# Quick start¶

This section provides a quick introduction to scipp. For in depth explanations refer to the sections in the user guide.

[1]:

import numpy as np
import scipp as sc


We start by creating some variables:

[2]:

var = sc.Variable(dims=['y', 'x'], values=np.random.rand(4,5))
sc.show(var)


Type the name of a variable at the end of a cell to generate an HTML respresentation:

[3]:

var

[3]:

scipp.Variable (160 Bytes)
• (y: 4, x: 5)
float64
0.36, 0.19, ..., 0.1, 0.56
Values:array([[0.35620622, 0.19304515, 0.66822755, 0.9621907 , 0.03204145],
[0.94979449, 0.13841741, 0.27123956, 0.57415605, 0.84638204],
[0.89359542, 0.79761112, 0.63548611, 0.61090044, 0.30631625],
[0.92824375, 0.75823889, 0.74209011, 0.10439147, 0.56136769]])
[4]:

x = sc.Variable(dims=['x'], values=np.arange(5), unit=sc.units.m)
y = sc.Variable(dims=['y'], values=np.arange(4), unit=sc.units.m)


We combine the variables into a data array:

[5]:

array = sc.DataArray(
data=var,
coords={'x': x, 'y': y})
sc.show(array)
array

[5]:

scipp.DataArray (232 Bytes)
• y: 4
• x: 5
• x
(x)
int64
m
0, 1, 2, 3, 4
Values:array([0, 1, 2, 3, 4])
• y
(y)
int64
m
0, 1, 2, 3
Values:array([0, 1, 2, 3])
• (y, x)
float64
0.36, 0.19, ..., 0.1, 0.56
Values:array([[0.35620622, 0.19304515, 0.66822755, 0.9621907 , 0.03204145],
[0.94979449, 0.13841741, 0.27123956, 0.57415605, 0.84638204],
[0.89359542, 0.79761112, 0.63548611, 0.61090044, 0.30631625],
[0.92824375, 0.75823889, 0.74209011, 0.10439147, 0.56136769]])

Variables can have uncertainties. Scipp stores these as variances (the square of the standard deviation):

[6]:

array.variances = np.square(np.random.rand(4,5))
sc.show(array)


We create a dataset:

[7]:

dataset = sc.Dataset(
data={'a': var},
coords={'x': x, 'y': y, 'aux': x})
dataset['b'] = array
dataset['scalar'] = 1.23 * (sc.units.m / sc.units.s)
sc.show(dataset)


We can slice variables, data arrays, and datasets using a dimension label and an index or a slice object like i:j:

[8]:

dataset['c'] = dataset['b']['x', 2]
sc.show(dataset)
dataset

[8]:

scipp.Dataset (840 Bytes out of 1.13 KB)
• y: 4
• x: 5
• aux
(x)
int64
m
0, 1, 2, 3, 4
Values:array([0, 1, 2, 3, 4])
• x
(x)
int64
m
0, 1, 2, 3, 4
Values:array([0, 1, 2, 3, 4])
• y
(y)
int64
m
0, 1, 2, 3
Values:array([0, 1, 2, 3])
• a
(y, x)
float64
0.36, 0.19, ..., 0.1, 0.56
σ = 0.56, 0.42, ..., 0.73, 0.1
Values:array([[0.35620622, 0.19304515, 0.66822755, 0.9621907 , 0.03204145],
[0.94979449, 0.13841741, 0.27123956, 0.57415605, 0.84638204],
[0.89359542, 0.79761112, 0.63548611, 0.61090044, 0.30631625],
[0.92824375, 0.75823889, 0.74209011, 0.10439147, 0.56136769]])Variances (σ²):array([[0.31252281, 0.1786297 , 0.10900878, 0.76808841, 0.63674344],
[0.01641601, 0.6308399 , 0.10583196, 0.51720851, 0.33267364],
[0.39508017, 0.62752704, 0.9755135 , 0.10787153, 0.40062838],
[0.01848075, 0.03640689, 0.80584553, 0.52729343, 0.01014745]])
• b
(y, x)
float64
0.36, 0.19, ..., 0.1, 0.56
σ = 0.56, 0.42, ..., 0.73, 0.1
Values:array([[0.35620622, 0.19304515, 0.66822755, 0.9621907 , 0.03204145],
[0.94979449, 0.13841741, 0.27123956, 0.57415605, 0.84638204],
[0.89359542, 0.79761112, 0.63548611, 0.61090044, 0.30631625],
[0.92824375, 0.75823889, 0.74209011, 0.10439147, 0.56136769]])Variances (σ²):array([[0.31252281, 0.1786297 , 0.10900878, 0.76808841, 0.63674344],
[0.01641601, 0.6308399 , 0.10583196, 0.51720851, 0.33267364],
[0.39508017, 0.62752704, 0.9755135 , 0.10787153, 0.40062838],
[0.01848075, 0.03640689, 0.80584553, 0.52729343, 0.01014745]])
• c
(y)
float64
0.67, 0.27, 0.64, 0.74
σ = 0.33, 0.33, 0.99, 0.9
• aux
()
int64
m
2
Values:array(2)
• x
()
int64
m
2
Values:array(2)
Values:array([0.66822755, 0.27123956, 0.63548611, 0.74209011])Variances (σ²):array([0.10900878, 0.10583196, 0.9755135 , 0.80584553])
• scalar
()
float64
m/s
1.23
Values:array(1.23)

