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Diffstat (limited to 'contrib/bc/scripts/sqrt_random.bc')
| -rw-r--r-- | contrib/bc/scripts/sqrt_random.bc | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/contrib/bc/scripts/sqrt_random.bc b/contrib/bc/scripts/sqrt_random.bc new file mode 100644 index 000000000000..1f58c2e30c5d --- /dev/null +++ b/contrib/bc/scripts/sqrt_random.bc @@ -0,0 +1,129 @@ +#! /usr/bin/bc +# +# SPDX-License-Identifier: BSD-2-Clause +# +# Copyright (c) 2018-2024 Gavin D. Howard and contributors. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are met: +# +# * Redistributions of source code must retain the above copyright notice, this +# list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright notice, +# this list of conditions and the following disclaimer in the documentation +# and/or other materials provided with the distribution. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE +# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +# POSSIBILITY OF SUCH DAMAGE. +# + +scale = 0 + +bits = rand() + +# This extracts a bit and takes it out of the original value. +# +# Here, I am getting a bit to say whether we should have a value that is less +# than 1. +bits = divmod(bits, 2, negpow[]) + +# Get a bit that will say whether the value should be an exact square. +bits = divmod(bits, 2, square[]) + +# See below. This is to help bias toward small numbers. +pow = 4 + +# I want to bias toward small numbers, so let's give a 50 percent chance to +# values below 16 or so. +bits = divmod(bits, 2, small[]) + +# Let's keep raising the power limit by 2^4 when the bit is zero. +while (!small[0]) +{ + pow += 4 + bits = divmod(bits, 2, small[]) +} + +limit = 2^pow + +# Okay, this is the starting number. +num = irand(limit) + 1 + +# Figure out if we should have (more) fractional digits. +bits = divmod(bits, 2, extra_digits[]) + +if (square[0]) +{ + # Okay, I lied. If we need a perfect square, square now. + num *= num + + # If we need extra digits, we need to multiply by an even power of 10. + if (extra_digits[0]) + { + extra = (irand(8) + 1) * 2 + } + else + { + extra = 0 + } + + # If we need a number less than 1, just take the inverse, which will still + # be a perfect square. + if (negpow[0]) + { + scale = length(num) + 5 + num = 1/num + scale = 0 + + num >>= extra + } + else + { + num <<= extra + } +} +else +{ + # Get this for later. + l = length(num) + + # If we need extra digits. + if (extra_digits[0]) + { + # Add up to 32 decimal places. + num += frand(irand(32) + 1) + } + + # If we need a value less than 1... + if (negpow[0]) + { + # Move right until the number is + num >>= l + } +} + +bits = divmod(bits, 2, zero_scale[]) + +# Do we want a zero scale? +if (zero_scale[0]) +{ + print "scale = 0\n" +} +else +{ + print "scale = 20\n" +} + +print "sqrt(", num, ")\n" + +halt |