CODEWITHSUNDEEP
pythonnumpysquare-rootelementwise-operations
Lokesh
Lokesh

Reputation: 35

keep getting 'only length-1 arrays can be converted to python scalars'

I keep getting the error only length-1 arrays can be converted to Python scalars. I am getting error due to the variable 'uc' as it is an array of 214 elements.

The error states:

  File "/home/lokesh/PycharmProjects/Cross_Range_Imaging/Cross_Range.py", line 68, in <module>
    dis = cmath.sqrt(Xc ** 2 + (Yc + yn[i] - uc) ** 2)
TypeError: only length-1 arrays can be converted to Python scalars

Tried code:


import math
import cmath
import numpy as np

cj = cmath.sqrt(-1)
pi2 = 2 * cmath.pi
c = 3e8
fc = 200e6
Xc = 1e3
Yc = 0
Y0 = 100
L = 400
theta_c = cmath.atan(Yc / Xc)
L_min = max(Y0, L)
lamda = c / fc
Xcc = Xc / np.power(np.cos(theta_c),2)
duc = (Xcc * lamda) / (4 * Y0)
mc = 2 * math.ceil(L_min / duc)
uc = duc * np.arange(-mc / 2, mc/2)
k = pi2 / lamda

yn = [0, 70, 66.2500, -80]
fn = [1, 1, 1, 1]
ntarget = 4
s = np.zeros((1, mc))

for i in np.arange(ntarget):
    dis = cmath.sqrt(Xc ** 2 + (Yc + yn[i] - uc) ** 2)
    s = s + np.multiply(fn[i] * np.exp(-cj * 2 * k * dis), (abs(uc) <= L))

The expected result values of variable 'dis' are 1x214 double and variable 's' are 1x214 complex double

Upvotes: 1

Views: 372

Answers (1)

Allison Bellows
Allison Bellows

Reputation: 151

Try dis = np.sqrt(Xc ** 2 + (Yc + yn[i] - uc) ** 2).

cmath.sqrt operates on scalars, not arrays. You have to use an array operation like numpy.sqrt() to get the square root of each value in the array.

Note: this will create dis with shape (214,), which will still work for setting s, but if you want dis to be (1,214) you may want to add .reshape(1, 214) to the end of my suggested code.

Upvotes: 2

Related Questions