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I am coming from ode45 in MATLAB trying to learn ode in scilab. I ran into an exception I am not sure how to address.
function der = f(t,x)
wn3 = 2800 * %pi/30; //rad/s
m = 868.1/32.174; //slugs
k = m*wn3^2; //lbf/ft
w = 4100 * %pi/30; //rad/s
re_me = 4.09/32.174/12; //slug-ft
F0 = w^2*re_me; //lbf
der(1) = x(2);
der(2) = -k*x(1) + F0*sin(w*t);
endfunction
x0 = [0; 0];
t = 0:0.1:5;
t0 = t(1);
x = ode(x0,t0,t,f);
plot(t,x(1,:));
I get this error message that I don't understand:
lsoda-- at t (=r1), mxstep (=i1) steps
needed before reaching tout
where i1 is : 500
where r1 is : 0.1027287737654D+01
Excessive work done on this call (perhaps wrong jacobian type).
at line 35 of executed file C:\Users\ndomenico\Documents\Scilab\high_frequency_vibrator_amplitude_3d.sce
ode: lsoda exit with state -1.
Thank you!
Your ode is particularly stiff (k = 2319733). To me, it has no sense to give such a large final time. The time step you took (0.1) is also very large w.r.t to the driving frequency. If you replace the line
t = 0:0.1:5
by
t = linspace(0,0.1,1001)
i.e. request approximations of your solution for t in [0,0.1] and 1000 time steps you will have the following output:
I am reading a line from a text file. It contains the date in YYYY-MM-DD format. I am trying to convert it to datetime object so as to find the difference between two dates.
l = datetime.strptime(last_execution_date,"%Y-%m-%d").date()
Its throwing an error:ValueError: unconverted data remains:
But when I am using below its working perfectly fine
l = datetime.strptime('2019-01-25',"%Y-%m-%d").date()
My complete code looks something like this:
def incoming_mails_duration():
f = open('last_script_execution_time.txt', 'r')
last_execution_date = f.readline()
print(last_execution_date)
print(type(last_execution_date))
l = datetime.strptime(last_execution_date,"%Y-%m-%d").date()
print(l)
print(type(l))
present_date = date.today()
delta_days = abs((present_date - l).days)
f.close()
Why I am getting the above error when I am passing the string as variable read from a file ?
It is because f.readline() returns string with \n in the end. You either have to strip the newline character or include it inside strptime format argument.
Solution 1:
last_execution_date = f.readline().strip()
Solution 2:
l = datetime.strptime(last_execution_date,"%Y-%m-%d\n").date() # Note \n
Note
Also it is good practice to open files with with statement. This is a safe way to handle files. File will be safely closed even if exception occurred inside with block.
with open(filepath) as f:
for line in f:
# Work with line here
pass
I am trying to compare the input string with the strings present in the doc. I am using strcmp for the purpose. These are non-English strings. When the input string is English language, the output is correct. But for any Kannada (non-English language) word the output is the same. I am trying to write a program to check if the word is present in the database. Please guide me in what could be the problem.
The calling function is as below:
str_kan = handles.InputBox.String;
res = strcmp('str_kan','s1.text')
if res == 1 then handles.InputBox.String = string( ' present')
abort
else
handles.InputBox.String = string( 'not present')
abort
end
The whole program is as below:
global s1
f=figure('figure_position',[400,50],'figure_size',[640,480],'auto_resize','on','background',[33],'figure_name','Graphic window number %d','dockable','off','infobar_visible','off','toolbar_visible','off','menubar_visible','off','default_axes','on','visible','off');
handles.dummy = 0;
handles.InputBox=uicontrol(f,'unit','normalized','BackgroundColor',[-1,-1,-1],'Enable','on','FontAngle','normal','FontName','Tunga','FontSize',[12],'FontUnits','points','FontWeight','normal','ForegroundColor',[-1,-1,-1],'HorizontalAlignment','left','ListboxTop',[],'Max',[1],'Min',[0],'Position',[0.0929487,0.6568182,0.4647436,0.1795455],'Relief','default','SliderStep',[0.01,0.1],'String','Enter a Kannada Word','Style','edit','Value',[0],'VerticalAlignment','middle','Visible','on','Tag','InputBox','Callback','')
handles.CheckDB=uicontrol(f,'unit','normalized','BackgroundColor',[-1,-1,-1],'Enable','on','FontAngle','normal','FontName','Tahoma','FontSize',[12],'FontUnits','points','FontWeight','normal','ForegroundColor',[-1,-1,-1],'HorizontalAlignment','center','ListboxTop',[],'Max',[1],'Min',[0],'Position',[0.1025641,0.4636364,0.4567308,0.1204545],'Relief','default','SliderStep',[0.01,0.1],'String','Check','Style','pushbutton','Value',[0],'VerticalAlignment','middle','Visible','on','Tag','CheckDB','Callback','CheckDB_callback(handles)')
f.visible = "on";
function CheckDB_callback(handles)
str_kan = handles.InputBox.String;
res = strcmp('str_kan','s1.text')
if res == 1 then handles.InputBox.String = string( ' present')
abort
else
handles.InputBox.String = string( 'not present')
abort
end
endfunction
Here is an example showing that, in Scilab, strcmp() does support UTF-8 extended characters:
--> strcmp(["aα" "aα" "aβ"], ["aα" "aβ" "aα"])
ans =
0. -1. 1.
