# All Questions

Tagged with floating-point numpy

63
questions with no upvoted or accepted answers

7votes

1answer

774views

### How to avoid Numpy type conversions?

Is it possible to avoid or emit warnings for automatic Numpy type conversions from integer and 32 bit float arrays to 64 bit float arrays?
My use case for this is that I'm developing a large analysis ...

4votes

0answers

112views

### Is there a way to force numpy.set_printoptions to show the exact float value?

Following question 59674518, is there a way for numpy.set_printoptions to ensure the EXACT float value is displayed, without displaying trailing zeros, and without knowing the value a priori? I have ...

4votes

1answer

502views

### Why does complex floating-point division underflow weirdly with NumPy?

Consider this code:
import numpy
numpy.seterr(under='warn')
x1 = 1 + 1j / (1 << 533)
x2 = 1 - 1j / (1 << 533)
y1 = x1 * 1.1
y2 = x2 * 1.1
z1 = x1 / 1.1
z2 = x2 / 1.1
print(numpy.divide(1, ...

3votes

0answers

81views

### wrong result on adition of numbers larger than epsilon using numpy.float128

Considering that epsilon is the smallest number that you can add to one.
I'm getting 1 instead of 1+epsilon when I perform the addition and print the result.
I've implemented a getEpsilon function. I ...

3votes

0answers

107views

### Is there a way to disable denormals in numpy? (Enabling ftz and daz flags)

I'm trying to perform a few calculations on floating point numbers that are close to the float32 min. I want the numbers to be flushed to zero when they drop below the float32 minimum instead of ...

2votes

0answers

59views

### Python numpy:How many digits does np.float64 have?

So I'm doing taylor expansion for exp(11.2). When I print all terms, I find some terms have 15 digits but some have 17 digits. I wonder why is that happening?

2votes

1answer

243views

### Numpy matrix multiplication instability across rows

I am multiplying two float64 matrices with the following values:
import numpy as np
# 4x5 matrix with identical columns.
x = np.zeros((4, 5,), dtype=np.float64)
x[1] = 1
x[3] = -3
w = np.array([1, 1,...

2votes

2answers

86views

### python search float return wrong because of precision problem?

I want to find a float in a arry like this:
arr = np.asarray([1351.1 , 1351.11, 1351.14, 1351.16, 1351.17])
index = np.searchsorted(arr, 1351.14, side="right") - 1 # return 2
But I find ...

2votes

0answers

44views

### Slicing a pandas dataframe based on less or equal citerion

I bet this question has been answered a number of times but I am struggling to find a definitive solution.
I need to delete dataframe rows based on a greater or equal condition. Because of float64 ...

2votes

0answers

100views

### Is there a way for Python to read __float128 from a binary file?

I am trying to read a binary file that stores some __float128 variables from other C project using Python.
I've been looking in the numpy.float128 but it seems that it is implemented in a different ...

2votes

1answer

73views

### JSON cannot handel numpy's float128 type

I need to dump numpy arrays of dtype float128 to JSON. For that purpose I wrote a custom array encoder, that properly handles arrays by calling tolist() on them. This works perfectly fine for all real ...

2votes

1answer

197views

### Why is my calculation of covariance not precise

I am trying to write a function for calculating covariance matrix. I am getting very similar answer to the built in np.cov() but not exactly. There seems to be a loss of accuracy and precision. Does ...

2votes

0answers

7kviews

### DeprecationWarning: object of type <class 'float'> cannot be safely interpreted as an integer

My code snippet is as follows:
data,l = make_moons(100000)
s = np.random.permutation(100000);
temp1 = data[s[0:200],:] # Random Sampling of 200 columns
temp2 = cdist(data,temp1) # Pairwise distance ...

2votes

0answers

565views

### How to print scientific notation with all significant digits moved after decimal point in python

I am trying to print scientific numbers with all the significant digits after the decimal point. `
Python's scientific notation prints with one digit before the dot like 1.2345678E+03,
'%E' % ...

2votes

3answers

1kviews

### Inconsistent type conversion in python/numpy when using scalars or lists/arrays

I have a question about the strange way python/numpy performs type conversion. When I perform an arithmetic operation between a float32 and a float64 number, the lower precision is converted to ...

2votes

1answer

668views

### numpy/pandas: test float64 arrays are equal up to significant digits

I have two pandas data frames in which I store money amounts, i.e. decimal numbers with at most 15 significant decimal digits. Since float64 has a precision of 15 significant decimal digits, this ...

