[Tutor] Do loop in Python
Hi there,
I am a new python user.
I have a question regarding do loop.
This is a simple program that I have written:
-
N=10
h=10.0 # [micrometer]
z=-200.0 # [micrometer]
num = 0.05 #m**2/s
dz = 1.0
nuh=[]
tmax=3600
dt=20.
nu=[]height = arange(z*dz,0,dz)
outfile=open('nu.dat','w')
outfile.write('height, nu, nuh')
for z,when in enumerate(height):
for h in range(10):
for N in range(10):
for z in range((N-z)+(N-h)):
nuh.append(0.01 * exp(-0.05*(z+200.0))*dz) #turbulence
diffusivity m**2/s
nu.append(num + nuh[z])
---
What I like to do with this program is do loop like the fortran
version of as follows:
do i = 2, N
z(i) = z(i-1) +h(i-1)
end do
write(0,*) 'z ', z(1:N)
write(0,*) 'when ', 'nu ','Conc '
do i= 1, N
nuh(i)= 0.01d0*exp(-0.005d2*(z(i)+200)) ! turbulence diffusivity m**2/s
nu(i)= num(1) + nuh(i)
end do
--
My problem is I am notable have the curve in the output plot as I have
as a result of FORTRAN program. What happens is just having a
straight line!
the whole problem is in z part, which is supposed to be changed and i
do not see it!
So, would it be possible to take a look at it please. any suggestion
would greatly appreciated.
Thank you,
Sue
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Re: [Tutor] Do loop in Python
regarding to the last email:
what I am trying to do is seeing the variation of 'nu' over (changes of) 'z'.
My concern is how to arrange this!
Basically, I am not able to define the variation of nu by z ( 1 to
200). I am looking for a statement to show the changes of 'nu' for
each step of z (as height).
On the other hand, for each step, 'h' is supposed to be subtracted
from 'z' (like: 200-10, 190-10...) as well, at least 10 times (which
was trying to be defined as N)!
I hope this is somehow clear
Thanks in advance,
Sue
- Show quoted text -
On Fri, Nov 25, 2011 at 10:16 AM, stm atoc wrote:
> Hi there,
>
> I am a new python user.
> I have a question regarding do loop.
>
> This is a simple program that I have written:
>
> -
> N=10
> h=10.0 # [micrometer]
> z=-200.0 # [micrometer]
> num = 0.05 #m**2/s
> dz = 1.0
> nuh=[]
> tmax=3600
> dt=20.
> nu=[]height = arange(z*dz,0,dz)
>
> outfile=open('nu.dat','w')
> outfile.write('height, nu, nuh')
>
> for z,when in enumerate(height):
> for h in range(10):
> for N in range(10):
> for z in range((N-z)+(N-h)):
>
> nuh.append(0.01 * exp(-0.05*(z+200.0))*dz) #turbulence
> diffusivity m**2/s
> nu.append(num + nuh[z])
>
> ---
> What I like to do with this program is do loop like the fortran
> version of as follows:
>
> do i = 2, N
> z(i) = z(i-1) +h(i-1)
>
> end do
>
> write(0,*) 'z ', z(1:N)
> write(0,*) 'when ', 'nu ','Conc '
>
>
> do i= 1, N
>
> nuh(i)= 0.01d0*exp(-0.005d2*(z(i)+200)) ! turbulence diffusivity m**2/s
> nu(i)= num(1) + nuh(i)
>
>
> end do
>
> --
> My problem is I am notable have the curve in the output plot as I have
> as a result of FORTRAN program. What happens is just having a
> straight line!
> the whole problem is in z part, which is supposed to be changed and i
> do not see it!
>
> So, would it be possible to take a look at it please. any suggestion
> would greatly appreciated.
>
> Thank you,
> Sue
>
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Re: [Tutor] Do loop in Python
Thank you so much for your reply. It was very helpful information and
I used it in order to improve the program
Here is the new version of the program:
zvalues = [-200] # starting value
hvalues = [10] # starting value
increments = [1, 1, 1, 1, 1, 1, 1, 1]
for N in increments:
h = hvalues[-1] - N
hvalues.append(h)
z = zvalues[-1] + h
zvalues.append(z)
height = arange((z)*dz,0,dz)
for z,when in enumerate(height):
nuh.append(0.001 * exp(-0.005*(z+200.0))*dz) #turbulence
diffusivity m**2/s
nu.append(num + nuh[z])
The story is like this:
I should define layers and thickness and see how the diffusion profile
changes over the z.
height (or depth) of the total thickness or 'z'.
I basically, define 'z' in 10 layers and each layer is called ' N' .