We can also generate table representations (only 0-D and 1-D) and plots:

[9]:

sc.table(dataset['y', 2])

[10]:

sc.plot(dataset)


Arithmetic operations can be combined with slicing and handle propagation of uncertainties and units:

[11]:

print(dataset)

<scipp.Dataset>
Dimensions: Sizes[y:4, x:5, ]
Coordinates:
aux                         int64              [m]  (x)  [0, 1, ..., 3, 4]
x                           int64              [m]  (x)  [0, 1, ..., 3, 4]
y                           int64              [m]  (y)  [0, 1, 2, 3]
Data:
a                         float64  [dimensionless]  (y, x)  [0.356206, 0.193045, ..., 0.104391, 0.561368]  [0.312523, 0.178630, ..., 0.527293, 0.010147]
b                         float64  [dimensionless]  (y, x)  [0.356206, 0.193045, ..., 0.104391, 0.561368]  [0.312523, 0.178630, ..., 0.527293, 0.010147]
c                         float64  [dimensionless]  (y)  [0.668228, 0.271240, 0.635486, 0.742090]  [0.109009, 0.105832, 0.975513, 0.805846]
Attributes:
aux                         int64              [m]  ()  [2]
x                           int64              [m]  ()  [2]
scalar                    float64            [m/s]  ()  [1.230000]


[12]:

dataset['b']['y', 0:2] -= dataset['y', 0:2]['a']['x', 0]
dataset['b'] *= dataset['scalar']
print(dataset)

<scipp.Dataset>
Dimensions: Sizes[y:4, x:5, ]
Coordinates:
aux                         int64              [m]  (x)  [0, 1, ..., 3, 4]
x                           int64              [m]  (x)  [0, 1, ..., 3, 4]
y                           int64              [m]  (y)  [0, 1, 2, 3]
Data:
a                         float64            [m/s]  (y, x)  [0.000000, -0.200688, ..., 0.128402, 0.690482]  [0.945632, 0.743065, ..., 0.797742, 0.015352]
b                         float64            [m/s]  (y, x)  [0.000000, -0.200688, ..., 0.128402, 0.690482]  [0.945632, 0.743065, ..., 0.797742, 0.015352]
c                         float64            [m/s]  (y)  [0.383786, -0.834623, 0.781648, 0.912771]  [0.637735, 0.184949, 1.475854, 1.219164]
Attributes:
aux                         int64              [m]  ()  [2]
x                           int64              [m]  ()  [2]
scalar                    float64            [m/s]  ()  [1.230000]



Finally, type the imported name of the scipp module at the end of a cell for a list of all current scipp objects (variables, data arrays, datasets). Click on entries to expand nested sections:

[13]:

