sennajox

测试磁盘IO性能的几种方法
在磁盘测试中最关心的几个指标分别为:iops(每秒执行的IO次数)、bw（带宽，每秒的吞吐量）、lat（每次IO操作的延迟）。
当每次IO操作的block较小时，如512bytes/4k/8k等，测试的主要是iops。
当每次IO操作的block较大时，如256k/512k/1M等，测试的主要是bw。

1. 最简单的dd
dd是linux自带的磁盘读写工具，可用于测试顺序读写。
一般而言，磁盘读写有两种方式：BufferIO、DirectIO，DirectIO可以更好的了解纯磁盘读写的性能。

1.1 dd测试DirectIO

qnighy

Require Import Overture PathGroupoids Equivalences Trunc HProp HSet.
Require Import types.Unit types.Paths types.Sigma types.Forall types.Arrow.
Require Import types.Bool types.Universe Misc.
Require Import hit.Circle.
Local Open Scope path_scope.
Local Open Scope equiv_scope.

Instance isequiv_negb' : @IsEquiv@{Type Type} Bool Bool negb.
Proof.
    refine (@BuildIsEquiv

StuartGordonReid

def matrix_rank(self, bin_data: str, q=32):
    """
    Note that this description is taken from the NIST documentation [1]
    [1] http://csrc.nist.gov/publications/nistpubs/800-22-rev1a/SP800-22rev1a.pdf

    The focus of the test is the rank of disjoint sub-matrices of the entire sequence. The purpose of this test is
    to check for linear dependence among fixed length sub strings of the original sequence. Note that this test
    also appears in the DIEHARD battery of tests.

    :param bin_data: a binary string

StuartGordonReid

class BinaryMatrix:
    def __init__(self, matrix, rows, cols):
        """
        This class contains the algorithm specified in the NIST suite for computing the **binary rank** of a matrix.
        :param matrix: the matrix we want to compute the rank for
        :param rows: the number of rows
        :param cols: the number of columns
        :return: a BinaryMatrix object
        """
        self.M = rows

StuartGordonReid

def approximate_entropy(self, bin_data: str, pattern_length=10):
    """
    Note that this description is taken from the NIST documentation [1]
    [1] http://csrc.nist.gov/publications/nistpubs/800-22-rev1a/SP800-22rev1a.pdf

    As with the Serial test of Section 2.11, the focus of this test is the frequency of all possible overlapping
    m-bit patterns across the entire sequence. The purpose of the test is to compare the frequency of overlapping
    blocks of two consecutive/adjacent lengths (m and m+1) against the expected result for a random sequence.

    :param bin_data: a binary string

delta2323

#!/usr/bin/env python                                                                                                                                                                                              

import numpy
import six
from matplotlib import pyplot


seed = 0
N = 100
M = 10

ArdWar

clear all; clc
% SHELL CONSTANTS %

C = 0.5561613; % PENETRATION
a = 9.81; % GRAVITY
T_0 = 288; % TEMPERATURE AT SEA LEVEL
L = 0.0065; % TEMPERATURE LAPSE RATE
p_0 = 101325; % PRESSURE AT SEA LEVEL
R = 8.31447; % UNIV GAS CONSTANT
M = 0.0289644; % MOLAR MASS OF AIR

jw3126

# https://math.stackexchange.com/questions/1049788/haar-measure-of-an-angle-distance-ball-in-so3

using StatsBase
using LinearAlgebra
using StatPlots
using Plots
using Rotations

function sample_angles(N)
    map(1:N) do _

rmnshelest

https://abooij.github.io/wiwikwlhott/

• univalence axiom
• higher inductive types

"Both ideas are impossible to capture directly in classical set-theoretic foundations, but when combined in homotopy type theory, they permit an entirely new kind of "logic of homotopy types"." p13

invariance, homotopy

univalence foundations

kailaix

# solve 1D wave equation with ABC
using PyPlot
using Plots
using LinearAlgebra


N = 100
x = LinRange(-1.,1.,N+1)
Δx = x[2]-x[1]
NT = 200