Difference between each layer is 'h', which is equal 10 micrometer.
Now, what I like to do is the modification of nu based on each zvalue
In fact, for each 'zvalue' o'z' step, I need to calculate a different
value for 'nu' based on the available equation in the program.
BUT, I am not sure, exactly, how to add the new do loop of z inside
another loop of nu.
I have done this way as well (the other way around):
height = arange((z)*dz,0,dz)
for z,when in enumerate(height):
for N in increments:
h = hvalues[-1] - N
hvalues.append(h)
z = zvalues[-1] + h
zvalues.append(z)
nuh.append(0.001 * exp(-0.005*(z+200.0))*dz) #turbulence
diffusivity m**2/s
nu.append(num + nuh[z])
but still no sign of 'nu changes' over 'z'!
So, would it be possible to check that again?
Thanks, Sue
On Fri, Nov 25, 2011 at 12:36 PM, Steven D'Aprano wrote:
> stm atoc wrote:
>>
>> Hi there,
>>
>> I am a new python user.
>> I have a question regarding do loop.
>>
>> This is a simple program that I have written:
>>
>> -
>> N=10
>> h=10.0 # [micrometer]
>> z=-200.0 # [micrometer]
>
> You define N, h and z here, but later on you use them as loop variables. So
> these three values never get used: they are thrown away, and replaced by the
> values of the loops:
>
> h -> 0, 1, 2, ... 9
> N -> 0, 1, 2, ... 9
>
> z is especially troublesome, because it gets used for TWO loop variables,
> one inside the other. The inner z loop depends on the outer z loop, which
> makes it tricky to predict what values z will take.
>
>
>> num = 0.05 #m**2/s
>> dz = 1.0
>> nuh=[]
>> tmax=3600
>> dt=20.
>> nu=[]height = arange(z*dz,0,dz)
>
> What is arange?
>
> In physics, "height" is a scalar. But later on, you seen to use height as if
> it were a collection of values.
>
>
>> outfile=open('nu.dat','w')
>> outfile.write('height, nu, nuh')
>>
>> for z,when in enumerate(height):
>> for h in range(10):
>> for N in range(10):
>> for z in range((N-z)+(N-h)):
>>
>> nuh.append(0.01 * exp(-0.05*(z+200.0))*dz) #turbulence
>> diffusivity m**2/s
>> nu.append(num + nuh[z])
>>
>> ---
>> What I like to do with this program is do loop like the fortran
>> version of as follows:
>>
>> do i = 2, N
>> z(i) = z(i-1) +h(i-1)
>>
>> end do
>
>
> How is z initialised? What is h?
>
>
> I *think* you are trying to add a small increment to each value, based on
> the previous value. Am I close?
>
>
> Does this example help?
>
>
> zvalues = [1] # starting value
> increments = [0.01, 0.01, 0.02, 0.01, 0.01, 0.02, 0.01, 0.01]
> for h in increments:
> z = zvalues[-1] + h
> zvalues.append(z)
>
> print(zvalues)
>
>
> (Note: beware of floating point rounding.)
>
>
>
>
> --
> Steven
>
> ___
> Tutor maillist - Tutor@python.org
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>
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Re: [Tutor] Do loop in Python
Thank you so much. This script and all information was totally helpful and actually helped me for the next step of my work as well. Have a great time. Sue On Fri, Nov 25, 2011 at 10:44 PM, Andreas Perstinger wrote: > On 2011-11-25 14:46, stm atoc wrote: >> >> Here is the new version of the program: >> >> zvalues = [-200] # starting value >> hvalues = [10] # starting value >> increments = [1, 1, 1, 1, 1, 1, 1, 1] >> for N in increments: >> h = hvalues[-1] - N >> hvalues.append(h) >> z = zvalues[-1] + h >> zvalues.append(z) >> height = arange((z)*dz,0,dz) > > > There is no "arange" in python. Could it be that you use numpy and import it > with "from numpy import *"? > >> for z,when in enumerate(height): > > > I'm pretty sure this line doesn't do what you expect it to do. You have a > sequence (a numpy array) named "height" and after calling "enumerate" you > get a list of tuples in the form of [(0, height[0]), (1, height[1]), ...]. > Now the for-loop iterates over this list and assigns "z" to the first value > of the tuple (the index-values) and "when" to the second (the values from > "height"). You later never use "when" but just use "z". If you really want > that, the "enumerate" is completly unnecessary and you could just use "for z > in range(len(height))". But I'm not sure if numpy arrays work with "len()". > > >> nuh.append(0.001 * exp(-0.005*(z+200.0))*dz) #turbulence >> diffusivity m**2/s >> nu.append(num + nuh[z]) >> >> The story is like this: >> I should define layers and thickness and see how the diffusion profile >> changes over the z. >> height (or depth) of the total thickness or 'z'. >> I basically, define 'z' in 10 layers