I have a master array of length n of id numbers that apply to other analogous arrays with corresponding data for elements in my simulation that belong to those id numbers (e.g. data[id]). Were I to generate a list of id numbers of length m separately and need the information in the data array for those ids, what is the best method of get...
So if I have a matrix (list of lists) where each column represents a unique word, each row represents a distinct document, and every entry is a 1 or 0, indicating whether or not the word for a given column exists in the document for a given row. What I'd like to know is how to determine all the possible combinations of words and documen...
Suppose I have a numpy array x = [5, 2, 3, 1, 4, 5], y = ['f', 'o', 'o', 'b', 'a', 'r']. I want to select the elements in y corresponding to elements in x that are greater than 1 and less than 5. I tried x = array([5, 2, 3, 1, 4, 5]) y = array(['f','o','o','b','a','r']) output = y[x > 1 & x < 5] # desired output is ['o','o','a'] but ...
I'd like to plot a 2-d matrix from numpy as a colored matrix in Matplotlib. I have the following 9-by-9 array: my_array = diag(ones(9)) # plot the array pcolor(my_array) I'd like to set the first three elements of the diagonal to be a certain color, the next three to be a different color, and the last three a different color. I'd l...
I am using pcolor with a custom color map to plot a matrix of values. I set my color map so that low values are white and high values are red, as shown below. All of my matrices have values between 0 and 20 (inclusive) and I'd like 20 to always be pure red and 0 to always be pure white, even if the matrix has values that don't span the...
I am plotting a simple pair of subplots in matplotlib that are for some reason unevenly centered. I plot them as follows: plt.figure() # first subplot s1 = plt.subplot(2, 1, 1) plt.bar([1, 2, 3], [4, 5, 6]) # second subplot s2 = plt.subplot(2, 1, 2) plt.pcolor(rand(5,5)) # add colorbar plt.colorbar() # square axes axes_square(s1) axes...
I installed matplotlib using the Mac disk image installer for MacOS 10.5 and Python 2.5. I installed numpy then tried to import matplotlib but got this error: ImportError: numpy 1.1 or later is required; you have 2.0.0.dev8462. It seems to that version 2.0.0.dev8462 would be later than version 1.1 but I am guessing that matplotlib got co...
Hello, In brief, I am trying to call into a shared library from python, more specifically, from numpy. The shared library is implemented in C using sse2 instructions. Enabling optimisation, i.e. building the library with -O2 or –O1, I am facing strange segfaults when calling into the shared library via ctypes. Disabling optimisation (-O...
Hi, I have a number of C functions, and I would like to call them from python. cython seems to be the way to go, but I can't really find an example of how exactly this is done. My C function looks like this: void calculate_daily ( char *db_name, int grid_id, int year, double *dtmp, double *dtmn, double *dtmx, ...
How can I install numpy in virtualenv... easy_install numpy is throwing error.. I can not use the binary installer because this would install numpy in the python main installation and not in virtualenv.. Thanks ...
I am performing a least squares regression as below (univariate). I would like to express the significance of the result in terms of R^2. Numpy returns a value of unscaled residual, what would be a sensible way of normalizing this. field_clean,back_clean = rid_zeros(backscatter,field_data) num_vals = len(field_clean) x = field_clean[:,r...
I have a lookup table that is defined the following way: | <1 2 3 4 5+ -------|---------------------------- <10000 | 3.6 6.5 9.1 11.5 13.8 20000 | 3.9 7.3 10.0 13.1 15.9 20000+ | 4.5 9.2 12.2 14.8 18.2 TR_ua1 = np.array([ [3.6, 6.5, 9.1, 11.5, 13.8], [3.9, 7.3, 10.0, 13.1, 15.9], ...
Hi, The following example shows what I want to do: >>> test rec.array([(0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0)], dtype=[('ifAction', '|i1'), ('ifDocu', '|i1'), ('ifComedy', '|i1')]) >>> test[['ifAction', 'ifDocu']][0] (0, 0) >>> test[['ifAction', 'ifDocu']][0]...
Hi All: I have a strange problem in Python 2.6.5 with Numpy. I assign a numpy array, then equate a new variable to it. When I perform any operation to the new array, the original's values also change. Why is that? Please see the example below. Kindly enlighten me, as I'm fairly new to Python, and programming in general. -Sujan >>>...
Hello, I'm currently trying to learn Numpy and Python. Given the following array: import numpy as N a = N.array([[1,2],[1,2]]) Is there a function that returns the dimensions of a (e.g.a is a 2 by 2 array). size() returns 4 and that doesn't help very much. Thanks. ...
I'm performing a nested loop in python that is included below. This serves as a basic way of searching through existing financial time series and looking for periods in the time series that match certain characteristics. In this case there are two separate, equally sized, arrays representing the 'close' (i.e. the price of an asset) and...
Ironpython 2.6, python 2.6.5, numpy, SciPy import sys sys.path.append(r'D:\Python26\dll') sys.path.append(r'D:\Python26\Lib') sys.path.append(r'D:\Python26\Lib\site-packages') » import numpy Traceback (most recent call last): File "", line 1, in File "D:\Python26\Lib\site-packages\numpy\__init__.py", line 132, in File "D:\Pyth...
I use numpy for numerical linear algebra. I suspect that I can get much better performance if I make small modifications in how I carry out certain computations so that they are more memory efficient, for example. I was wondering if there is any form of instrumentation available in python to detect cache and TLB misses. There is a very ...
Hello! I have been working on a program where I need to slowly and smoothly change the pitch of a sine wave from one pitch to another. I am able to get an array of the frequency the pitch should be at any given moment (for instance, [440, 526.5, 634.2 794.8, 880], though much, much longer) but it seems I am unable to actually apply tha...
Hi. I need to write some code that deals with generating and manipulating multivariable polynomials. I'll outline my task with a simplified example. Lets say I am given three expressions: 2x^2, 3y + 1, and 1z. I then need to multiply these together which would give me 6x^2yz + 2x^2z. Then I would like to find the partial derivatives of...