2votes

0answers

3kviews

### Python float types vs Decimal

I am an intern at TCD, Physics.
I wrote a code to perform some data analysis on random particle packings. The code is written in Python.
The code reads in columns of data from a .txt file, provided ...

1vote

0answers

229views

### How can I convert XYZ point cloud to binary mask image

I want to convert a set of point cloud (X, Y, Z) to a binary mask image using python. The problem is that these points are float and out of range of 0-255. To more specific, the points are related to ...

1vote

0answers

39views

### Benchmarking Float Precision per Operation in Numpy

I want to benchmark the error between 64-bit floats and 32 bit floats in Numpy for addition and multiplication. Unfortunately, I could not find exactly what I was looking for when searching for the ...

1vote

0answers

101views

### Covariance matrices should be equal but are not

I'm computing covariance in two ways that I think should tie out, but they do not.
Method 1: Compute the covariance matrix of a slice of an array of data
Method 2: Compute the covariance matrix of the ...

1vote

1answer

33views

### Is it possible to get reserved special numbers of double-precision binary floating-point with NumPy or some other package in Python

per wiki, Double-precision binary floating-point has Exponents
range from −1022 to +1023 because exponents of −1023 (all
0s) and +1024 (all 1s) are reserved for special numbers.
is it possible ...

1vote

0answers

105views

### numpy: wrong result when casting large float32 to int32

I have a numpy array of type np.float32 (actually no fraction part), and I expect it to be casted to only the integer part (2143289300), but the result below is different(2143289344), do you know why? ...

1vote

0answers

437views

### Can I use Python's Decimal type with NumPy?

I'm doing some calculations with Python3 and NumPy using float64 and sometimes, when I change my formulas a little (but mathematically equivalent), then I get slightly different results. I know that ...

1vote

0answers

519views

### Floats subtraction / addition - calculate loss of precision

I am trying to wrap my mind around floating-point arithmetics and related loss of precision. I do understand that I can lose a lot of precision when I perform addition of big and small numbers (due to ...

1vote

0answers

272views

### Python+numpy: a lucky floating point case?

I'm inverting a very simple matrix, and I stumbled in something which I don't understand.
EDIT: In the original post I forgot to take care of the fact that numpy defaults to float64, hence the ...

1vote

0answers

4kviews

### RuntimeWarning: invalid value encountered in double_scalars

Steps of the algorithms:
1- Initialize with P and Q
2- the main process of Algorithm is started as the first for (loop) becomes to begin.
This is the program that I wrote for above steps:
#!/usr/...

1vote

3answers

1kviews

### Generate array of floats within possible MAX and MIN

I'm trying to generate floats however not within [0-1) but sys.float_info.max and sys.float_info.min. Unfortunately Python's random and Numpy random work as this way
a + (b-a) * random()
But random()...

0votes

0answers

37views

### Fast inverse square root in python on float32

I have done some checks for the fast inverse square root method in python (jupyterlab using python version 3.8.8) and for some reason then I've come to the conclusion that I must either be doing ...

0votes

0answers

70views

### how to convert pandas dataframe into a numpy array with floats

I cannot convert it using the following commands
import pandas as pd
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt
df = pd.read_csv('sample.csv')
print(df.head())
...

0votes

1answer

32views

### Why does cholesky factorization fail for pascal matrices of big size?

I want to perform cholesky factorization for pascal matrix of size 50. The values become too large so scipy.linalg.pascal returns matrix of object type.
A_scipy = scipy.linalg.pascal(50)
A_scipy.dtype
...

0votes

0answers

24views

### set_print_options failes when transfering scientific notation to float with specified precision in numpy

Ok I have tried hundred things, I went through old questions and I read the numpy.set_print_options but it won't work.
So I have an array which looks something like this when printed:
array([[2....

0votes

0answers

22views

### numpy seterrcall, how to flag the object that caused the flouting point error?

I have a function that loops through a list of objects, each these objects are associated with numpy functions (add, multiple, divide).
When calling the object with arguments, the associated numpy ...

0votes

1answer

168views

### How can .0 decimals be included when working with numpy floats

I have a numpy array containing mostly whole numbers and floats. The way I understand it, arrays are always stored as floats, and so the integers are stored as <number>.0. I want to work with ...