and each layer is called ' N' . >> Difference between each layer is 'h', which is equal 10 micrometer. >> Now, what I like to do is the modification of nu based on each zvalue >> In fact, for each 'zvalue' o'z' step, I need to calculate a different >> value for 'nu' based on the available equation in the program. >> >> BUT, I am not sure, exactly, how to add the new do loop of z inside >> another loop of nu. > > > For me your explanations are still too confusing. Could it be that you are > thinking way too complicated? > > My guess is you want to have a range of material thicknesses (from 1 to 200 > micrometers in 10 micrometer-steps) and then you want from each thickness 10 > different layers, right? > > import math # you should always tell us which modules you import > num = 0.05 # some constant > nu = [] # list of resulting values > h = 10.0 # height of one layer > thickness = range(0, 210, 10) # a list from 0 to 200 with step 10 (0, 10, > 20, ..., 190, 200) > layers = range(1,11) # a list from 1 to 10 > for t in thickness: > for l in layers: > z = t + h * l # I'm not sure if you want to add or subtract the layer > thickness > nu = num + (0.01 * math.exp(-0.05 * (z + 200.0))) > > This will result in a big one-dimensional list where you calculate for each > thickness the nu-value for 10 layers. Am I close? > I'm still not sure about the steps and the height of the layers. I also > wonder if it wouldn't be better to use a two-dimensional list. > > >> I have done this way as well (the other way around): >> >> height = arange((z)*dz,0,dz) >> for z,when in enumerate(height): >> for N in increments: >> h = hvalues[-1] - N >> hvalues.append(h) >> z = zvalues[-1] + h >> zvalues.append(z) >> nuh.append(0.001 * exp(-0.005*(z+200.0))*dz) #turbulence >> diffusivity m**2/s >> nu.append(num + nuh[z]) >> >> but still no sign of 'nu changes' over 'z'! > > > As Charles has already mentioned, the values for "nu" are very similar (they > start beginning to differ just at the seventh digit after the comma). How do > you further process this values? If you plot them what's your scale? > > Bye, Andreas > > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] plotting in python
Hi there,
I have a question regarding plotting with Python.
I have the following python script:
# coding: utf-8
from pylab import *
import numpy
filename='ourtest_out.list'
fh=open(filename)
line=fh.readline()
fh.close
z=array([ float(val) for val in line.split()[1:] ])
a = numpy.loadtxt(filename,skiprows=3)
N=100
t = a[:,0]
nu = a[0:,1:N+1]
#Conc = a[1:,N+1:]
Conc = a[1:,N+1:]
levels=arange(-10,1)
levels=levels[-3]-levels
t=t/360.
figure()
plot(Conc[0],z)
xlabel('C')
ylabel('z')
#show()
savefig('Conc.png')
close()
#nu
figure()
lw = 2.0 #linewidth
dpi = 96
levels=arange(-10,1)
levels=levels[-3]-levels
plot(nu[0],z)
xlabel('nu')
ylabel('z')
savefig('nu.png')
close()
However, once I run the program (run.py)
I have error like this:
---
ValueErrorTraceback (most recent call last)
/Users/…./run.py in ()
24
25 figure()
---> 26 plot(Conc[0],z)
27
28 xlabel('C')
/Library/Frameworks/EPD64.framework/Versions/7.1/lib/python2.7/site-packages/matplotlib/pyplot.py
in plot(*args, **kwargs)
2284 ax.hold(hold)
2285 try:
-> 2286 ret = ax.plot(*args, **kwargs)
2287 draw_if_interactive()
2288 finally:
/Library/Frameworks/EPD64.framework/Versions/7.1/lib/python2.7/site-packages/matplotlib/axes.py
in plot(self, *args, **kwargs)
3781 lines = []
3782
-> 3783 for line in self._get_lines(*args, **kwargs):
3784 self.add_line(line)
3785 lines.append(line)
/Library/Frameworks/EPD64.framework/Versions/7.1/lib/python2.7/site-packages/matplotlib/axes.py
in _grab_next_args(self, *args, **kwargs)
315 return
316 if len(remaining) <= 3:
--> 317 for seg in self._plot_args(remaining, kwargs):
318 yield seg
319 return
/Library/Frameworks/EPD64.framework/Versions/7.1/lib/python2.7/site-packages/matplotlib/axes.py
in _plot_args(self, tup, kwargs)
292 x = np.arange(y.shape[0], dtype=float)
293
--> 294 x, y = self._xy_from_xy(x, y)
295
296 if self.command == 'plot':
/Library/Frameworks/EPD64.framework/Versions/7.1/lib/python2.7/site-packages/matplotlib/axes.py
in _xy_from_xy(self, x, y)
232 y = np.atleast_1d(y)
233 if x.shape[0] != y.shape[0]:
--> 234 raise ValueError("x and y must have same first dimension")
235 if x.ndim > 2 or y.ndim > 2:
236 raise ValueError("x and y can be no greater than 2-D")
ValueError: x and y must have same first dimension
---So, What would you suggest?
