schrodinger.application.desmond.measurement module¶
A class for simple arithmetic with uncertainty.
Copyright Schrodinger, LLC. All rights reserved.
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class
schrodinger.application.desmond.measurement.
Measurement
(value, uncertainty=nan)¶ Bases:
object
Basic method for uncertainty propagation: Say we have a few measurements: x1, x2, x3, …, and they each has a uncertainty: d1, d2, d3, …, respectively. Now we have a function: f( x1, x2, x3, … ), we want to get the value of this function with given measurements x1, x2, x3, … and also the uncertainty of the result of f. A way to do this is the following:
We need to get the contribution to the uncertainty of f result due to each measurement: fd1, fd2, fd3, … This can be given by the following equations:
fd1 = df / dx1 * d1 fd2 = df / dx2 * d2 fd3 = df / dx3 * d3 …
where `df / dx1’ is a partial derivative of f with respect to x1.
- With fd1, fd2, fd3, …, we can get the uncertainty of f using this equation:
fd = math.sqrt( fd1 * fd1 + fd2 * fd2 + fd3 * fd3 + … )
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__init__
(value, uncertainty=nan)¶
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to_string
(num_digits)¶ Convert
Measurement
to string with givennum_digits
decimal places
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classmethod
from_string
(s)¶ Convert string (e.g: “5.0+-0.3”) to
Measurement
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schrodinger.application.desmond.measurement.
string2measurement
(s)¶ Convert string (e.g: “5.0+-0.3”) to
Measurement
This method is deprecated in favor of Measurement.from_string