0votes

0answers

19views

### How to find the bit value (precision) of a trained CNN/ANN model?

I have CNN model (ONNX) taken from Github repository for general purpose classification. I want to find if the model weights are trained with single precision values (32 bit) or half precision values (...

0votes

0answers

46views

### Python, compare if a Float is close to an Integer

I'm coding a program to analyse sentiments in Tweets. I want to perform a test where I have a dataset of Tweets like this :
label,text
0, blabla
1, blablabla
0, blablablabla
where label is ...

0votes

0answers

103views

### numpy.float64' object cannot be interpreted as an integer

I have some problems running this code on the hillslope diffuson equation. I am not an expertise in python code! Even if I correcte some other problems the code return me again the problem about '...

0votes

0answers

74views

### How to efficiently encode a 1D float32 numpy array in json without loss of precision?

I have a 1D numpy array of type float32. I want to create a JSON file which efficiently encodes the numpy array without degrading the precision. Since JSON is encoded in characters and not numbers, ...

0votes

1answer

285views

### python numpy.single gives different result when using out parameter

I am trying to cast from a double precision array to single precision. To optimize on space I tried using the out argument so that numpy doesn't allocate additional space. However the results seem ...

0votes

0answers

66views

### Float64 granularity: what is the longest possible line?

The IEEE defines float64's range from -2.23e-308 to +1.8e+308. But what is the granularity implied by this range? That is, what is the maximum number of nonzero increments we can make from the minimum ...

0votes

0answers

106views

### Precision loss in numpy float32 conversion

I'm experiencing a weird behaviour when converting a scalar or array to numpy.float32. I suspect it's linked to the precision limit but can't exactly pinpoint where it's coming from. Here is an ...

0votes

1answer

132views

### How to read multiple data types from memoryview in Python?

I am reading sensor data, which has 6 columns, first four are 32 bit floats, and the last two are unsigned integers. Here is how it is converted into a numpy array:
data = np.frombuffer(sensor_data....

0votes

1answer

413views

### Constrain numpy to automatically convert integers to floating-point numbers (python 3.7)

I have just made the following mistake:
a = np.array([0,3,2, 1])
a[0] = .001
I was expecting 0 to be replaced by .001 (and the dtype of my numpy array to automatically switch from int to float). ...

0votes

1answer

249views

### Python iterate over a float array or list

I have a Pandas dataframe and i Need to create a function to a specific column in it which has only Floating Point values. i can retrieve the column and convert it to list or Array. But Once i use for ...

0votes

3answers

717views

### Conversion from float (native float or numpy.float64) to integer not working

I have a dataframe thats loaded with floats and NaNs. I need to convert all the decimals/floats to integers. I checked that all types are numpy.float64 but my conversion to integer does not work. This ...

0votes

0answers

445views

### Check if byte string represents float or int

I have some byte strings and I don't know if they are integers or floats.
Lets create some example data:
import numpy as np
arr_int = np.array([17, int(1e10), 34567])
arr_float = np.array([17.17,...

0votes

2answers

599views

### Checking if float value is in numpy array

I am trying to find out if a value is in numpy array. The array is generated using linspace method and gets float64 type. My value is float type. As the outcome "value in array" check always returns ...

0votes

1answer

202views

### python (numpy, float, or decimal) - set min amd max decimal places in string representation

In Python (either in regular float, numpy, or decimal), is there a way to set both a min and max decimal places when getting the string representation?
Say I want min decimal places to be 2, and max ...

0votes

1answer

181views

### How can I compare two arrays with different sizes but with some floats that are approximate? [Python3]

How can I compare two arrays with different sizes but with some floats that are approximate? For example:
# I have two arrays
a = np.array( [-2.83, -2.54, ..., 0.05, ..., 2.54, 2.83] )
b = np.array( [...

0votes

0answers

86views

### "'type' object is not a subscriptable error" in Python

import pyglet
class CarMap:
def __init__(self):
self.in_map = [341, 161, 452, 121, 567, 123, 650, 160, 678, 241, 613, 340, 654, 467, 611, 508, 506, 514, 416, 437,
289, 401, 207,...

0votes

0answers

123views

### How to make sure a probability distribution add up to exactly 1.0 in python numpy?

I am using Latent Dirichlet Allocation function in sklearn: http://scikit-learn.org/stable/modules/generated/sklearn.decomposition.LatentDirichletAllocation.html
The output is a 2d numpy array of ...