Thanks in advance,
Sue
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Re: [Tutor] Do loop in Python
Yes. Actually, I have changed it to this kine od script: # == model loop == #Optione1 if True: z=zeros( (numlayers,) ) thickness= (thickness*1.0) for l in layers: z = arange ((-thickness - h * l),0,dz) ##z= t -h * l nu = num+ (0.001*exp(-0.005*(z+200.))*dz) #Option2 if False: thickness = range(-200 , 0, 10) # a list from -200 to 0 with step 10 (0, 10, 20, ..., 190, 200) layers = range(1,11) # a list from 1 to 10 for t in thickness: for l in layers: z = arange(( t + h * l ), 0, dz ) #zvalues = arange(-200.,0,dz) nu = num+ (0.001*exp(-0.005*(z+200.))) plot(nu,z) Then it seems it works. it should have a trend to reducing values... - Show quoted text - On Tue, Nov 29, 2011 at 2:00 PM, Steven D'Aprano wrote: > stm atoc wrote: >> >> Thank you so much for your reply. It was very helpful information and >> I used it in order to improve the program >> >> Here is the new version of the program: >> >> zvalues = [-200] # starting value >> hvalues = [10] # starting value >> increments = [1, 1, 1, 1, 1, 1, 1, 1] >> for N in increments: >> h = hvalues[-1] - N >> hvalues.append(h) >> z = zvalues[-1] + h >> zvalues.append(z) >> height = arange((z)*dz,0,dz) >> for z,when in enumerate(height): >> nuh.append(0.001 * exp(-0.005*(z+200.0))*dz) #turbulence >> diffusivity m**2/s >> nu.append(num + nuh[z]) > > > > I'm afraid I still don't know what the arange function is. Is that a > function you have written yourself? However, I can see that it doesn't > actually get used! > > You create an arange object, and call it "height". > > height = arange((z)*dz,0,dz) > > You should insert a print statement after this line to see what value height > is given, and check that it is what you expect it to be. > > Presumably height is some sort of list or sequence of values, because you > next use it in a for-loop: > > for z,when in enumerate(height): > ... > > So now we know that z takes on the values 0, 1, 2, 3, ... and when takes on > the values from height, whatever they are. But in the rest of your code, you > don't use when at all: > > nuh.append(0.001 * exp(-0.005*(z+200.0))*dz) > > nu.append(num + nuh[z]) > > No when, hence the values from height aren't actually used. Strange. > > Also, what are dz and num? You use them both, but I can't see where they are > defined or what value they have. Likewise nuh and nu, although I can guess > they are probably lists because you append to them. > > Because I don't know what values to use, and I don't know what arange is, I > can't run your code to see what it does. So I'm reduced to guessing. > > If I take a wild stab in the dark that dz is a small number, say, 0.01, I > can see what values nuh gets: > > > py> from math import exp > py> dz = 0.01 > py> nuh = [] > py> for z in range(10): > ... nuh.append(0.001 * exp(-0.005*(z+200.0))*dz) > ... > py> from pprint import pprint > py> pprint(nuh) > [3.6787944117144236e-06, > 3.6604463480401533e-06, > 3.6421897957152333e-06, > 3.624024298324903e-06, > 3.6059494017307832e-06, > 3.587964654059516e-06, > 3.5700696056914737e-06, > 3.5522638092495153e-06, > 3.5345468195878014e-06, > 3.5169181937806692e-06] > > Is that the sort of behaviour you expect for nuh? > > Since the nuh values are changing, num+nuh[z] should also be changing, which > implies nu should be changing. > > Unless num is so large that rounding error wipes out the nuh values. > > > > > -- > Steven > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] plotting in python
The output of the print len(Conc[0]), len(z) is 100 3600. Now I changed Conc[0] to Conc[1], and the output is: 100 100 But still I need to see from Concentration from 0. On Thu, Dec 1, 2011 at 5:26 AM, Asokan Pichai wrote: > On Thu, Dec 1, 2011 at 2:38 AM, stm atoc wrote: >> Hi there, >> >> I have a question regarding plotting with Python. >> >> I have the following python script: > > [SNIPPED] >> plot(Conc[0],z) > > [SNIPPED] >> ---So, What would you suggest? > > What is the output of > print len(Conc[0]), len(z) > > You may insert that line above the plot and see > > Asokan Pichai ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] plotting in python
For previous script that I have written, I had trouble having one plot
for all data at the same time and I could see two line for Conc[0] and
Conc[1] separately. Now, even I modified Conc = a[1:, N+1:] to Conc =
a[0:, N+1:], still one plot is created...which is pretty good and no
error!
