使用Numpy将MATLAB切片转换为Python

Question

I am having trouble converting some MATLAB code into python. I am trying to build a signal by adding in shifted copies of base signal into a much longer one. The code that works in MATLAB is

function [time, signal] = generateRandomSignal(pulse,data,samples,Tb)
N = length(data);
time = linspace(0,N*Tb,samples*N);
signal = zeros(1,length(time));
k = 1;
for n = 1:N
        window = k:k+samples-1;
        signal(window) = signal(window) + data(n)*pulse;
        k = k + samples;
end

In python using the variable to slice the larger array wasn't working so I changed that but now I got what I think should work but I keep getting errors about inconsistent array sizes even though when I inspect the sizes in a debugger it looks like it should work.

from numpy import *
def generateRandomSignal(pulse,data,samples,Tb):
    N = data.size;
    time = linspace(0,N*Tb,samples*N);
    signal = zeros((1,time.size));
    k = 0;
    for n in range(0,N):
            signal[k:k+samples] = signal[k:k+samples].copy() + data[n]*pulse[:].copy();
            k = k + samples;
    return time, signal

What is the correct way to do this in Python?

EDIT: Minimal expected input and output

Input
  data = [1, -1, 0, 1, 1]
  pulse = [1, 1, 1]
  samples = 3. #length of pulse
  Tb = 0.1

Output
  signal = [1, 1, 1, -1, -1, -1, 0, 0, 0, 1, 1, 1, 1, 1, 1]
  time = vector of 15 points evenly spaced from 0 to 0.3.  (Not the problem)

EDIT2 Error

ValueError: operands could not be broadcast together with shapes (1920,) (1,4410)

That is the actual error produced. (1,4410) is the correct shape for the pulse array but I have no idea where the 1920 is coming from or what the empty comma means

Answer 1

Change your definition of signal to signal = zeros(time.size) . Unlike Matlab, NumPy's 1D arrays have shape (N,) , not (N,1) .

Answer 2

I can't see why you should have 0 index in signal:

signal[0,k:k+samples] = signal[0,k:k+samples].copy() + data[n]*pulse[:].copy();