I am trying to use julai as main language for my work. But I find that this plot is different than python (Which outputs the right plot)
Here is the python code and output
import numpy as np
import math
import matplotlib.pyplot as plt
u = 9.27*10**(-21)
k = 1.38*10**(-16)
j2 = 7/2
nrr = 780
h = 1000
na = 6*10**(23)
rho = 7.842
mgd = 157.25
a = mgd
d = na*rho*u/a
m_f = []
igd = 7.0
for t in range(1,401):
while True:
h1 = h+d*nrr*igd
x2 = (7*u*h1)/(k*t)
x4 = 2*j2
q2 = (x4+1)/x4
m = abs(7*(q2*math.tanh(q2*x2)**-1 - (1/x4)*math.tanh(x2/x4)**-1))
if abs(m - igd) < 10**(-12):
break
else:
igd = m
m_f.append(abs(m))
plt.plot(range(1,401), m_f)
plt.savefig("Py_plot.pdf")
and it gives the following right plot
The right plot as expected
But when I do the same calculations in julia it gives different output than python, here is my julia code
using Plots
u = 9.27*10^(-21)
k = 1.38*10^(-16)
j2 = 7/2
nrr = 780
h = 1000
na = 6*10^(23)
rho = 7.842
mgd = 157.25
a = mgd
d = na*rho*u/a
igd = 7.0
m = 0.0
m_f = Float64[]
for t in 1:400
while true
h1 = h+d*nrr*igd
x2 = (7*u*h1)/(k*t)
x4 = 2*j2
q2 = (x4+1)/x4
m = 7*(q2*coth(rad2deg(q2*x2))-(1/x4)*coth(rad2deg(x2/x4)))
if abs(abs(m)-igd) < 10^(-10)
break
else
igd = m
end
end
push!(m_f, abs(m))
end
plot(1:400, m_f)
and this is the unexpected julia output
unexpected wrong output from julia
I wish for help....
Code:
using Plots
const u = 9.27e-21
const k = 1.38e-16
const j2 = 7/2
const nrr = 780
const h = 1000
const na = 6.0e23
const rho = 7.842
const mgd = 157.25
const a = mgd
const d = na*rho*u/a
function plot_graph()
igd = 7.0
m = 0.0
trange = 1:400
m_f = Vector{Float64}(undef, length(trange))
for t in trange
while true
h1 = h+d*nrr*igd
x2 = (7*u*h1)/(k*t)
x4 = 2*j2
q2 = (x4+1)/x4
m = abs(7*(q2*coth(q2*x2)-(1/x4)*coth(x2/x4)))
if isapprox(m, igd, atol = 10^(-10))
break
else
igd = m
end
end
m_f[t] = m
end
plot(trange, m_f)
end
Plot:
Changes for correctness:
Changed na = 6.0*10^(23) to na = 6.0e23.
Since ^ has a higher precedence than *, 10^23 is evaluated first, and since the operands are Int values, the result is also an Int. However, Int (i.e. Int64) can only hold numbers up to approximately 9 * 10^18, so 10^23 overflows and gives a wrong result.
julia> 10^18
1000000000000000000
julia> 10^19 #overflow starts here
-8446744073709551616
julia> 10^23 #and gives a wrong value here too
200376420520689664
6.0e23 avoids this problem by directly using the scientific e-notation to create a literal Float64 value (Float64 can hold this value without overflowing).
Removed the rad2deg calls when calling coth. Julia trigonometric functions by default take radians, so there's no need to make this conversion.
Other changes
Marked all the constants as const, and moved the rest of the code into a function. See Performance tip: Avoid non-constant global variables
Changed the abs(m - igd) < 10^-10 to isapprox(m, igd, atol = 10^-10) which performs basically the same check, but is clearer and more flexible (for eg. if you wanted to change to a relative tolerance rtol later).
Stored the 1:400 as a named variable trange. This is just because it's used multiple times, so it's easier to manage as a variable.
Changed m_f = Float64[] to m_f = Vector{Float64}(undef, length(trange)) (and the push! at the end to an assignment). If the size of the array is known beforehand (as it is in this case), it's better for performance to pre-allocate it with undef values and then assign to it.
Changed u and k also to use the scientific e-notation, for consistency and clarity (thanks to #DNF for suggesting the use of this notation in the comments).