Thank you so much,
Sue
On Thu, Dec 1, 2011 at 12:39 PM, Andreas Perstinger
wrote:
> [Still top-posting :-( ]
>
>
> On 2011-12-01 11:13, stm atoc wrote:
>>
>> Well, I did also change the line in the python script to this:
>>
>> plot(Conc[0],z,'r-',label='initial')
>> plot(Conc[1],z,'b-',label='after 20s')
>>
>> to see both Conc[0] and [1].
>
>
> And did it work?
>
>
>> I will send the output data attaches to this email ("ourtest_out.list").
>>
>> I wonder if this way is fine.
>
>
> I'm not sure about the policy regarding attachements on this list but I
> think it would have been better to provide a link than attach it.
>
> Anyways, I've reduced your original script, did a test run and it works as
> expected (at least it shows a plot):
>
> import numpy
> import matplotlib.pyplot as pyplot
>
> with open("ourtest_out.list", "r") as f:
> z = numpy.array([float(v) for v in f.readline().split()[1:]])
>
> a = numpy.loadtxt("ourtest_out.list", skiprows=3)
> N = 100
> Conc = a[1:, N+1:]
>
> print len(Conc[0]) == len(z)
>
> pyplot.figure()
> pyplot.plot(Conc[0], z)
> pyplot.show()
>
> Do you still get an error?
>
> Bye, Andreas
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[Tutor] New plot over the old graph
Hi there,
I would like to make a new plot with new data over the old one (with
old/first data) in the same condition (shape, dimensions) for
comparison and analysis data.
With your help, I have a good script from the previous discussion:
**
from pylab import *
import numpy
import matplotlib.pyplot as pyplot
import matplotlib.mlab as mlab
with open("ourtest_out.list", "r") as f:
z = numpy.array([float(v) for v in f.readline().split()[1:]])
a = numpy.loadtxt("ourtest_out.list", skiprows=3)
N = 100
Conc = a[0:, N+1:]
print len(Conc[0]) == len(z)
figure()
pyplot.plot(Conc[0],z,'r-',label='initial')
pyplot.plot(Conc[1],z,'b-',label='after 20s')
show()
*
I have tried to make subplot for this case as follows:
pyplot.subplot(111)
pyplot.plot(Conc[0],z,'r-',label='initial')
pyplot.plot(Conc[1],z,'b-',label='after 20s')
However, I am not sure how to add new data over this to make a graph
including both new and old data simultaneously.
I do appreciate for any advice.
Thank you,
Sue
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Re: [Tutor] New plot over the old graph
Thanks for all information/websites and advice. Yes the graph is
exactly like the one you mentioned. Also, I would like to have them in
one not two, but I think since the dimension of the x and y are not
same, I have no choice.
What I like to do now is comparing 2 (later 3 or more) different sets
of data, e.g. comparison among Conc[1] with sets
I have changed the script like this:
with open("ourtest_out.list", "r") as f:
z = numpy.array([float(v) for v in f.readline().split()[1:]])
a1 = numpy.loadtxt("ourtest_out1.list", skiprows=3)
a2 = numpy.loadtxt("ourtest_out2.list", skiprows=3)
a3 = numpy.loadtxt("ourtest_out3.list", skiprows=3)
N = 100
Conc1 = a1[0:, N+1:] #base case
Conc2 = a2[0:, N+1:] # Ydw=0.1
Conc3 = a3[0:, N+1:] # nuh=0.01
lw = 2.0 #linewidth
dpi = 96
figure(figsize=(10,6),dpi=dpi)
pyplot.subplot(111)
pyplot.plot(Conc1[1], z)
pyplot.plot(Conc2[1], z)
pyplot.plot(Conc3[1], z)
pyplot.xlim(0,1)
plt.xlabel('Conc')
plt.ylabel('z')
pyplot.grid(True)
show()
savefig('Conc.png')
close()
This can give me the comparison in one graph, I suppose.
