING BUGS¶

If you find a bug, please report it to the author or at "https://launchpad.net/mathomatic".

# SEE ALSO¶

rmath(1), mathomatic(1), primorial(1), matho-mult(1), matho-sum(1), matho-pascal(1), matho-sumsq(1)

Mathomatic |