config-fermat.sh

#!/bin/bash

# Shell script for generating fermat.cfg; Mlucas output saved to config-fermat.log

################################################################################
#                                                                              #
#   (C) 2024 by Catherine Cowie and Teal Dulcet.                               #
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#  This program is free software; you can redistribute it and/or modify it     #
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# Mlucas
MLUCAS=./Mlucas

# Number of iterations (use 100, 1000, or 10000 to match pre-computed values)
ITERS=100

# Minimum Fermat number (15 or greater)
MIN=15

# Maximum Fermat number (33 or less)
MAX=29

# Mlucas arguments
ARGS=(
	"$@"
	# Add desired -cpu or -core settings here, or as following arguments, e.g. bash ../config-fermat.sh -cpu 0:3
)

# First, tiny FFT lengths for F15 to F17 (note 4K is the smallest workable length without fiddly radix settings);
FFTS=([2]=15 [4]=16 [7]=17 [8]=17)
# Then, from small up to egregiously large FFTs for F18 to F33.
# The largest FFT reached is 512M, if MAX is set to 33.
# Note that large FFTs require considerable runtime at 10000 iterations.
for ((n = 0; n < 16; ++n)); do
	m=$((1 << n))
	f=$((18 + n))
	for k in 15 16; do
		if [[ $k -eq 15 && $n -lt 11 ]]; then
			# k = 7 multiples (7K, 14K, ...) become unworkable after F28 (14M).
			FFTS[14 * m]=$f
		fi
		# k = 15, 16 should both be supported up to at least F32.
		FFTS[k * m]=$f
		if [[ $k -eq 15 && $n -gt 5 ]]; then
			# k = 63 is mostly supported for F24 (1008K) and above.
			FFTS[63 * m >> 2]=$f
		fi
	done
done
for fft in "${!FFTS[@]}"; do
	f=${FFTS[fft]}
	if [[ -n $MIN && $f -lt $MIN ]]; then
		continue
	elif [[ -n $MAX && $f -gt $MAX ]]; then
		break
	fi
	printf '\n\tTesting F%s (2^%s + 1),\tFFT length: %sK\n\n' "$f" $((1 << f)) "$fft"
	args=("${ARGS[@]}")
	# First we test the very fiddly F15 and then loop over F16 up to maximum
	if [[ $f -eq 15 ]]; then
		args+=(-radset 8,8,16)
	fi
	if [[ $f -le 17 || $f -ge 32 ]]; then
		args+=(-shift 0)
	fi
	time $MLUCAS -f "$f" -fft "$fft" -iters $ITERS "${args[@]}" 2>&1 | tee -a config-fermat.log | grep -i 'error\|warn\|assert\|writing\|pmax_rec\|fft radices'
done