I found this algorithm:
sem empty = 1;
sem full = 0;
public void send() {
P(empty)
<<inserting data>>
V(full)
}
public T receive(){
T data;
P(full)
<<data = extract()>>
V(empty);
return data;
}
To demonstrate that it is deadlock-free, the author of the book has wrote this demonstration:
-Hypothesis for absurd:
𝑣𝑎𝑙(𝑒𝑚𝑝𝑡𝑦, 𝑡) = 0 → 𝑛𝑝(𝑒𝑚𝑝𝑡𝑦, 𝑡) = 𝑛𝑣(𝑒𝑚𝑝𝑡𝑦, 𝑡) + 1
𝑣𝑎𝑙(𝑓𝑢𝑙𝑙, 𝑡) = 0 → 𝑛𝑝(𝑓𝑢𝑙𝑙, 𝑡) = 𝑛𝑣(𝑓𝑢𝑙𝑙, 𝑡)
-Then we can say that:
𝑛𝑝(𝑒𝑚𝑝𝑡𝑦, 𝑡) = 𝑛𝑣(𝑒𝑚𝑝𝑡𝑦, 𝑡) + 1 = 𝑛𝑝(𝑓𝑢𝑙𝑙) + 1 = 𝑛𝑝(𝑓𝑢𝑙𝑙) + 1 = 𝑛𝑝(𝑒𝑚𝑝𝑡𝑦) + 1 → 𝑛𝑝(𝑒𝑚𝑝𝑡𝑦) = 𝑛𝑝(𝑒𝑚𝑝𝑡𝑦) + 1 → 0 = 1.
Can you help me understand why he repeated the line 𝑛𝑝(𝑓𝑢𝑙𝑙) + 1 = 𝑛𝑝(𝑓𝑢𝑙𝑙) + 1? Is it an error or does it have substituted something that didn't affect the value?
If the value of the semaphore full would have been more than 0, should he had to put a different value than +1?
Here is my sphinx search configuration (sphinxsearch_0.9.9-6_amd64):
index FULL
{
charset_type = utf-8
source = FULL
path = /var/sphinx/data/Full
docinfo = extern
mlock = 0
min_stemming_len = 1
min_prefix_len = 1
min_word_len = 1
html_strip = 1
index_exact_words = 1
}
searchd
{
listen = 192.168.2.3
log = /var/log/sphinxsearch/searchd.log
query_log = /var/log/sphinxsearch/query.log
read_timeout = 3
client_timeout = 60
max_children = 30
pid_file = /var/run/searchd.pid
max_matches = 1000
seamless_rotate = 1
preopen_indexes = 0
unlink_old = 1
mva_updates_pool = 1M
max_packet_size = 8M
max_filters = 256
max_filter_values = 4096
}
I use php as client
$sphinx_client->SetServer('localhost', 9312);
$sphinx_client->SetConnectTimeout(1);
$sphinx_client->SetArrayResult(true);
$sphinx_client->setRankingMode(SPH_RANK_WORDCOUNT);
$sphinx_client->SetMatchMode(SPH_MATCH_EXTENDED2);
if ($mode == 'all') {
$sphinx_client->SetSortMode(SPH_SORT_RELEVANCE, 'category');
} else {
$sphinx_client->setFilter('category', array($this->_filter_category), FALSE);
}
$sphinx_client->SetLimits(0, $this->_limit);
$results = $sphinx_client->Query('"^'.$query.'$"', 'FULL');
for example i have those names in index :
1. Alex
2. Alen
3. George
4. A
5. G
::: When i try to search for simple 1 char string "A" i get Alen / Alex / A and so on.
How can i search based on string length so i can display them in right order like :
A / Alen / Alex ...
I also get "WARNING: index 'FULL': no morphology, index_exact_words=1 has no effect, ignoring"
Best Regards
use an ordinal field ( str2ordinal ) , do your normal search , but modify sort mode : switch to extended mode and use a combination like $sphinx_client->SetSortMode(SPH_SORT_EXTENDED, '#weight desc , myordinal asc');
The following code is a graphic rendering of the Earth globe spinning eastward. I have two push buttons, Spin and Stop. Both share the same callback function, hAnimaCallback. In particular, this latter does not work. I pretend to use the strings (names) of the push buttons to create a switch that stops the movement. However, I can not get to change the string name inside the while loop and I do not understand why my method is wrong.
function example
fh = figure('Menu','none','Toolbar','none','Units','characters');
T = 0:pi/100:2*pi;
Y = zeros(numel(T),3);
Y(:,1) = 7000*cos(T);
Y(:,2) = 7000*sin(T);
hPanAni = uipanel('parent',fh,'Units','characters','Position',...
[22.6 10.4 53 23],'title','Controls','FontSize',11,...
'FontAngle','italic','FontWeight','bold');
hIniAni = uicontrol(hPanAni,'Style','pushbutton','Units','normalized',...
'Position',[0.14 0.64 0.5 0.12],'String','Spin',...
'FontSize',10,'Callback',#hAnimaCallback);
hFinAni = uicontrol(hPanAni,'Style','pushbutton','Units','normalized',...
'Position',[0.14 0.26 0.5 0.12],'String','Stop',...
'FontSize',10,'Callback',#hAnimaCallback);
hPantSim = uipanel('Parent',fh,'Units','characters',...
'Position',[107.87 8 157.447 42],'BorderType','none','title',...
'Screen','FontSize',11,'FontAngle','italic',...