Now, first I like to know if this is a fine/logical script. otherwise
I would like to know about probably a better way to write it with less
lines!
and second, when I do plot, each grid between x or y axis, has a
thickness of 0.2. what I like do is to change it to 0.1 grid . So, I
couldn't find it through matplotlib website (at least with my
searching. Would it be possible helping me about? I am new at python
and a beginner and I do have learn while I work with it...
Thanks in advance,
Sue
On Thu, Dec 1, 2011 at 6:25 PM, Andreas Perstinger
wrote:
> On 2011-12-01 14:30, stm atoc wrote:
>>
>> With your help, I have a good script from the previous discussion:
>>
>> **
>> from pylab import *
>
>
> Have you used MATLAB before and are used to its syntax? In general "star
> imports" (from xxx import *) are a bad practice and IMHO should be avoided.
>
>
>> import numpy
>> import matplotlib.pyplot as pyplot
>> import matplotlib.mlab as mlab
>
>
> These imports are unnecessary if you use the first line because "pylab"
> imports everything from "numpy" and "matplotlib" into a single namespace. So
> either use just the first line (not recommended) or the following line
> (recommended).
>
> See also
> http://matplotlib.sourceforge.net/faq/usage_faq.html#matplotlib-pylab-and-pyplot-how-are-they-related
> and
> http://matplotlib.sourceforge.net/faq/usage_faq.html#coding-styles
>
> BTW: Why do you import "mlab" when you don't use it?
>
>
>> with open("ourtest_out.list", "r") as f:
>> z = numpy.array([float(v) for v in f.readline().split()[1:]])
>>
>> a = numpy.loadtxt("ourtest_out.list", skiprows=3)
>> N = 100
>> Conc = a[0:, N+1:]
>> print len(Conc[0]) == len(z)
>
>
> This line was just for testing. You can delete it without any consequences.
>
>
>
>> figure()
>>
>> pyplot.plot(Conc[0],z,'r-',label='initial')
>> pyplot.plot(Conc[1],z,'b-',label='after 20s')
>>
>> show()
>
>
> Isn't that what you want? You are plotting all your data in one graph. There
> is a straight red line on the left side and a falling blue line from left to
> right.
>
>
>> *
>>
>> I have tried to make subplot for this case as follows:
>>
>> pyplot.subplot(111)
>> pyplot.plot(Conc[0],z,'r-',label='initial')
>> pyplot.plot(Conc[1],z,'b-',label='after 20s')
>
>
> Here you are creating a subplot with 1 plot each row and 1 plot each column,
> in other words you do the same as above (creating just 1 plot). If you want
> to have for example 4 plots in the same window with 2 each row and 2 each
> column you have to use
>
> pyplot.subplot(221)
>
> After plotting all the data in this first "axes" you have to switch to the
> next one:
>
> pyplot.subplot(222)
>
> Have you already read the matplotlib-tutorial:
> http://matplotlib.sourceforge.net/users/pyplot_tutorial.html
>
>
>> However, I am not sure how to add new data over this to make a graph
>> including both new and old data simultaneously.
>
>
> As I've said before: You are already plotting all data in one graph.
> Don't you get two different lines?
>
> Bye, Andreas
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Re: [Tutor] New plot over the old graph
I appreciated for the accurate response.
I used step by step and it is running now.
Thank you very much for your advice and guidance,
Sue
On Thu, Dec 1, 2011 at 10:01 PM, Andreas Perstinger
wrote:
> On 2011-12-01 19:20, stm atoc wrote:
>>
>> Thanks for all information/websites and advice. Yes the graph is
>> exactly like the one you mentioned. Also, I would like to have them in
>> one not two, but I think since the dimension of the x and y are not
>> same, I have no choice.
>>
>> What I like to do now is comparing 2 (later 3 or more) different sets
>> of data, e.g. comparison among Conc[1] with sets
>>
>> I have changed the script like this:
>>
>> with open("ourtest_out.list", "r") as f:
>> z = numpy.array([float(v) for v in f.readline().split()[1:]])
>>
>> a1 = numpy.loadtxt("ourtest_out1.list", skiprows=3)
>> a2 = numpy.loadtxt("ourtest_out2.list", skiprows=3)
>> a3 = numpy.loadtxt("ourtest_out3.list", skiprows=3)
>>
>> N = 100
>>
>> Conc1 = a1[0:, N+1:] #base case
>> Conc2 = a2[0:, N+1:] # Ydw=0.1
>> Conc3 = a3[0:, N+1:] # nuh=0.01
>> lw = 2.0 #linewidth
>
>
> You aren't using "lw" so it doesn't make sense to define it.