The problem in the original posted code is the confusion between literal values as "Hello" and variables names as Hello="my text", as already noted by PTRK.
I'm using Python 3.4.2 and PyPDF2 1.24 (also using reportlab 3.1.44 in case that helps) on windows 7.
I recently upgraded from Python 2.7 to 3.4, and am in the process of porting my code. This code is used to create a blank pdf page with links embedded in it (using reportlab) and merge it (using PyPDF2) with an existing pdf page. I had an issue with reportlab in that saving the canvas used StringIO which needed to be changed to BytesIO, but after doing that I ran into this error:
Traceback (most recent call last):
File "C:\cms_software\pdf_replica\builder.py", line 401, in merge_pdf_files
input_page.mergePage(link_page)
File "C:\Python34\lib\site-packages\PyPDF2\pdf.py", line 2013, in mergePage
self.mergePage(page2)
File "C:\Python34\lib\site-packages\PyPDF2\pdf.py", line 2059, in mergePage
page2Content = PageObject._pushPopGS(page2Content, self.pdf)
File "C:\Python34\lib\site-packages\PyPDF2\pdf.py", line 1973, in _pushPopGS
stream = ContentStream(contents, pdf)
File "C:\Python34\lib\site-packages\PyPDF2\pdf.py", line 2446, in __init
stream = BytesIO(b_(stream.getData()))
File "C:\Python34\lib\site-packages\PyPDF2\generic.py", line 826, in getData
decoded._data = filters.decodeStreamData(self)
File "C:\Python34\lib\site-packages\PyPDF2\filters.py", line 326, in decodeStreamData
data = ASCII85Decode.decode(data)
File "C:\Python34\lib\site-packages\PyPDF2\filters.py", line 264, in decode
data = [y for y in data if not (y in ' \n\r\t')]
File "C:\Python34\lib\site-packages\PyPDF2\filters.py", line 264, in
data = [y for y in data if not (y in ' \n\r\t')]
TypeError: 'in <string>' requires string as left operand, not int
Here is the line and the line above where the traceback mentions:
link_page = self.make_pdf_link_page(pdf, size, margin, scale_factor, debug_article_links)
if link_page != None:
input_page.mergePage(link_page)
Here are the relevant parts of that make_pdf_link_page function:
packet = io.BytesIO()
can = canvas.Canvas(packet, pagesize=(size['width'], size['height']))
....# left out code here is just reportlab specifics for size and url stuff
can.linkURL(url, r1, thickness=1, color=colors.green)
can.rect(x1, y1, width, height, stroke=1, fill=0)
# create a new PDF with Reportlab that has the url link embedded
can.save()
packet.seek(0)
try:
new_pdf = PdfFileReader(packet)
except Exception as e:
logger.exception('e')
return None
return new_pdf.getPage(0)
I'm assuming it's a problem with using BytesIO, but I can't create the page with reportlab with StringIO. This is a critical feature that used to work perfectly with Python 2.7, so I'd appreciate any kind of feedback on this. Thanks!
UPDATE:
I've also tried changing from using BytesIO to just writing to a temp file, then merging. Unfortunately I got the same error.
Here is tempfile version:
import tempfile
temp_dir = tempfile.gettempdir()
temp_path = os.path.join(temp_dir, "tmp.pdf")
can = canvas.Canvas(temp_path, pagesize=(size['width'], size['height']))
....
can.showPage()
can.save()
try:
new_pdf = PdfFileReader(temp_path)
except Exception as e:
logger.exception('e')
return None
return new_pdf.getPage(0)
UPDATE:
I found an interesting bit of information on this. It seems if I comment out the can.rect and can.linkURL calls it will merge. So drawing anything on a page, then trying to merge it with my existing pdf is causing the error.
