Error:numpy.narray object not callable

Question

I am trying to convert Matlab code to Python but it gives an error when I convert the following line:

Matlab Code

md(1,index) = (-1)^bits(m);

Python equivalent

md[index]=(-1)**bits(m)

Error

md[index]=(-1)**bits(m)
TypeError: 'numpy.ndarray' object is not callable

Matlab Code

fdel=2;
fn=10;

zeta=1/sqrt(2);
spb=100;
npts=2000;
fs=2000;
freq_in = zeros(1,2000);      % initialize input frequency array
phi_in = zeros(1,2000);       % initialize input phase array
t = (0:(npts-1))/fs;            % generate vector of sample times
nsettle = fix(npts/10);         % set settle time as 0.1*npts
tsettle = nsettle/fs;           % set settle time
% 
% %       The following three lines of code generate the arrays of the
% %       input frequency and input phase. 
% 
phin1 = 2*pi*fdel*(t-tsettle);
freq_in = [zeros(1,nsettle),fdel*ones(1,npts-nsettle)];
phi_in = [zeros(1,nsettle),phin1(1,(nsettle+1):npts)];
% 
% %       Generate the QPSK input signal and input signal.
% 
nbits = npts/spb;               % Determine number of bits
md = zeros(1,nbits*spb);
bits = round(rand(1,nbits));
for m=1:nbits

 for n=1:spb
  index = (m-1)*spb + n;
  % error making line
    md(1,index) = (-1)^bits(m);
 end
 end

Python Code

fdel=2
fn=10
zeta=1/sqrt(2)
spb=100
npts=2000
fs=2000
freq_in=zeros(2000)
phi_in=zeros(2000)
t=(arange(0,npts-1))/fs
nsettle=fix(npts/10)
tsettle=nsettle/fs
phin1=2*pi*fdel*(t-tsettle)
freq_in=array([zeros(nsettle),fdel*ones(npts-nsettle)])
phi_in=array([zeros(nsettle),phin1[nsettle+1:npts]])
nbits=npts/spb

md=zeros(nbits*spb)
bits=around(np.random.uniform((nbits,)))

for m in arange(0,nbits):
    for n in arange(0,spb):
       index=(m-1)*spb+n
       md[index]=(-1)**bits(m)

I suspect what that error means is that `bits(m)` is not a function, i.e. you shouldn't use parens to give it the index. Try `bits[m]` instead. — darthbith, Aug 12 '13 at 12:34
-1: [python debugging tips](http://stackoverflow.com/questions/1623039/python-debugging-tips) — Schorsch, Aug 12 '13 at 12:46
thanks it actually helped...but now its giving index out of bound — marriam nayyer, Aug 12 '13 at 13:08

score 4 · Accepted Answer · answered Aug 12 '13 at 12:53

4

This error is becase you are indexing an array with () instead of [], example:

np.arange(10)(1)

gives:

TypeError: 'numpy.ndarray' object is not callable

While:

np.arange(10)[1]

gives:

answered Aug 12 '13 at 12:53

Saullo G. P. Castro

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score 3 · Answer 2 · answered Aug 12 '13 at 13:07

As Saullo pointed out in his answer you are not indexing in the right way, however you are not porting the code correctly. freq_in and phi_in are not properly defined and you are not generating a random vector in bits, take a look to the following code:

import numpy as np

fdel = 2
fn = 10
zeta = 1 / np.sqrt(2)
spb = 100
npts = 2000
fs = 2000
freq_in = np.zeros((2000))
phi_in = np.zeros((2000))
t = np.arange(0,npts) / fs
nsettle = np.fix(npts/10)
tsettle = nsettle
phin1 = 2 * np.pi * fdel * (t-tsettle)
freq_in = np.hstack((np.zeros(nsettle), fdel * np.ones(npts-nsettle)))
phi_in = np.hstack((np.zeros(nsettle), phin1[int(nsettle):int(npts)]))

nbits = npts / spb

md = np.zeros(nbits * spb);
bits = np.random.randint(2, size=nbits)
for m in np.arange(0,nbits):
    for n in np.arange(0,spb):
       index = (m-1) * spb + n
       md[index]=(-1)**bits[m]

Error:numpy.narray object not callable

2 Answers2