>
>> dpi = 96
>> figure(figsize=(10,6),dpi=dpi)
>
>
> I prefer to not clutter up the namespace with "star imports" (from pylabs
> import *) but it's your choice.
>
>>
>> pyplot.subplot(111)
>
>
> If you just use one graph/figure this call is unnecessary.
>
>
>> pyplot.plot(Conc1[1], z)
>> pyplot.plot(Conc2[1], z)
>> pyplot.plot(Conc3[1], z)
>> pyplot.xlim(0,1)
>>
>> plt.xlabel('Conc')
>> plt.ylabel('z')
>
>
> I assume you've got these lines from the tutorial. But there they are using
> the following import:
>
> import matplotlib.pyplot as plt
>
> I've used
>
> import matplotlib.pyplot as pyplot
>
> so you have to decide which name you want to use (You can't mix both).
>
> In general, if you just use
>
> import matplotlib.pyplot
>
> you would have to use always the full name:
>
> matplotlib.pyplot.xlabel('Conc')
>
> But with the "as"-keyword you can choose, which name gets imported into the
> namespace.
>
> If you have problems understanding imports and namespaces look at Alan's
> tutorial:
> http://www.freenetpages.co.uk/hp/alan.gauld/tutfunc.htm (section "Using
> Modules")
> http://www.freenetpages.co.uk/hp/alan.gauld/tutname.htm (about Namespaces)
>
>
>>
>> pyplot.grid(True)
>> show()
>> savefig('Conc.png')
>
>
> You should call "savefig" before "show" because in non-interactive mode
> (calling the script from the commandline) "show" will block all figures
> until they are closed. So after "show" there won't be any figures left and
> "savefig" will write an empty figure to the file.
>
>
>> close()
>>
>> This can give me the comparison in one graph, I suppose.
>> Now, first I like to know if this is a fine/logical script. otherwise
>> I would like to know about probably a better way to write it with less
>> lines!
>
>
> You could write the whole script in a more object-oriented style where you
> create a figure-instance and then set the attributes you want instead of
> calling all the functions. But for the beginning it's ok.
>
>
>> and second, when I do plot, each grid between x or y axis, has a
>> thickness of 0.2. what I like do is to change it to 0.1 grid . So, I
>> couldn't find it through matplotlib website (at least with my
>> searching. Would it be possible helping me about?
>
>
> You set the scale with the "xticks"-function (or the corresponding
> "yticks"):
> http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.xticks
>
> So in your case you could use
>
> pyplot.xticks(numpy.arange(0, 1.1, 0.1))
>
>
> Bye, Andreas
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[Tutor] unsupported operand
Hi there,
I would like to define concentration array based on time and then plot it.
Here is the profile:
from pylab import *
import numpy
import array
import math
tmax=1*3600
t = 1.
outfile=open('ourtest_out.list','w')
N = 100
Conc1 = arange([0, tmax])
outfile.close()
lw = 2.0 #linewidth
dpi = 96
figure(figsize=(12,6),dpi=dpi)
pyplot.plot(Conc1, t,'r-',label='Conc' )
savefig('Conc.png')
show()
and this is the error that I got:
TypeError: unsupported operand type(s) for -: 'list' and 'int'
What would you suggest?
Thank you,
Sue
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Re: [Tutor] unsupported operand
Well, I tried to check and I do not have that problem any more..but i
have the clear script as follows and a couple of question regarding to
this:
# coding: utf-8
from pylab import *
import numpy
import matplotlib.pyplot as pyplot
import matplotlib.mlab as mlab
#tmax=360
with open("ourtest_out.list", "r") as f:
t = numpy.array([float(v) for v in f.readline().split()[1:]])
for t, filename in enumerate("ourtest_out.list"):
a = numpy.loadtxt("ourtest_out.list", skiprows=3)
Conc=[]
#Conc = a[:, 200]
Conc.append(a[:,200])
#Conc = a[0:, tmax+1:]
plot(Conc,t)
show()
My main problem is, i do try to see the plot of Conc according to
time. I have a graph without any data!
Basically, I have a program written in FORTRAN including conc, time,
etc. calculation. The out put data shows that I do have concentration.
However, i am not able to have a plot based on time.
I should mention that I did have run the model (fortran) for
concentration according to the number of layer (N=200) and defined the
concentration like this Conc(0:N). Perhaps the reason that I am not
able to see the concentration with time is because of this definition.
BUT, still if I do plot based on pyplot.pcolor, I have a nice and
seems correct graph.