sc

Variables:(3)
var
scipp.Variable (320 Bytes)
• (y: 4, x: 5)
float64
m/s
0.0, -0.2, ..., 0.13, 0.69
σ = 0.97, 0.86, ..., 0.89, 0.12
Values:array([[ 0.        , -0.20068812,  0.38378623,  0.7453609 , -0.39872267],
[ 0.        , -0.9979938 , -0.83462256, -0.46203528, -0.12719731],
[ 1.09912236,  0.98106168,  0.78164792,  0.75140754,  0.37676899],
[ 1.14173982,  0.93263384,  0.91277084,  0.12840151,  0.69048226]])Variances (σ²):array([[0.94563151, 0.74306463, 0.63773513, 1.63485672, 1.43614491],
[0.04967157, 0.97923347, 0.18494896, 0.80732054, 0.52813774],
[0.59771679, 0.94938567, 1.47585437, 0.16319883, 0.60611068],
[0.02795953, 0.05507998, 1.21916371, 0.79774224, 0.01535208]])
x
scipp.Variable (40 Bytes)
• (x: 5)
int64
m
0, 1, 2, 3, 4
Values:array([0, 1, 2, 3, 4])
y
scipp.Variable (32 Bytes)
• (y: 4)
int64
m
0, 1, 2, 3
Values:array([0, 1, 2, 3])
DataArrays:(1)
array
scipp.DataArray (392 Bytes)
• y: 4
• x: 5
• x
(x)
int64
m
0, 1, 2, 3, 4
Values:array([0, 1, 2, 3, 4])
• y
(y)
int64
m
0, 1, 2, 3
Values:array([0, 1, 2, 3])
• (y, x)
float64
m/s
0.0, -0.2, ..., 0.13, 0.69
σ = 0.97, 0.86, ..., 0.89, 0.12
Values:array([[ 0.        , -0.20068812,  0.38378623,  0.7453609 , -0.39872267],
[ 0.        , -0.9979938 , -0.83462256, -0.46203528, -0.12719731],
[ 1.09912236,  0.98106168,  0.78164792,  0.75140754,  0.37676899],
[ 1.14173982,  0.93263384,  0.91277084,  0.12840151,  0.69048226]])Variances (σ²):array([[0.94563151, 0.74306463, 0.63773513, 1.63485672, 1.43614491],
[0.04967157, 0.97923347, 0.18494896, 0.80732054, 0.52813774],
[0.59771679, 0.94938567, 1.47585437, 0.16319883, 0.60611068],
[0.02795953, 0.05507998, 1.21916371, 0.79774224, 0.01535208]])
Datasets:(1)
dataset
scipp.Dataset (840 Bytes out of 1.13 KB)
• y: 4
• x: 5
• aux
(x)
int64
m
0, 1, 2, 3, 4
Values:array([0, 1, 2, 3, 4])
• x
(x)
int64
m
0, 1, 2, 3, 4
Values:array([0, 1, 2, 3, 4])
• y
(y)
int64
m
0, 1, 2, 3
Values:array([0, 1, 2, 3])
• a
(y, x)
float64
m/s
0.0, -0.2, ..., 0.13, 0.69
σ = 0.97, 0.86, ..., 0.89, 0.12
Values:array([[ 0.        , -0.20068812,  0.38378623,  0.7453609 , -0.39872267],
[ 0.        , -0.9979938 , -0.83462256, -0.46203528, -0.12719731],
[ 1.09912236,  0.98106168,  0.78164792,  0.75140754,  0.37676899],
[ 1.14173982,  0.93263384,  0.91277084,  0.12840151,  0.69048226]])Variances (σ²):array([[0.94563151, 0.74306463, 0.63773513, 1.63485672, 1.43614491],
[0.04967157, 0.97923347, 0.18494896, 0.80732054, 0.52813774],
[0.59771679, 0.94938567, 1.47585437, 0.16319883, 0.60611068],
[0.02795953, 0.05507998, 1.21916371, 0.79774224, 0.01535208]])
• b
(y, x)
float64
m/s
0.0, -0.2, ..., 0.13, 0.69
σ = 0.97, 0.86, ..., 0.89, 0.12
Values:array([[ 0.        , -0.20068812,  0.38378623,  0.7453609 , -0.39872267],
[ 0.        , -0.9979938 , -0.83462256, -0.46203528, -0.12719731],
[ 1.09912236,  0.98106168,  0.78164792,  0.75140754,  0.37676899],
[ 1.14173982,  0.93263384,  0.91277084,  0.12840151,  0.69048226]])Variances (σ²):array([[0.94563151, 0.74306463, 0.63773513, 1.63485672, 1.43614491],
[0.04967157, 0.97923347, 0.18494896, 0.80732054, 0.52813774],
[0.59771679, 0.94938567, 1.47585437, 0.16319883, 0.60611068],
[0.02795953, 0.05507998, 1.21916371, 0.79774224, 0.01535208]])
• c
(y)
float64
m/s
0.38, -0.83, 0.78, 0.91
σ = 0.8, 0.43, 1.21, 1.1
• aux
()
int64
m
2
Values:array(2)
• x
()
int64
m
2
Values:array(2)
Values:array([ 0.38378623, -0.83462256,  0.78164792,  0.91277084])Variances (σ²):array([0.63773513, 0.18494896, 1.47585437, 1.21916371])
• scalar
()
float64
m/s
1.23
Values:array(1.23)
[13]:

<module 'scipp' from '/usr/share/miniconda/envs/tempenv/lib/python3.7/scipp/__init__.py'>