'FontWeight','bold');
hPantSimInt = uipanel('Parent',hPantSim,'Units','normalized','Position',...
[0 0 1 1],'BorderType','line','BackgroundColor','black');
ah4 = axes('Parent',hPantSimInt,'Units','normalized','Position',...
[0 0 1 1],'Color','none','Visible','off','DataAspectRatio',...
[1 1 1],'NextPlot','add');
rotate3d(ah4);
hgrot = hgtransform('Parent',ah4);
Resf = 6378;
maptext = imread('tierra.jpg');
[X, map] = rgb2ind(maptext,128);
[x,y,z] = sphere(50);
x = Resf*x;
y = Resf*y;
z = Resf*z;
props.FaceColor= 'texture';
props.EdgeColor = 'none';
props.Parent = hgrot;
props.Cdata = flipud(X); % it is necesary to do this for getting the
% appropiate image on the sphere
hsurf = surface(x,y,z,props);
colormap(map);
axis equal;
view([71 14]);
set(gcf,'Renderer','opengl')
drawnow;
line('parent',ah4,'XData',Y(:,1),'YData',Y(:,2),'ZData',...
Y(:,3),'Color','red','LineWidth',2);
line('parent',ah4,'XData',Y(end,1),'YData',Y(end,2),...
'ZData',Y(end,3),'Marker','o','MarkerSize',6,'MarkerFaceColor','b');
axis square equal vis3d;
view(3);
handles.XLim = get(ah4,'XLim');
handles.YLim = get(ah4,'YLim');
handles.ZLim = get(ah4,'ZLim');
xmin = handles.XLim(1);
ymin = handles.YLim(1);
zmin = handles.ZLim(1);
xmax = handles.XLim(2);
ymax = handles.YLim(2);
zmax = handles.ZLim(2);
set(ah4, 'XLim', [xmin xmax],'YLim', [ymin ymax],'Zlim',[zmin zmax]);
az = 0;
function hAnimaCallback(hObject,evt)
while (ishandle(fh))
state = get(hObject,'String'), % state should change between the states of
% Spin and Stop but this does not occur
if (strcmp(state,'Stop'))
break;
else
az = az + 0.01745329252;
set(hgrot,'Matrix',makehgtform('zrotate',az));
drawnow;
end
end
end
end
It seems like you are running into some kind of race condition because of the repeated drawnow calls in the while loop. The state changes to Stop, when you press the Stop button, but it is to quick to notice. Basically, the while loop is running as fast as MATLAB can run. Instead of drawnow using a pause(0.1) command seems to work (with a little bit code logic changes):
az = 0;
spin = false;
function hAnimaCallback(hObject,~)
state = get(hObject,'String')
if strcmp(state, 'Spin')
spin = true;
else
spin = false;
end
while (spin)
az = az + 0.01745329252;
set(hgrot,'Matrix',makehgtform('zrotate',az));
pause(0.1);
end
end
Here is a question for the Excel / math-wizards.
I'm having trouble doing a calculation which is based on a formula with a circular reference. The calculation has been done in an Excel worksheet.
I've deducted the following equations from an Excel file:
a = 240000
b = 1400 + c + 850 + 2995
c = CEIL( ( a + b ) * 0.015, 100 )
After the iterations the total of A+B is supposed to be 249045 (where b = 9045).
In the Excel file this gives a circular reference, which is set to be allowed to iterate 4 times.
My problem: Recreate the calculation in AS2, going through 4 iterations.
I am not good enough at math to break this problem down.
Can anyone out there help me?
Edit: I've changed the formatting of the number in variable a. Sorry, I'm from DK and we use period as a thousand separator. I've removed it to avoid confusion :-)
2nd edit: The third equation, C uses Excels CEIL() function to round the number to nearest hundredth.
I don't know action script, but I think you want:
a = 240000
c = 0
for (i = 0; i < 4; i++){
b = 1400 + c + 850 + 2995
c = (a + b) * 0.015
}
But you need to determine what to use for the initial value of c. I assume that Excel uses 0, since I get the same value when running the above as I get in Excel with iterations = 4, c = 3734.69...
Where do you get the "A + B is supposed to be 249045" value? In Excel and in the above AS, b only reaches 8979 with those values.
function calcRegistrationTax( amount, iterations ) {
function roundToWhole( n, to ) {
if( n > 0 )
return Math.ceil( n/ to ) * to;
else if( n < 0)
return Math.floor( n/ to ) * to;
else
return to;
}
var a = amount;
var b = 0;
var c = 0
for (var i = 0; i < iterations; i++){
b = basicCost + ( c ) + financeDeclaration + handlingFee;
c = ( a + b ) * basicFeeRatio;
c = roundToWhole( c, 100 );
}
return b;
}
totalAmount = 240000 + calcRegistrationTax( 240000, 4 ); // This gives 249045
This did it, thanks to Benjamin for the help.