So, actually, I am not sure what is the problem for showing the
regular/linear plot. I hope I made it clear now..
Would it be possible to give me some hint please?
Thank you in advance,
Sue
On Sun, Dec 18, 2011 at 2:07 AM, Steven D'Aprano wrote:
> stm atoc wrote:
>
>> and this is the error that I got:
>
>
> Would you like us to guess which line causes the error?
>
> Please show the ENTIRE traceback. Do not retype it from memory, paraphrase
> or simplify it, or otherwise change it in any way. Copy and paste it.
>
>
>> TypeError: unsupported operand type(s) for -: 'list' and 'int'
>>
>> What would you suggest?
>
>
> The code sample you showed did not include any subtractions. This hints that
> perhaps you are not showing us all of the code you are actually running. The
> full traceback will answer that one way or the other.
>
> Otherwise, I suggest you look at the line which the traceback prints. It
> probably has something like "result = a - b" (or some other subtraction).
> Look for the two variables: one of them is set to a list.
>
>
> --
> Steven
>
>
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[Tutor] changing coordinate
Hi:
I am trying to define a new coordinate for My plot.
I have a plot x axis is Concentration, Y axis, depth or Z.
Z= -1000 um.
and I would like to see the the trend and plot of concentration up to
-300 um and see how the plot changed according to the depth. So, my
main question is about how to change the coordinate based on 0 to
-300.
This is the relevant description:
# coding: utf-8
from pylab import *
import numpy
import matplotlib.pyplot as pyplot
import matplotlib.mlab as mlab
#t=3600
N = 100
dz = 1.0
h_s=-300
with open("ourtest_out.list", "r") as f:
z = numpy.array([float(v) for v in f.readline().split()[1:]])
z == z + h_s
a = numpy.loadtxt("ourtest_out.list", skiprows=3)
t=a[:,0]
nu = a[0:,1:N+1]
Conc = a[0:, N+1:]
lw = 2.0 #linewidth
dpi = 96
figure(figsize=(12,6),dpi=dpi)
pyplot.plot(Conc[1], z,'r-')
pyplot.xlabel('$Conc, mmol C m^3$')
pyplot.ylabel('$Hsml, micrometer$')
pyplot.grid(True)
legend()
savefig('Conc.png')
show()
lw = 2.0 #linewidth
dpi = 96
figure(figsize=(12,6),dpi=dpi)
semilogx(Conc[1], z,'r-')
pyplot.xlabel('$Conc, mmol C m^3$')
pyplot.ylabel('$Hsml, micrometer$')
pyplot.grid(True)
legend()
savefig('semiConc.png')
show()
lw = 2.0 #linewidth
dpi = 96
figure(figsize=(12,6),dpi=dpi)
semilogx(nu[1], z,'r-')
pyplot.xlabel('$nu, m^2/s^{-1}$')
pyplot.ylabel('$Hsml, micrometer$')
pyplot.grid(True)
legend()
savefig('nu.png')
show()
--
I do appreciate any help and advice.
Thanks,Sue
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[Tutor] TypeError: only length-1 arrays can be converted to Python scalars
Hi,
I have a question regarding the TypeError.
I have this script as follows in Python. I have run a program in Fortran:
# coding: utf-8
from pylab import *
import numpy
import matplotlib.pyplot as pyplot
import matplotlib.mlab as mlab
t=3600
N = 100
dz = 1.0
with open("act_out.list", "r") as f:
z = numpy.array([float(v) for v in f.readline().split()[1:]])
zm = z*1.0e6
a = numpy.loadtxt("act_out.list", skiprows=3)
t=a[:,0]
nu = a[0:,1:N+1]
Conc = a[:, N+1:]
hsml=zeros((103))
cprof=zeros((103))
hsml[0]=-1300.
hsml[-2]=-300.
hsml[-1]=0.
hsml[1:-2]=z*100-300.
cprof[0]=50.
cprof[-2]=500.
cprof[-1]=500.
idx=int(where(t==1800)[0])
cprof[1:-2]=Conc[idx]
lw = 2.0
dpi = 80
figure(figsize=(8,8),dpi=dpi)
pyplot.plot(cprof,hsml,'r-')
pyplot.xlabel('$Conc, mmol C m^3$')
pyplot.ylabel('$Hsml, micrometer$')
pyplot.grid(True)
legend()
savefig('Conc.png')
show()
after runing Python, I hav ethis massage:
TypeError: only length-1 arrays can be converted to Python scalars
Any suggestion? in fact, what I missed and what I should add to have
a right result!
Thanks in advance,
Sue
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