After digging in to PyPDF2 library code, I was able to find my own answer. For python 3 users, old libraries can be tricky. Even if they say they support python 3, they don't necessarily test everything. In this case, the problem was with the class ASCII85Decode in filters.py in PyPDF2. For python 3, this class needs to return bytes. I borrowed the code for this same type of function from pdfminer3k, which is a port for python 3 of pdfminer. If you exchange the ASCII85Decode() class for this code, it will work:
import struct
class ASCII85Decode(object):
def decode(data, decodeParms=None):
if isinstance(data, str):
data = data.encode('ascii')
n = b = 0
out = bytearray()
for c in data:
if ord('!') <= c and c <= ord('u'):
n += 1
b = b*85+(c-33)
if n == 5:
out += struct.pack(b'>L',b)
n = b = 0
elif c == ord('z'):
assert n == 0
out += b'\0\0\0\0'
elif c == ord('~'):
if n:
for _ in range(5-n):
b = b*85+84
out += struct.pack(b'>L',b)[:n-1]
break
return bytes(out)
I am using MySQLdb to talk to mysql database and I am able to retrieve dynamically all the result sets.
My problem is that once I get the result set, there are a couple columns which are declared as timestamps in mysql but when it is retrieved, it turns to None.
I have two columns, both are declared timestamps but one returns correct data while other returns None. Both utime and enddate are declared timestamps but utime does not return correctly while enddate does.
['utime', 'userstr', 'vstr_client', 'enddate']
((None, '000102030ff43260gg0809000000000004', '7.7.0', '1970-01-01 12:00:00.000000'))
def parse_data_and_description(cursor, data):
res = []
cols = [d[0] for d in cursor.description]
print cols
print data
for i in data:
res.append(OrderedDict(zip(cols, i)))
return res
def call_multi_rs(sp, args):
rs_id=0;
conn = connect()
cursor = conn.cursor()
try:
conn.autocommit(True)
cursor.execute ("CALL %s%s" % (sp, args))
while True:
rs_id+=1
data = cursor.fetchone( )
listout = parse_data_and_description(cursor, data)
print listout
if cursor.nextset( )==None:
# This means no more recordsets available
break
Finally after nobody answered or tried finding more information, I went ahead and looked for more solutions and found that the MySQLdb library converts the datatypes from sql to python and there is a bug which does not convert the timestamp.
I still do not know why one of them is converted and the other is not. If somebody can figure that out, please update this.
But here is the modification that needs to be done when connecting to the mysql database.
MySQLdb can't serialize a python datetime object
try:
import MySQLdb.converters
except ImportError:
_connarg('conv')
def connect(host='abc.dev.local', user='abc', passwd='def', db='myabc', port=3306):
try:
orig_conv = MySQLdb.converters.conversions
conv_iter = iter(orig_conv)
convert = dict(zip(conv_iter, [str,] * len(orig_conv.keys())))
print "Connecting host=%s user=%s db=%s port=%d" % (host, user, db, port)
conn = MySQLdb.connect(host, user, passwd, db, port, conv=convert)
except MySQLdb.Error, e:
print "Error connecting %d: %s" % (e.args[0], e.args[1])
return conn
I stumbled upon the same problem: Retrieving data of the DATETIME(1)-type returns None.
Some research brought up MySQLdb-Bug #325. According to that bug tracker, the issue is still open (has been for over 2 years now), but the comments provide a working solution:
In times.py of the MySQLdb package, you need to insert some lines to handle microseconds like this:
def DateTime_or_None(s):
if ' ' in s:
sep = ' '
elif 'T' in s:
sep = 'T'
else:
return Date_or_None(s)
try:
d, t = s.split(sep, 1)
if '.' in t:
t, ms = t.split('.',1)
ms = ms.ljust(6, '0')
else:
ms = 0
return datetime(*[ int(x) for x in d.split('-')+t.split(':')+[ms] ])
except (SystemExit, KeyboardInterrupt):
raise
except:
return Date_or_None(s)
def TimeDelta_or_None(s):
try:
h, m, s = s.split(':')
if '.' in s:
s, ms = s.split('.')
ms = ms.ljust(6, '0')
else:
ms = 0
h, m, s, ms = int(h), int(m), int(s), int(ms)
td = timedelta(hours=abs(h), minutes=m, seconds=s,
microseconds=ms)
if h < 0:
return -td
else:
return td
except ValueError:
# unpacking or int/float conversion failed
return None
def Time_or_None(s):
try:
h, m, s = s.split(':')
if '.' in s:
s, ms = s.split('.')
ms = ms.ljust(6, '0')
else:
ms = 0
h, m, s, ms = int(h), int(m), int(s), int(ms)
return time(hour=h, minute=m, second=s, microsecond=ms)
except ValueError:
return None
What I cannot explain, though, is your original query working on one column and not on the other.. Maybe, the second does not have any microsecond-information in it?