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AddLogDerivative v1

../_images/AddLogDerivative-v1_dlg.png

AddLogDerivative dialog.

Summary

Add a sample log that is the first or second derivative of an existing sample log.

See Also

AddSampleLog

Properties

Name

Direction

Type

Default

Description

InputWorkspace

InOut

MatrixWorkspace

Mandatory

An input/output workspace. The new log will be added to it.

LogName

Input

string

Mandatory

The name that will identify the log entry to perform a derivative. This log must be a numerical series (double).

Derivative

Input

number

1

How many derivatives to perform. Default 1.

NewLogName

Input

string

Name of the newly created log. If not specified, the string ‘_derivativeN’ will be appended to the original name

Description

This algorithm performs a simple numerical derivative of the values in a sample log.

The 1st order derivative is simply: dy = (y1-y0) / (t1-t0), which is placed in the log at t=(t0+t1)/2

Higher order derivatives are obtained by performing the equation above N times. Since this is a simple numerical derivative, you can expect the result to quickly get noisy at higher derivatives.

If any of the times in the logs are repeated, then those repeated time values will be skipped, and the output derivative log will have fewer points than the input.

Usage

Example: Taking the derivative of logs

ws = CreateSampleWorkspace()
AddTimeSeriesLog(ws,"MyLog","2010-01-01T00:00:00",1.0,DeleteExisting=False)
AddTimeSeriesLog(ws,"MyLog","2010-01-01T00:00:10",2.0,DeleteExisting=False)
AddTimeSeriesLog(ws,"MyLog","2010-01-01T00:00:20",0.0,DeleteExisting=False)
AddTimeSeriesLog(ws,"MyLog","2010-01-01T00:00:30",5.0,DeleteExisting=False)

AddLogDerivative(ws,"MyLog",derivative=1,NewLogName="Derivative1")
AddLogDerivative(ws,"MyLog",derivative=2,NewLogName="Derivative2")
AddLogDerivative(ws,"MyLog",derivative=3,NewLogName="Derivative3")

for logName in ["MyLog","Derivative1","Derivative2","Derivative3"]:
    print("Log: {}".format(logName))
    print(ws.getRun().getProperty(logName).valueAsString())

Output:

Log: MyLog
2010-Jan-01 00:00:00  1
2010-Jan-01 00:00:10  2
2010-Jan-01 00:00:20  0
2010-Jan-01 00:00:30  5

Log: Derivative1
2010-Jan-01 00:00:05  0.1
2010-Jan-01 00:00:15  -0.2
2010-Jan-01 00:00:25  0.5

Log: Derivative2
2010-Jan-01 00:00:10  -0.03
2010-Jan-01 00:00:20  0.07

Log: Derivative3
2010-Jan-01 00:00:15  0.01

Categories: AlgorithmIndex | DataHandling\Logs

Source

C++ header: AddLogDerivative.h

C++ source: AddLogDerivative.cpp