IndexError: tuple index out of range, error when trying to integrate the fucntion

Question

I am trying to calculate a value of function f_integ, which is a result of integration of function f from 0 to x_v.

   f = lambda x : x + 1

    def f_integ(x_array):
        int_result = np.zeros_like(x_array)
        indexes = np.shape(x_array)[0]
        for ind in range(indexes):
            x_v = x_array[ind]
            int_result[ind] = integ.quad(f, 0.0, x_v)[0]
        return int_result

    C = f_integ(1)
    print "C", C

When I run this, I get the following error:

Traceback (most recent call last):
  File "untitled.py", line 117, in <module>
    C = f_integ(1)
  File "scr1.py", line 110, in f_integ
    indexes = np.shape(x_array)[0]
IndexError: tuple index out of range

I know that quad() returns a tuple, but I can not figure out how to put a number as an argument in the result of integration. I'm new to Python, please help.

Post the full error message, including the stack trace, and a [mcve] as well. — juanpa.arrivillaga, Sep 28 '17 at 19:01

Antimony · Accepted Answer · 2017-09-28T19:16:18.073

1

Call the function like this:

C = f_integ(np.array([1]))
print "C", C

Currently you are passing a number to f_integ(), not an array. When it encounters np.shape(x_array)[0], the shape of a number is just (), so it cannot return anything at index 0 for an empty tuple.

edited Sep 28 '17 at 19:16

answered Sep 28 '17 at 19:10

Antimony

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Good catch. But it has a shape just fine, but that shape is an empty tuple, which will throw an IndexError with anything you try to index into it. – juanpa.arrivillaga Sep 28 '17 at 19:13
You're welcome! Could you accept the answer since it worked for you? – Antimony Sep 28 '17 at 23:14

IndexError: tuple index out of range, error when trying to integrate the fucntion

1 Answers1